Tait TB7100 Service Manual Download Page 45

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TB7100 Service Manual

Circuit Descriptions

October 2005

Figure 4.3

Block diagram of the receiver circuitry

Image Filter

LNA

Image Filter

First IF

BPF 1

Amplifier

First IF

BPF 2

Quadr

ature

Demodulator

Bias

Network

wer

Supply

CODEC

and

Audio

Digital

Boar

PLL

Noise

Blank

(VHF only)

Switch

(VHF only)

ansmitter

equency

Synthesizer

Mixer

Receiver

VCO

CDC RX PIN

CDC RX

RX CDC QN

RX CDC QP

RX CDC IN

RX CDC IP

+3V0 RX

+3V0

CDC RX

VREF

DIG RX EN

DIG RX LE

RX DIG LD

DIG SYN SPI DO

DIG SYN SPI CLK

DIG RX NB EN

SYN RX OSC

SYN RX LO1

TX RX RF

Loop Filter

GND

Interface

Signal

Types:

analog

clock

digital

asynchronous serial data

synchronous serial data

Attenuator

CDC RX FE

TUNE

Summary of Contents for TB7100

Page 1: ...TB7100 base station Service Manual MBB 00005 01 Issue 1 October 2005...

Page 2: ...echnical Support E mail support taitworld com Website http support taitworld com To our European customers Tait Electronics Limited is an environmentally responsible company which supports waste minim...

Page 3: ...ct Codes 12 2 Mechanical Design 13 2 1 Tray 14 2 2 UI Board 14 2 3 Receiver Module 15 2 4 Transmitter Module 16 2 5 SI Board 17 3 Functional Description 19 3 1 Receiver Operation 20 3 1 1 RF Hardware...

Page 4: ...Interface Circuitry 58 4 8 Digital Board 60 5 Connections 63 5 1 External Connectors 64 5 2 Internal Connectors 68 5 2 1 Transmitter and Receiver Connectors 68 5 2 2 SI Board Connectors 71 5 2 3 UI B...

Page 5: ...nterface Fault Finding 137 11 Frequency Synthesizer Fault Finding 143 11 1 Initial Checks 144 11 2 Power Supplies 147 11 3 Phase locked Loop 155 11 4 Loop Filter 161 11 5 Receive VCO and Related Circu...

Page 6: ...ing 50W 40W 273 14 1 Power Supplies 276 14 2 Transmitter RF Power 285 14 3 Biasing of PA Driver and PAs 297 14 4 RF Signal Path 320 15 CODEC and Audio Fault Finding 343 15 1 Power Supplies 344 15 2 Fa...

Page 7: ...s manual describes the following hardware and software versions The IPNs internal part numbers of the transmitter and receiver boards are listed below the last two digits in the IPN represent the issu...

Page 8: ...r damage arising from use of the information contained in the manual or of the equipment and software it describes It is the responsibility of the user to ensure that use of such information equipment...

Page 9: ...t This alert is used to warn about the risk of equipment dam age or malfunction Note This alert is used to highlight information that is required to ensure that procedures are performed correctly Abbr...

Page 10: ...ier LO Local Oscillator LPF Low Pass Filter PA Power Amplifier PCB Printed Circuit Board PLL Phase Locked Loop PTT Press To Talk RISC Reduced Instruction Set Computing RSSI Received Signal Strength In...

Page 11: ...e This manual includes the information required for servicing the base station This section describes the different options available for frequency bands RF output power product codes For specificatio...

Page 12: ...40W 1 3 Product Codes This section describes the product codes used to identify products of the TB7100 base station product line The product codes of the TB7100 base station product line has the form...

Page 13: ...1U tray b The modules are secured by screws or clips into standoffs on the tray chassis and are easily removed for replacement The base station also includes two cooling fans f and a fan duct e in fr...

Page 14: ...UI board The rear panel has holes to accommodate the connectors and the fuse holder of the SI board the antenna connectors and a ground terminal For more information on the connections refer to Conne...

Page 15: ...frequency band and each RF output power configuration The RF b DC power c auxiliary d and user interface f connectors are located on the bottom side of the board The internal options connector e and...

Page 16: ...nd and each RF output power configuration The RF b DC power c auxiliary d and user interface f connectors are located on the bottom side of the board The internal options connector e and a factory con...

Page 17: ...12V DC b system connector labelled SYSTEM c serial data connector labelled IOIOI D The SI board has the following internal connectors two system interface connectors e to transmitter and receiver two...

Page 18: ...18 Mechanical Design TB7100 Service Manual Tait Electronics Limited October 2005...

Page 19: ...connector to and from the transmitter and receiver modules RS 232 data from the serial data connector IOIOI to and from the transmitter and receiver modules fan power and control from the SI board pow...

Page 20: ...ensure fan noise is not transferred to other sensitive system components If there is a fault in the fan circuitry the transmitter module is protected from overheating by its internal foldback circuitr...

Page 21: ...nsated crystal oscillator as a reference This ensures good centring of the IF filters and more consistent group delay performance The quadrature demodulator device has an internal frequency division o...

Page 22: ...ious channel spacings and data requirements These filters provide the bulk of adjacent channel selectivity for narrow band operation The filters have linear phase response so that good group delay per...

Page 23: ...whether de emphasis is required Several decoders may be active simultaneously Side Tones Side tones are summed in at the end of the audio processing chain These are tones that provide some form of ale...

Page 24: ...ap point T8 on the transmitter board the tap point is user selectable Analog Processing of Microphone Signal The CODEC AD6521 performs microphone selection and amplification The microphone amplifier c...

Page 25: ...s then applied The pre emphasised signal is hard limited to prevent over deviation and filtered to remove high frequency components The sample rate is then interpolated up to 48kHz and scaled to be su...

Page 26: ...e and VCO frequencies The net result is that the loop locks to a programmed multiple of the reference frequency The FCL generates an output of 13 012 0 004MHz Initially a VCXO produces a quasi regulat...

Page 27: ...ques to achieve fast frequency settling The frequency acquisition process of the FCL and RF PLL is able to occur concurrently with minimal loop interaction owing to the very large difference in freque...

Page 28: ...ontrol and monitoring Finally the output is low pass filtered to bring harmonic levels within specification Power Control The steady state power output of the transmitter is regulated using a hardware...

Page 29: ...table in custom logic memory that is played back at the correct rate to the DAC to produce the desired waveform The ramp up and ramp down waveforms are produced by playing back the look up table in fo...

Page 30: ...n one second Connectors and Circuit Boards There is an 18 way electrical interface between the UI board and the transmitter module and another from the UI board to the receiver module The physical con...

Page 31: ...ed Programming Application The programming application is a program on a PC that is connected to the base station via the PROG MIC connector on the user interface The programming application enables t...

Page 32: ...ystem interface provides internal power distribution serial data connection THSD or FFSK fan control general purpose IO receiver audio processing transmitter audio processing opto isolated keying rela...

Page 33: ...ol and Signaling 13v8 out RSSI RX GATE TX KEY RX INHIBIT RELAY DRIVER OPTO DIG IO TX DIG IO RX DIG IO AUX IO TX KEY AUX IO RX GATE RSSI Data and Fan Control 3v3 13v8 13v8 9v 4v5 3v3 13v8 out 13V8 GND...

Page 34: ...roprietary protocol that can be used with the base station This allows the base station configured in either data repeater or data modem modes to pass data speeds up to 12kbps on a narrow band channel...

Page 35: ...provide a relay driver output Both these options are configurable and these settings are discussed in the installation and operation manual 3 4 9 Fan Control There are three modes of operation for th...

Page 36: ...case are described below Dissipation of Heat from Transmitter The transmitter board is mounted directly onto a heatsink through which the forced air from the fans is ducted Dissipation of Heat from Re...

Page 37: ...Power supply connectors Fan Control Circuitry Microphone circuitry RS 232 circuitry Transmitter RF circuitry Transmitter digital logic Fans Digital board RX EX EX Ref Synths VCO s RF board Power suppl...

Page 38: ...38 Functional Description TB7100 Service Manual Tait Electronics Limited October 2005...

Page 39: ...odules The transmitter and receiver modules are divided into the following circuitry transmitter receiver frequency synthesizer including FCL CODEC and audio power supply interface digital board Figur...

Page 40: ...nd Audio Interface Digital Board RF Connector Power Connector Control Head Connector LPF 1 PIN Switch 1 Auxiliary Connector Internal Options Connector Main Board FPGA RISC Proc Serial Flash SRAM Flash...

Page 41: ...e power amplifier comprises the driver amplifier Q306 and two paralleled final devices Q309 and Q310 With the 50W 40W boards the signal from the exciter is amplified by Q306 to a power level of approx...

Page 42: ...and Level Shifter Crowbar Shaping Filter Tempera ture Sensor Buffer Amplifier TX RX RF Thermal Coupling OR Gate Switch TX INH 9V0 TX 13V8 BATT DIG TX INH DIG SYN EN SYN LOCK SYN TX LO Power Supply Di...

Page 43: ...wer control loop senses the forward power by means of the diode D304 This signal is fed to the buffer and a band limited operational amplifier back to the gate of Q306 A voltage clamp one of the opera...

Page 44: ...ge consists of a crystal channel filter BPF1 followed by an IF amplifier and then another crystal filter BPF2 The second mixer is an IC quadrature mixer with an internal AGC amplifier This IC has a di...

Page 45: ...DEC and Audio Digital Board PLL Noise Blanker VHF only Switch VHF only Transmitter Frequency Synthesizer Mixer Receiver VCO CDC RX PIN AGC CDC RX AGC RX CDC QN RX CDC QP RX CDC IN RX CDC IP 3V0 RX 3V0...

Page 46: ...hat the channel filtering is centred thereby minimizing distortion Received Signal Strength Indication The RSSI is calculated in the FPGA and DSP and can be passed as an analog voltage to the internal...

Page 47: ...regulator output voltage is electrically noisy however and filtering is essential Filtering of the power supply is achieved with two capacitance multipliers Q508 and C585 for the VCO supply and Q512 a...

Page 48: ...LPF Mixer VCXO TCXO Modulator Buffer Amplifier PLL MOD VCO 2 VCO 1 Buffer Amplifiers and Coupler 5 V Switch TR Switch VCO UHF only 6V0 AGND 3V0 AN Power Supply CDC VCXO MOD SYN CDC FCL SYN CDC LFV CD...

Page 49: ...mpares the 25kHz reference and the divided VCO signal and the error is used to control the internal charge pump The charge pump is a current source that can sink or source current in proportion to the...

Page 50: ...s implemented in hardware under software control in conjunction with use of the synthesized reference input The result is a transmit receive settling time of less than 4 5ms The switching time is meas...

Page 51: ...nce frequency Circuit Operation The VCXO output is mixed with the TCXO output to create a nominal difference or offset frequency SYN CDC FCL of 12 0kHz The signal SYN CDC FCL is fed via the CODEC IC50...

Page 52: ...and Q outputs IRXP IRXN QRXP and QRXN balls of the receiver s second IF stage The analog signals are differential and biased at 1 2V nominally The digital section communicates with this CODEC via a tw...

Page 53: ...FCL Digital Board AGND 13V8 BATT 2V5 CDC 9V0 3V3 3V0 AN CDC RX AUD AUD ITF SPK AUD ITF SPK ITF RX BEEP IN ITF CH MIC AUD ITF AUX MIC AUD ITF VOL WIP DC CDC AUD TAP OUT CDC RSSI ITF AUD TAP IN CDC2 DIG...

Page 54: ...R252 and R253 ensure stability of the amplifier at high frequencies When operational the output bias voltage for IC202 is approximately half the base station supply voltage When not operational the o...

Page 55: ...er formed by IC201 pins 1 to 3 R219 R220 R221 R224 C206 C208 and C210 is a third order Butterworth type with a cut frequency of approximately 12kHz The output of the low pass filter is amplified by 6d...

Page 56: ...for the protection of internal devices which have an operating voltage of less than 30V The ADC also ensures protection if the base station operates outside its specified voltage range of 10 8V to 16V...

Page 57: ...ch 3V3 2V5 Regulator 3 V Rx Switch PSU Super visor 13V8 Switch Reverse Polarity Protection 13V8 BATT 9V0 TX 9V0 3V0 AN 13V8 BATT 9V0 3V0 AN 3V3 2V5 CDC 3V0 AN 3V0 RX DIG RX EN DIG TX EN DIG SLP EN 3V3...

Page 58: ...limiting action The current limit value is approximately 18mA the inverse of the value of R761 The output configuration is open collector with a pull up to 3 3V by default Pull up options to 5V and 13...

Page 59: ...AGND DGND SPK SPK VOL WIP DC CH MIC AUD RX AUD CH ON OFF CH RXD CH TXD CH PTT CH GPIO1 CH SPI DI CH SPI DO CH SPI CLK CH LE RX AUD RX BEEP IN AUD TAP OUT AUD TAP IN AUX MIC AUD RSSI 13V8 SW IOP GPIO1...

Page 60: ...intended for connection to internal digital devices and so these have relatively light protection Hookswitch Detection Hookswitch detection is performed by Q700 R709 R706 and R712 When the resistance...

Page 61: ...GND AGND DIG CH SPI CLK DIG CH SPI DO ITF CH SPI DI DIG CH LE ITF CH GPI1 DIG CH GPO1 ITF CH PTT ITF CH HOOK ITF ON OFF ITF IOP GPIO1 7 DIG IOP TXD ITF IOP RXD ITF AUX GPI1 7 DIG AUX GPO4 7 DIG AUX TX...

Page 62: ...62 Circuit Descriptions TB7100 Service Manual Tait Electronics Limited October 2005...

Page 63: ...L5 PL6 13V8DC Internal DC input J600 ARM7 programming J202 J105 13V8DC input connector Serial interface connector J104 System interface connector J106 DC power Temp signal Received audio signal RF SK1...

Page 64: ...e base station via a readily accessible disconnect device such as a fuse or DC rated circuit breaker with the appropriate rating as shown in the table below The DC input leads should be of a suitable...

Page 65: ...e base station The RF output is via the TX ANT connector N type on the rear panel of the base station The RF connector is an N type connector with an impedance of 50 Important The maximum RF input lev...

Page 66: ...utput DC signal 10 Tx digital in out 1 input output output high 3 1 V no load low 0 6 V 10mA sink input high 1 7 V low 0 7 V 11 Tx audio input audio input 12 Tx digital in out 2 input output output hi...

Page 67: ...ction to the base station Programming Microphone PROG MIC Pin Signal Name Signal Type Notes 1 not connected not used 2 receive data output data transmitted by TB7100 3 transmit data input data receive...

Page 68: ...receiver RF Connectors The RF connectors of the transmitter and the receiver are N type connectors with an impedance of 50 DC Power Connectors The DC power connectors of the transmitter and the recei...

Page 69: ...Pin Signal Name Signal Type Notes Transmitter Receiver 1 RX AUD no connection no connection no connection 2 13 8VDC no connection output 13V8DC for UI board 3 CH TXD input input programming data 4 CH...

Page 70: ...Signal Name Signal Type Notes 1 Tx and Rx 13 8VDC output 2 Tx and Rx ground output external view Pin Signal Name Signal Type Notes 1 TX_AUX_GPIO7 output Tx key signal 2 TX_AUX_GPIO6 bidirectional dig...

Page 71: ...ctional digital input output 3 RX_AUX_GPIO5 bidirectional digital input output 4 RX_AUX_GPIO4 bidirectional digital input output 5 RX_AUX_RXD input data 6 RX_AUX_TXD output data 7 RX_AUX_GPI3 input di...

Page 72: ...WIP_DC output no connection 11 TX_CH_SPI_D0 input 12 TX_CH_LE input 13 TX_CH_SPIO1 input digital ground 14 TX_ 3V3 no connection no connection 15 TX_CH_SPI_DI output 16 TX_CH_SPI_CLK input 17 TX_CH_SP...

Page 73: ...controlled test mode CCTM 6 1 Repair Levels and Website Access Repair Levels This manual covers level 1 and level 2 repairs of the base station Level 1 repairs comprise the replacement of transmitter...

Page 74: ...s may carry out level 1 and level 2 repairs whether under warranty or not Skills and Resources for Level 1 Repairs For level 1 repairs basic electronic repair skills are sufficient Apart from the stan...

Page 75: ...on is published on the Technical Support website Tait FOCUS Database An additional source of information to service centres is the Tait FOCUS call logging database This is accessible on the Technical...

Page 76: ...that a hot air tool affords little control Even in skilled hands use of a hot air tool to remove cans will result in rapid uncontrolled rises in the temperature of components under the can being remov...

Page 77: ...n a screw or nut in the base station Under torquing can cause problems with microphonics and heat transfer Over torquing can damage the base station The illustrations in Disassembly and Reassembly on...

Page 78: ...and Transport of Items Always observe anti static precautions when storing shipping or carrying the circuit boards and their components Use anti static bags for circuit boards and anti static bags or...

Page 79: ...age of the transmitter Important While servicing the transmitter module avoid overheating during test transmissions The heatsink must be secured to the transmitter board After completing any measureme...

Page 80: ...tor of the CTU to the SYSTEM connector of the base station using the TB7100 CTU adapter and the 25 way D range ribbon cable Audio connections between the CTU and test equipment are described in the re...

Page 81: ...BNC power connector 25 way D range ribbon cable TBA0STU TMAA20 04 cable T950 001 USB1 1 to serial DB9 adapter optional RF comms set Test PC Oscilloscope DC power supply Transmitter Receiver SI board A...

Page 82: ...station the switches have no effect although it is good practice to set the MODE switch to RX Transmit tests Receive tests Switch Position Switch Position HOOK OFF HOOK HOOK OFF HOOK MODE RX initially...

Page 83: ...monitor out BNC AUDIO IN HI BNC AUDIO OUT BNC RF in out N type DC power connector TMAA23 02 cable 50W 40W board TMAA20 03 cable 25W board TMAA21 01 cable TOPA SV 024 Transmitter or receiver module T95...

Page 84: ...information for the board consult the BOM for the board Identify the component in question in the BOM Note however that a new PCB information is published only whenever there is a major change in the...

Page 85: ...side of the transmitter and receiver boards are identified in Figure 6 4 and Figure 6 5 The figures also show the locations of the connectors Figure 6 4 Shielding cans and connectors top side Digital...

Page 86: ...the documentation supplied with the tool for the correct procedures If the tool is not available a hot air tool may be used instead However technicians require training in the best techniques to emplo...

Page 87: ...d techniques and these are discussed below Another issue of concern is the procedure for removing and installing cans A discussion of the issue concludes this section Non standard Procedures Do not us...

Page 88: ...ted October 2005 Figure 6 6 Locations of the capacitors C548 and C565 and the inductors L601 and L602 top side VHF board UHF board similar Note that other components may be fitted for C548 such as C50...

Page 89: ...f HyperTerminal click Start Programs Accessories Communications HyperTerminal 2 In the terminal program first select the COM port to which the module is connected Then select the following settings fo...

Page 90: ...y 1 on 2 mute None 110 Audio volume Sets the level of the audio volume 110 x where x defines the required level any integer from 0 to 255 None 138 Select microphone Selects the microphone required 138...

Page 91: ...character identifier and y is an eight digit version number 133 Hardware version Reads the product code of the module and the hardware version number 133 x y where x is the product code and y is the...

Page 92: ...e with results of calibration attempt 334 Synthesizer power Switches the frequency synthesizer on or off via the DIG SYN EN line 334 x where x is the required state 0 off 1 on None 335 Synthesizer swi...

Page 93: ...0 to 1023 114 x to set value where x is the required power setting an integer from 0 to 1023 None 304 Driver bias Sets or reads the clamp current at the gate of the PA driver 304 to read value x where...

Page 94: ...alue where x is the DAC value of the required bias voltage any integer from 0 to 255 None 332 Final bias 2 Sets or reads the bias voltage for the second PA 332 to read value x where x is the DAC value...

Page 95: ...up again and place the module in CCTM again C05 The module has not responded within the specified time Re enter the CCTM command X04 The DSP is not responding Check the DSP pin connections If the err...

Page 96: ...and operation manual Audible indications are provided in the form of different tones emitted from the speaker Note The base station does not generate audible signals Table 6 8 Visual indications provi...

Page 97: ...lace the defective parts Inspect all disassembled parts for damage and replace them if necessary Observe the torque settings indicated in the relevant figures For information on spare parts refer to S...

Page 98: ...e base station to disconnect the base station from DC power 2 Use a Philips 2 screwdriver to disconnect the cables from the DC power connector e 3 Disconnect the antenna connectors for transmit and re...

Page 99: ...the rear of the base station until the volume control shaft clears the front panel Lift the UI board clear of the chassis 6 Disconnect the two Micro MaTch connectors e Fitting 1 Plug the two Micro Ma...

Page 100: ...eiver module There is no heat transfer plate on the receiver Check that the replacement module has links LK2 LK3 and LK4 not fitted as shown above Fitting Note Before fitting the receiver module make...

Page 101: ...of the tray chassis Fitting Note Although the transmitter and receiver modules look alike a transmitter module can not replace a receiver module There is no heat transfer plate on the receiver Check t...

Page 102: ...itter Module on page 103 2 Use a Torx T10 screwdriver to unscrew the seven screws f and g together with the spring washers and flat washers 3 Lift the transmitter module clear of heat sink 4 Remove an...

Page 103: ...1 Remove any residue of the gap pad s from the underside of the board and the heatsink Make sure that the heatsink and the heat plates are free of any dust Peel off the transparent film on one side of...

Page 104: ...pply 0 1cm3 of thermal paste over the complete contact surface on the tin plated copper plate refer to Figure 7 6 on page 105 Important With the 50W 40W board the rectangular gap pad j must not overla...

Page 105: ...SI board towards the front of the base station until the connectors b c and d clear the rear panel Lift the SI board clear of the chassis Fitting 1 Slide the SI board into the tray chassis by fitting...

Page 106: ...the fan duct d 4 Use a PZ1 Pozidriv screwdriver to remove the two M3 25mm screws e and remove the fan Fitting 1 Place the fan into position on the fan duct e and use a PZ1 screwdriver to fasten the t...

Page 107: ...he fan power board c to the fan duct d 3 Fitting is carried out in reverse order 7 10 Replacing the Temperature Sensor Board Note The temperature sensor board is manufactured as part of the SI board a...

Page 108: ...nected correctly as shown below 2 Place the tray cover onto the chassis 3 Use a Torx T10 torque driver to fasten the tray cover with the 15 countersunk screws to 4 5lb in 0 5N m 4 Fit the fuse b at th...

Page 109: ...sks The following tasks need to be carried out initial administration visual inspection power up the base station read the programming files read the calibration files check any error messages check t...

Page 110: ...powered from the receiver module If the receiver module is faulty and does not power up then there will be no indication that the transmitter module has powered up correctly If during these tests the...

Page 111: ...e Only the UI cable to the receiver needs to be connected but ensure the TX RX switch is set to RX Tip Instead of the spare UI board a TMAC20 0T control head can be connected to the receiver module 9...

Page 112: ...the test PC before going to Step 5 5 If both programming files could be read load default test files to the receiver and transmitter modules and go to Task 5 6 If none of the programming files could...

Page 113: ...receiver or transmitter module load a default file verify that the module can be read and return to Step 1 receiver or Step 3 transmitter Task 5 Read the Calibration File Use the calibration applicat...

Page 114: ...om the tray chassis Just unplug the connectors 5 If the transmitter keys up now the original transmitter module is faulty Reconnect the original transmitter module and go to Task 9 Then continue with...

Page 115: ...lue agrees with the programmed settings go to Step 8 If it does not attempt to complete the required transmitter audio level adjustment as described in the installation and operation manual 6 If this...

Page 116: ...smit ter listed in Transmitter Issues on page 81 Synthesizer Out of Lock 1 Use CCTM command 101 x y 0 to set the transmit frequency to the bottom of the band 2 Use CCTM command 33 to set the base stat...

Page 117: ...e to the receiver module Note When checking the receiver module only the UI cable to the receiver needs to be connected but ensure the TX RX switch is set to RX 4 If this rectifies the fault go to Tas...

Page 118: ...Receive or Receive Audio 1 Use CCTM command 101 x y 0 to set the receive frequency to the bottom of the band 2 Use CCTM command 72 to read the lock status 3 If the synthesizer is in lock go to Step 5...

Page 119: ...Task 10 speaker and volume potentiometer go to Speaker or Volume Potentiometer Faulty below 3 Replace the UI board if necessary Speaker or Volume Potentiometer Faulty If the speaker functions only int...

Page 120: ...aulty fan s If not replace the fan power board 4 Set the jumpers on the SI board to match the settings below J206 1 2 J207 1 2 5 With the transmitter module connected to a suitable load check that fan...

Page 121: ...nt and re calibrate the module Refer to the online help of the calibration application 4 Use the programming and application to load the programming and files read or set up in Initial Tasks 5 Use the...

Page 122: ...al Administration The final administration tasks are the standard workshop procedures for updating the fault database and returning the repaired base station to the Customer with confirmation of the r...

Page 123: ...miter 4 0 kHz to 5 0 kHz Max deviation kHz Un balanced output Level Limit 1 r r 0 15 VPP ZL 10k TL Vp p 20dB step balanced input audio freq kHz Mute Gating RF levels Mute dBm Unbalanced deviation TD 1...

Page 124: ...126 Servicing Procedures TB7100 Service Manual Tait Electronics Limited October 2005...

Page 125: ...sks are applicable depends on the nature of the fault radio fails to power up power up option has failed external power at connector has failed With the first fault either the radio fails to power up...

Page 126: ...ial Tasks on page 111 If it does not go to Step 5 5 Check the digital power up signal at pin 5 of IC602 see Figure 9 1 the signal is active high namely when the voltage exceeds 2 0V DC Measure the vol...

Page 127: ...Power Supply Fault Finding 129 Tait Electronics Limited October 2005 Figure 9 1 Important components of the power supply circuitry bottom side including 3 3V regulator IC602 pin 7 pin 5 C603 C618 R19...

Page 128: ...ting the supply or preventing the radio from powering up While keeping the ON OFF key depressed measure the supply at the 3V3 test point near the corner of the digital board see Figure 9 2 The voltage...

Page 129: ...ault remains the repair failed replace the main board assembly and go to Final Tasks on page 123 6 Reconnect the 13 8V supply Press the ON OFF key If the radio powers up return to Initial Tasks on pag...

Page 130: ...relevant regulator IC Repair any fault 2 If the regulator IC has been removed resolder it in position 3 Reconnect the 13 8 V supply and press the ON OFF key If the radio powers up or the correct regul...

Page 131: ...power sense IOP GPIO7 auxiliary power sense AUX GPI3 emergency power sense AUX GPI2 4 For the first two lines confirm that the Power Sense Ignition option has been selected in the Action field and Hig...

Page 132: ...PL100 Repair any fault and go to Step 5 2 For the auxiliary power sense option the link LK2 should be inserted see Figure 9 2 Connect 3 3V DC more than 2 6V to be precise from the power supply to the...

Page 133: ...is high Remove the 3 3V supply and ground the IOP GPIO7 line to be precise the voltage on the line should be less than 0 6V If the power up signal is now low conclude with Step 5 If it is not check f...

Page 134: ...rst confirm the link settings required and then carry out the following procedure 1 With the radio powered up confirm that 13 8V DC is present at pin 3 of IC605 see Figure 9 1 and more than 3V DC at p...

Page 135: ...enclosures In Figure 10 1 which shows part of the internal options connector as an example IOP GPIO7 is a connector signal and ITF IOP GPIO7 is an internal signal Types of Signals The connector and in...

Page 136: ...vice Manual Tait Electronics Limited October 2005 Figure 10 2 Components of the interface circuitry top side near the CDC TOP and IF TOP cans Figure 10 3 Components of the interface circuitry top side...

Page 137: ...ck or vibration or to a temperature change This might expose any intermittent contact in which case go to Step 3 3 If the expected signal is not present check whether the expected internal signal is p...

Page 138: ...140 Interface Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005 Figure 10 4 Components of the interface circuitry bottom side...

Page 139: ...to Step 8 7 The fault lies with the radio s internal circuitry If the power supply circuitry or the CODEC and audio circuitry is suspect continue with the fault diagnosis as in Power Supply Fault Find...

Page 140: ...142 Interface Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005...

Page 141: ...91 Use an oscilloscope with a x10 probe for all voltage measurements required The signals should appear stable and clean Consider any noise or unidentified oscillations as evidence of a fault requirin...

Page 142: ...ault will be implied by one of the following consequences radio fails to receive or receive performance is degraded radio fails to enter transmit mode radio exits transmit mode unexpectedly radio ente...

Page 143: ...smit VCO The response will be one of the three messages listed in Step 2 The first two messages will be preceded by eight calibration values Reset the radio and re enter CCTM 5 If the calibration succ...

Page 144: ...0 where x is the frequency in hertz 3 Enter the CCTM command 72 to determine the lock status in receive mode Note the response The action required depends on the lock status as described in the follow...

Page 145: ...DC supply from 3 V regulator in PSU module 3V0 AN The measurement points for diagnosing faults in the power supplies are summarized in Figure 11 1 Figure 11 1 Measurement points for the frequency synt...

Page 146: ...go to Step 5 5 Check the 9 V supply at Q500 and R533 see Figure 11 3 6 If the voltage is correct go to Step 7 If it is not the 9V regulator IC601 is suspect go to Task 3 of Power Supply Fault Finding...

Page 147: ...ding 149 Tait Electronics Limited October 2005 Figure 11 2 Synthesizer circuitry under the SYN TOP can and the 6 V regulator IC606 top side B1 band H5 H6 bands Measurement point on L506 pin not used P...

Page 148: ...150 Frequency Synthesizer Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005 Figure 11 3 Synthesizer circuitry under the FCL TOP can top side SYN TOP CAN...

Page 149: ...01 is suspect go to Task 3 of Power Supply Fault Finding on page 132 4 If the input to the regulator IC606 is correct but not the output check IC606 see Figure 11 2 and the associated circuitry if nec...

Page 150: ...requency Synthesizer Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005 Figure 11 4 Synthesizer circuitry under the SYN BOT and VCO BOT cans bottom side B1 band H5 H6 bands Q511...

Page 151: ...nd the 5V and transmit receive switches based on Q506 Q507 and Q508 pins 1 2 6 see Figure 11 2 Replace any suspect transistor Conclude with Step 6 5 With a VHF radio check for faults in the C multipli...

Page 152: ...ply at L506 see Figure 11 2 The measurement point is the via shown in the figure 4 If the voltage is correct go to Step 5 If it is not the 3 V regulator IC603 is suspect go to Task 3 of Power Supply F...

Page 153: ...d output are summarized in Figure 11 5 Task 7 Supply for Charge Pump First check the supply for the charge pump of the PLL 1 Measure the supply for the charge pump at pin 16 of IC503 see Figure 11 2 2...

Page 154: ...ER AT C565 TP503 JUNCTION OF R566 AND R570 TP503 JUNCTION OF R566 AND R570 SIGNAL TYPES RF ANALOG CLOCK DIGITAL PLL LOOP FILTER AND SUMMER FILTERING OF SUPPLY FOR PLL AND LOOP FILTER FCL VCO CIRCUITRY...

Page 155: ...n 8 of IC503 see Figure 11 2 2 If the signal is correct go to Task 9 If it is not go to Step 3 3 Check IC503 see Figure 11 2 Replace IC503 if it is suspect 4 Determine if the fault has been removed If...

Page 156: ...6 Enter the CCTM command 334 1 to switch on the synthesizer and measure the voltage at the via between R104 see Figure 11 6 and the digital board 7 If the voltages measured in Step 5 and Step 6 are s...

Page 157: ...o Loop Filter on page 161 If it is not go to Step 4 4 Check for continuity between pin 14 of IC503 and the digital board via R568 see Figure 11 2 and L102 see Figure 11 6 5 If there is a fault go to S...

Page 158: ...er Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005 Figure 11 7 Synthesizer circuitry under the SYN TOP can top side B1 band H5 H6 bands Q512 Q512 Junction of C541 and R547 Ju...

Page 159: ...R542 see Figure 11 7 3 Using an oscilloscope proceed as follows to observe the voltage at C565 before and after grounding the junction between C541 and R547 see Figure 11 7 While holding the oscillosc...

Page 160: ...rror or a transmit fault the transmit VCO is suspect go to Transmit VCO and Related Circuitry UHF Radios on page 175 Task 13 Check Reference Voltage If the loop filter circuitry is suspect first check...

Page 161: ...the voltage is correct resolder R542 in position see Figure 11 7 and go to Task 15 3 Check IC504 IC505 Q511 see Figure 11 4 C5085 to C5089 B1 band see Figure 11 7 or C5085 and C5086 H5 H6 bands see Fi...

Page 162: ...the digital board see Figure 11 6 The result should be 9 Enter the CCTM command 389 0 to set the mode to slow 10 Measure the voltage at the via between R105 and the digital board see Figure 11 6 The...

Page 163: ...5085 and C5086 H5 H6 bands see Figure 11 7 and associated components Conclude with Step 9 4 Remove R566 and R570 see Figure 11 7 which provide a modulation path to the VCO s 5 Repeat the measurement o...

Page 164: ...related circuitry The minimum and maximum receive frequencies for the different UHF frequency bands are defined in Table 11 2 There are six aspects Task 17 check receive VCO Task 18 repair PLL feedbac...

Page 165: ...PORT PIN 4 OF IC5100 PIN 4 OF IC5100 SIGNAL TYPES RF ANALOG CLOCK DIGITAL PLL LOOP FILTER AND SUMMER FILTERING OF SUPPLY FOR VCO CIRCUITRY FREQUENCY SYNTHESIZER PLL FEEDBACK LOOP VOLTAGE RECEIVE VCO...

Page 166: ...aximum given in Table 11 2 3 If the receive frequency measured in Step 2 is correct go to Step 4 If it is incorrect go to Task 19 but if no frequency is detected go to Task 20 4 Proceed as follows to...

Page 167: ...Frequency Synthesizer Fault Finding 169 Tait Electronics Limited October 2005 Figure 11 9 Synthesizer circuitry under the SYN TOP and VCO TOP cans UHF radio top side Tx port Junction of C541 and R547...

Page 168: ...ove the VCO BOT can 3 Replace the components C567 R574 see Figure 11 10 and IC503 see Figure 11 9 4 Also check the second stage of the receive buffer amplifier based on IC5100 see Figure 11 10 Repair...

Page 169: ...receive VCO The circuitry is based on Q504 see Figure 11 9 3 If a fault is found repair it and go to Step 4 If no fault is found go to Step 6 4 Repeat the frequency measurements in Step 2 and Step 4 o...

Page 170: ...2 Enter the CCTM command 335 0 to switch on the supply to the receive VCO 3 Measure the voltage at the first collector pin 3 of Q506 see Figure 11 9 The voltage should be 4 Enter the CCTM command 335...

Page 171: ...R103 and the digital board 6 If the voltages measured in Step 4 and Step 5 are correct go to Step 7 If they are not the digital board is faulty resolder R103 in position see Figure 11 6 replace the m...

Page 172: ...e CCTM command 335 1 to set the transmit receive switch on 5 Again measure the voltages of Q5100 and IC5100 6 If the voltages are correct the receive VCO is suspect go to Step 7 If they are not the re...

Page 173: ...ansmit VCO and related circuitry The minimum and maximum transmit frequencies for the different UHF frequency bands are defined in Table 11 3 There are five aspects Task 23 check transmit VCO Task 24...

Page 174: ...maximum given in Table 11 3 3 If the transmit frequency measured in Step 2 is correct go to Step 4 If it is incorrect go to Task 25 If no frequency is detected go to Task 26 4 Proceed as follows to ob...

Page 175: ...assembly and go to Final Tasks on page 123 Task 25 Repair Transmit VCO If either or both the minimum and maximum transmit frequencies are incorrect the transmit VCO circuitry is faulty 1 Remove the V...

Page 176: ...2 Enter the CCTM command 335 1 to switch on the supply to the transmit VCO 3 Measure the voltage at the second collector pin 6 of Q506 see Figure 11 9 The voltage should be 4 Enter the CCTM command 33...

Page 177: ...ransmit buffer amplifier in transmit mode Enter the CCTM command 335 1 to set the transmit receive switch on 5 Again measure the voltage at Q5001 6 If the voltages are correct the transmit VCO is susp...

Page 178: ...pply only to VHF radios the VHF frequency bands are defined in Table 11 4 There are six aspects Task 28 check VCO Task 29 repair PLL feedback Task 30 repair VCO Task 31 check transmit receive switch T...

Page 179: ...OF D5004 PIN 2 OF D5004 TX PORT TX PORT RX PORT RX PORT SIGNAL TYPES RF ANALOG CLOCK DIGITAL PLL LOOP FILTER AND SUMMER FILTERING OF SUPPLY FOR VCO CIRCUITRY FREQUENCY SYNTHESIZER PLL FEEDBACK VCO BUF...

Page 180: ...aximum given in Table 11 4 3 If the maximum frequency measured in Step 2 is correct go to Step 4 If it is incorrect go to Task 30 but if no frequency at all is detected go to Task 31 4 Enter the CCTM...

Page 181: ...rvice Manual Frequency Synthesizer Fault Finding 183 Tait Electronics Limited October 2005 Figure 11 12 Synthesizer circuitry under the SYN TOP can VHF radio top side Tx port Junction of C541 and R547...

Page 182: ...pect 1 Resolder R542 in position see Figure 11 12 2 Remove the VCO BOT can 3 Replace the components L510 see Figure 11 13 and IC503 see Figure 11 12 4 Confirm that the fault in the radio has been remo...

Page 183: ...3 3 If a fault is found repair it and go to Step 4 If no fault is found go to Step 7 4 Repeat Step 1 and Step 2 of Task 28 to measure the maximum VCO frequency 5 Repeat Step 4 and Step 5 of Task 28 to...

Page 184: ...age at pin 2 of D5004 7 If the voltages measured in Step 4 and Step 6 are correct go to Step 8 If they are not the switching network is suspect go to Task 32 8 Enter the CCTM command 335 1 to switch o...

Page 185: ...and the digital board 6 If the voltages measured in Step 4 and Step 5 are correct go to Step 7 If they are not the digital board is faulty resolder R103 in position see Figure 11 6 replace the main bo...

Page 186: ...13 Some RF noise might be observed 3 Measure the voltage at pin 1 of Q5001 see Figure 11 13 4 If the voltages measured in Step 2 and Step 3 are not correct go to Step 5 If they are check the VCO circ...

Page 187: ...with the reference frequency input from the FCL to the PLL will imply that the FCL is suspect Fault diagnosis of the FCL is divided into four stages check power supply check VCXO and TCXO outputs che...

Page 188: ...FIER AGND DIGITAL BOARD CDC VCXO MOD SYN CDC FCL BUFFER AMPLIFIER INTERFACE CIRCUITRY RECEIVER FCL CIRCUITRY 3V0 AN SUPPLY C536 R541 VCXO OUTPUT AT C536 VCXO OUTPUT AT C536 PLL SYN RX OSC C510 TP504 F...

Page 189: ...sembly from the chassis and place the radio in CCTM 2 Measure the supply 3V0 AN at the via shown in Figure 11 15 The via is adjacent to the CDC TOP can 3 If the voltage is correct go to VCXO and TCXO...

Page 190: ...t to C536 see Figure 11 16 The signal should be 2 If the signal is correct go to Task 36 If it is not go to Step 3 3 The VCXO circuitry under the VCXO BOT can is faulty Remove the VCXO BOT can 4 Locat...

Page 191: ...esizer Fault Finding 193 Tait Electronics Limited October 2005 Figure 11 16 FCL circuitry under and adjacent the FCL TOP can VIA FOR MEASURING VCXO OUTPUT POSITION IN WHICH TO PLACE R527 FOR FAULT DIA...

Page 192: ...at TP501 and TP502 on page 195 If it is not go to Step 3 3 The TCXO circuitry under the CDC TOP can is faulty Remove the CDC TOP can 4 Locate and repair the fault in the TCXO XL500 and associated com...

Page 193: ...ference frequency at the TP502 test point see Figure 11 16 The signal is SYN CDC FCL and should be 2 If the signal is correct go to Task 38 If it is not go to Step 3 3 The mixer or LPF circuitry under...

Page 194: ...t there is a fault in the modulator buffer amplifier IC502 pins 1 to 3 and associated components see Figure 11 16 Rectify the fault and return to Step 1 5 Connect the TP501 test point to ground by res...

Page 195: ...IC501 see Figure 11 16 should be Also the VCXO input to the mixer at R522 pin 1 of IC501 see Figure 11 16 although noisy and difficult to measure should be 5 Confirm the removal of the fault and go to...

Page 196: ...aults were rectified perform the following CCTM checks 1 Enter the CCTM command 393 1 1900 Measure the voltage level at the TP501 test point see Figure 11 16 2 Enter the CCTM command 72 and note the l...

Page 197: ...remove the VCXO BOT can 2 Locate and repair the fault in the VCXO tank circuit Q501 D501 D502 XL501 and associated components see Figure 11 17 3 Confirm the removal of the fault and go to Step 4 If t...

Page 198: ...f there are faults such as open circuits in the connections repair the circuitry and repeat Task 40 If the connections are not faulty then the digital board is faulty Replace the main board assembly a...

Page 199: ...f the receiver sensitivity is low begin with Faulty Receiver Sensitivity on page 202 to determine the extent of the loss in sensitivity CCTM Commands The CCTM commands required are listed in Table 12...

Page 200: ...lt 1 Input an RF signal not necessarily modulated of 90 dBm or 84 dBm with a trigger base radio at the RF connector 2 Enter the CCTM command 378 to measure the receiver output level 3 Note the value x...

Page 201: ...Service Manual Receiver Fault Finding 203 Tait Electronics Limited October 2005 Figure 12 1 Receiver circuitry under the IF TOP can top side Q404 H5 H6 bands Measurement point B1 band Q404 Measurement...

Page 202: ...lies First check the two power supplies 3V0 AN and 3V0 RX for the receiver circuitry 1 Remove the main board assembly from the chassis 2 Check for 3 0V DC 3V0 AN at the TP601 test point near the LO2 B...

Page 203: ...er Fault Finding 205 Tait Electronics Limited October 2005 Figure 12 2 Receiver circuitry under the LO2 BOT can bottom side H5 H6 bands B1 band Figure 12 3 Receiver circuitry under the FE TOP can top...

Page 204: ...age 123 4 Recalibrate the receiver using the calibration application 5 Confirm the removal of the fault and go to Final Tasks on page 123 If the repair failed go to Task 7 Task 4 Check Lock Status If...

Page 205: ...and go to Step 7 7 Recalibrate the receiver using the calibration application 8 Confirm the removal of the fault and go to Final Tasks on page 123 If the repair failed go to Task 7 Task 6 Check Match...

Page 206: ...ning circuitry Open the Raw Data page and click the Receiver tab 2 Record the values listed in the Rx FE Tune BPF Settings field these are the DAC values of the FE front end tuning voltages for the fi...

Page 207: ...in Step 2 to Step 5 reveal no fault go to Step 7 If there is a fault repair it and go to Step 8 7 Check the signal level at the output of LO1 and continue the fault diagnosis as in Power Supply for FC...

Page 208: ...3 3 Check the IF amplifier bias conditions as in Step 4 and Step 5 of Task 5 4 Check the LNA bias conditions as in Step 4 and Step 5 of Task 8 5 If the checks of Step 2 to Step 4 reveal no fault go to...

Page 209: ...ion open the Raw Data page and click the Receiver tab 2 Note the settings listed in the AGC Voltage Cal Pts field The nominal settings should be as listed in Table 12 3 3 If the settings are correct g...

Page 210: ...tween 0dBm and about 3dBm 2 If the values are as expected go to Task 13 If they are not go to Step 3 3 Recalibrate the receiver and check the values again 4 If the values are now correct go to Step 5...

Page 211: ...libration application for Task 15 and Task 16 Task 14 Determine Type of Muting Selected First use the programming application to determine the type of muting selected 1 In the programming application...

Page 212: ...tab 4 Compare the values in the Mute Noise Readings field with the required minimum and maximum values listed in Table 12 4 5 If the mute noise readings are correct go to Task 1 and check the receive...

Page 213: ...ning Pt fields and the Hysteresis fields under the Squelch Thresholds label are what the Customer expects 3 If the calibration values are as expected go to Task 10 and check the RSSI calibration If th...

Page 214: ...ion application to check the TCXO calibration Open the Raw Data page and click the Volt Ref TCXO VCO VCXO tab 2 Note the values listed in the Tx TCXO and Rx TCXO fields of the TCXO group box The value...

Page 215: ...1 The frequency is the second IF and should be 3 If the second IF is correct go to Step 6 If it is not go to Step 4 4 Recalibrate the TCXO 5 Check if the distortion fault has been removed If it has go...

Page 216: ...218 Receiver Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005...

Page 217: ...olled Test Mode CCTM on page 91 Table 13 1 CCTM commands required for the diagnosis of faults in the transmitter Command Description 32 33 47 101 x y 0 114 x 304 304 x 318 319 326 x 331 331 x 332 332...

Page 218: ...elding the bulk of the transmitter circuitry PAD TOP PAF TOP DIRC TOP PIN TOP LPF TOP To remove any can first remove the main board assembly from the chassis In the case of the PAD TOP and PAF TOP can...

Page 219: ...ssembly will be connected to the RF communications test set as shown in on page 82 But for those tests where this connection is not necessary a 50 load may be used instead Do not operate the transmitt...

Page 220: ...in PSU module 9V0 TX The measurement and test points for diagnosing faults in the power supplies are summarized in Figure 13 1 Figure 13 1 Measurement and test points for diagnosing faults involving...

Page 221: ...nter the CCTM command 326 5 to set the radio to maximum power 5 Attempt to place the radio in transmit mode Enter the CCTM command 33 6 If the radio enters the transmit mode continue with Step 7 If in...

Page 222: ...smitter Fault Finding 25W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 13 2 Point for measuring the power supply to the PAs H5 H6 BANDS B1 BAND MEASUREMENT POINT ON L310 B1 BAND...

Page 223: ...imited October 2005 Figure 13 3 Point for measuring the power supply to the PA driver B1 band H5 H6 bands Measurement point on L306 Measurement point on R339 Point 2 on R350 Point 1 on R350 Measuremen...

Page 224: ...7 Remove the heat transfer block from the main board Replace Q311 situated on the bottom side of the main board next to the power connector Replace the heat transfer block and conclude with Step 8 8 R...

Page 225: ...ber 2005 Figure 13 4 Test points for checking the 9V supply the forward and reverse RF power and the inhibiting of the transmitter DIRC TOP CAN IF TOP CAN VCO TOP CAN UHF ONLY D TX INH TEST POINT TX I...

Page 226: ...check for inhibiting of transmitter Task 8 check temperature sensor Task 9 power and current are skewed Task 10 repair output matching circuitry Task 11 power and current are low The measurement poin...

Page 227: ...50 TEST LEAD TO TEST SET W 50 TEST LEAD TO TEST SET W D TX INH TEST POINT D TX INH TEST POINT RF CON NECTOR RECEIVER LPF DIREC TIONAL COUPLER PAs BUFFER AMPLIFIER BUFFER AMPLIFIER POWER CONTROL PIN SW...

Page 228: ...in millivolts corresponding to the power level and should be as shown in Table 13 3 6 Confirm the above result by checking the level at the REV PWR test point see Figure 13 4 using an oscilloscope If...

Page 229: ...ired values for the different frequency bands are given in Table 13 2 7 Repeat Step 3 to Step 5 8 Program the radio with the lowest frequency in the radio s frequency band Enter the CCTM command 101 x...

Page 230: ...l at the TX INH test point see Figure 13 4 The signal should be 3 If the signal is inactive as required go to Step 4 If it is active about 1 1V the transmitter is being inhibited go to Step 5 4 Enter...

Page 231: ...the cause 1 Enter the CCTM command 47 to check the temperature reading 2 Of the two numbers returned the first is the temperature in degrees celsius and should be about 25 C If it is go to Task 12 in...

Page 232: ...25W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 13 6 PA circuitry under the PAF TOP can and part of the directional coupler under the DIRC TOP can B1 band Mounting point for tes...

Page 233: ...Finding 25W 235 Tait Electronics Limited October 2005 Figure 13 7 PA circuitry under the PAF TOP can and part of the directional coupler under the DIRC TOP can H5 and H6 bands Mounting point for test...

Page 234: ...ead to the test set 6 Program the radio with the highest frequency in the radio s frequency band Enter the CCTM command 101 x x 0 where x is the frequency in hertz 7 Enter the CCTM command 33 to place...

Page 235: ...radio in transmit mode 5 Note the RF output power measured by the test set and note the current reading on the DC power supply 6 Enter the CCTM command 32 to place the radio in receive mode 7 Program...

Page 236: ...e check with the second PA If it is not enter the CCTM command 32 to place the radio in receive mode and carry out Task 12 and then Task 13 7 For the second PA Q309 enter the CCTM command 332 to check...

Page 237: ...asing If the transmitter is not being inhibited check the biasing of the two PAs and the PA driver First make the following preparations 1 Set the current limit on the DC power supply to 2A 2 Enter th...

Page 238: ...QUENCY SYNTHE SIZER CDC TX DRV BIAS CDC TX FIN BIAS1 CDC TX FIN BIAS2 CDC TX PWR CTL TX FWD PWR TX REV PWR CODEC AND AUDIO CIRCUITRY SIGNAL TYPES RF ANALOG SET PWR TEST POINT SET PWR TEST POINT DRV TE...

Page 239: ...k 12 this will be less than 500mA 3 Enter the CCTM command 331 x where x was recorded in Task 12 4 Check that the voltage changes to 5 Also note the current reading This should increase by an amount a...

Page 240: ...anual Tait Electronics Limited October 2005 Figure 13 9 Test points and components of the shaping filter DIRC TOP CAN IF TOP CAN VCO TOP CAN UHF ONLY SET PWR TEST POINT FWD PWR TEST POINT PWR TEST POI...

Page 241: ...ommand 32 to place the radio in receive mode 3 Remove the PAF TOP can 4 Enter the CCTM command 33 to place the radio in transmit mode 5 Enter the CCTM command 331 x where x was recorded in Task 12 6 C...

Page 242: ...t Electronics Limited October 2005 Figure 13 10 PA circuitry under the PAF TOP can H5 H6 BANDS B1 BAND CICUITRY BETWEEN IC301 AND PAs H5 AND H6 BANDS SIMILAR VIA TO GATE OF Q309 VIA TO GATE OF Q310 VI...

Page 243: ...1 Use the multimeter to measure the voltage at the FIN1 test point see Figure 13 9 The voltage should be 2 Enter the CCTM command 331 x where x was recorded in Task 12 3 Check that the voltage change...

Page 244: ...3 9 The voltage should be 2 Note the current reading on the DC power supply As mentioned in Step 7 of Task 12 the current will be less than 500mA 3 Enter the CCTM command 332 y where y was recorded in...

Page 245: ...er the CCTM command 32 to place the radio in receive mode 3 Remove the PAF TOP can 4 Enter the CCTM command 33 to place the radio in transmit mode 5 Enter the CCTM command 332 y where y was recorded i...

Page 246: ...1 Use the multimeter to measure the voltage at the FIN2 test point see Figure 13 9 The voltage should be 2 Enter the CCTM command 332 y where y was recorded in Task 12 3 Check that the voltage change...

Page 247: ...clamp current 3 Note the current reading on the DC power supply 4 Compare the above current readings The current should increase by an amount approximately equal to the offset given in Table 13 6 If i...

Page 248: ...Task 21 3 If the PAD TOP can has already been removed go to Step 7 If it has not go to Step 4 4 Enter the CCTM command 32 to place the radio in receive mode 5 Remove the PAD TOP can 6 Enter the CCTM...

Page 249: ...ransmitter Fault Finding 25W 251 Tait Electronics Limited October 2005 Figure 13 11 PA driver circuitry under the PAD TOP can B1 band Components C310 R324 R327 Gate of Q306 Components C310 R324 R327 G...

Page 250: ...urrent reading on the DC power supply 3 Enter the CCTM command 114 0 to switch off the power 4 Note the current reading on the DC power supply 5 Compare the above current readings The current should d...

Page 251: ...TB7100 Service Manual Transmitter Fault Finding 25W 253 Tait Electronics Limited October 2005 Figure 13 12 Circuitry under the DIRC TOP can B1 band H5 H6 bands...

Page 252: ...5 of IC303 or use the FWD PWR test point see Figure 13 9 Note that the probe impedance might affect the measurement 7 Enter the CCTM command 32 to place the radio in receive mode 8 The voltage measure...

Page 253: ...ol circuit and the PA driver will be located as well as any fault with the PA driver 1 Check for short circuits at the gate of the PA driver Q306 Check R333 R336 see Figure 13 9 C310 R324 and R327 see...

Page 254: ...256 Transmitter Fault Finding 25W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 13 13 Components of concern on the bottom side of the main board B1 band H5 H6 bands...

Page 255: ...e 13 9 if none of the other components is faulty Confirm the removal of the fault and go to Final Tasks on page 123 If the repair failed replace the main board assembly and go to Final Tasks on page 1...

Page 256: ...30 directional coupler Task 31 and Task 32 PIN switch Task 33 LPF The initial signal path includes the exciter and PA driver The directional coupler PIN switch and LPF make up the final signal path Th...

Page 257: ...where x defines the level To set the frequency enter the CCTM command 101 x x 0 where x is the frequency in hertz 3 Enter the CCTM command 33 to place the radio in transmit mode 4 Use an RFP5401A RF...

Page 258: ...cs Limited October 2005 Figure 13 15 PA driver circuitry under the PAD TOP can B1 band Exciter output at C301 H5 H6 bands Driver output Synthesizer output at C300 Buffer output at C313 Exciter output...

Page 259: ...155 174 0 3 0 1 0 2 0 1 0 3 0 1 0 4 0 1 0 4 0 1 0 3 0 1 2 5 0 5 2 5 0 5 2 5 0 5 8 2 0 5 5 5 0 5 7 7 0 5 Table 13 9 RF voltages along the initial RF signal path of the UHF radio H5 and H6 bands Power...

Page 260: ...Repair any fault revealed by the above checks Replace Q300 see Figure 13 15 if none of the other components is faulty 10 Confirm the removal of the fault and go to Final Tasks on page 123 If the repa...

Page 261: ...y do not go to Task 12 in Biasing of PA Driver and PAs on page 239 6 Repair the fault Confirm the removal of the fault and go to Final Tasks on page 123 If the repair failed replace the main board ass...

Page 262: ...ing 25W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 13 16 Components of the interstage matching circuitry between the PA driver Q306 and the PAs Q309 and Q310 B1 band PAF TOP ca...

Page 263: ...der the outer sheath to the test pad shown in Figure 13 24 and solder the central wire to the other terminal of the test capacitor 5 Connect the test lead to the test set 6 Enter the CCTM command 326...

Page 264: ...t set enter the CCTM command 326 5 to set the transmitter power level to the maximum 6 Enter the CCTM command 101 x x 0 where x is the lowest frequency in hertz for maximum power as given in Table 13...

Page 265: ...central wire to the other terminal of the test capacitor 5 Connect the test lead to the test set 6 Enter the CCTM command 326 5 to set the transmitter power level to the maximum 7 Enter the CCTM comm...

Page 266: ...25W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 13 17 Circuitry under the PIN TOP can and points for attaching the test lead and test capacitor B1 band H5 H6 bands Mounting poin...

Page 267: ...e CCTM command 326 5 to set the transmitter power level to the maximum 4 Enter the CCTM command 101 x x 0 where x is the lowest frequency in hertz for maximum power as given in Table 13 8 B1 band or T...

Page 268: ...inding 25W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 13 18 Components of concern on the bottom side of the main board B1 BAND COPPER PLATE VCO BOT CAN NB BOT CAN COPPER PLATE...

Page 269: ...TB7100 Service Manual Transmitter Fault Finding 25W 271 Tait Electronics Limited October 2005 Figure 13 19 Circuitry under the LPF TOP can top side B1 band H5 H6 bands...

Page 270: ...r power level to the maximum 5 Enter the CCTM command 101 x x 0 where x is the lowest frequency in hertz for maximum power as given in Table 13 8 B1 band or Table 13 9 H5 H6 6 Enter the CCTM command 3...

Page 271: ...Controlled Test Mode CCTM on page 91 Table 14 1 CCTM commands required for the diagnosis of faults in the transmitter Command Description 32 33 47 101 x y 0 114 x 304 304 x 318 319 326 x 331 331 x 332...

Page 272: ...ve cans shielding the bulk of the transmitter circuitry PAD TOP PAF TOP DIRC TOP PIN TOP LPF TOP To remove any can first remove the main board assembly from the chassis In the case of the PAD TOP and...

Page 273: ...mbly will be connected to the RF communications test set as shown in Figure 6 2 on page 83 But for those tests where this connection is not necessary a 50 load may be used instead Do not operate the t...

Page 274: ...or in PSU module 9V0 TX The measurement and test points for diagnosing faults in the power supplies are summarized in Figure 14 1 Figure 14 1 Measurement and test points for diagnosing faults involvin...

Page 275: ...et the radio to maximum power 5 Attempt to place the radio in transmit mode Enter the CCTM command 33 6 If the radio enters the transmit mode continue with Step 7 If instead a C03 error is displayed i...

Page 276: ...tter Fault Finding 50W 40W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 14 2 Point for measuring the power supply to the PAs B1 band Q310 B1 BAND Q309 L310 PAF TOP MEASUREMENT PO...

Page 277: ...nual Transmitter Fault Finding 50W 40W 279 Tait Electronics Limited October 2005 Figure 14 3 Point for measuring the power supply to the PAs H5 and H7 bands PAF TOP H5 H7 BANDS Q310 Q309 L310 MEASUREM...

Page 278: ...vice Manual Tait Electronics Limited October 2005 Figure 14 4 Point for measuring the power supply to the PA driver B1 band B1 BAND L306 Q308 R339 R350 Q306 PADTOP MEASUREMENT POINT ON L306 POINT 1 ON...

Page 279: ...W 281 Tait Electronics Limited October 2005 Figure 14 5 Point for measuring the power supply to the PA driver H5 and H7 bands R339 Q308 H5 H7 BANDS L306 R350 Q306 PADTOP MEASUREMENT POINT ON L306 POIN...

Page 280: ...be 4 If the voltage measured in Step 3 is correct go to Step 5 If it is not go to Task 3 and check the 9V power supply 5 Measure the voltage at the point 2 on R350 shown in Figure 14 4 B1 band or Figu...

Page 281: ...CCTM command 33 to place the radio in transmit mode 3 Measure the supply voltage between the 9V0 TX test point and the GND test point see Figure 14 6 4 Enter the CCTM command 32 to place the radio in...

Page 282: ...supply the forward and reverse RF power and the inhibiting of the transmitter B1 BAND H5 H7 BANDS IF TOP CAN VCO TOP CAN IF TOP CAN DIRC TOP CAN DIRC TOP CAN D TX INH TEST POINT TX INH TEST POINT TX...

Page 283: ...k 7 check for inhibiting of transmitter Task 8 check temperature sensor Task 9 power and current are skewed Task 10 repair output matching circuitry Task 11 power and current are low The measurement p...

Page 284: ...T 50 TEST LEAD TO TEST SET W 50 TEST LEAD TO TEST SET W D TX INH TEST POINT D TX INH TEST POINT RF CON NECTOR RECEIVER LPF DIREC TIONAL COUPLER PAs BUFFER AMPLIFIER BUFFER AMPLIFIER POWER CONTROL PIN...

Page 285: ...ge in millivolts corresponding to the power level and should be as shown in Table 14 3 6 Confirm the above result by checking the level at the REV PWR test point see Figure 14 6 using an oscilloscope...

Page 286: ...values for the different frequency bands are given in Table 14 2 7 Repeat Step 3 to Step 5 8 Program the radio with the lowest frequency in the radio s frequency band Enter the CCTM command 101 x x 0...

Page 287: ...d current values measured in Task 5 are correct it is likely that the power remains unchanged regardless of the power setting 1 Enter the following CCTM commands in turn and measure the RF output powe...

Page 288: ...ignal at the D TX INH test point see Figure 14 18 on page 316 B1 band or Figure 14 6 H5 H7 bands The signal should be 6 If the signal is inactive as required go to Step 8 If it is active about 3 2V th...

Page 289: ...d the first is the temperature in degrees celsius and should be about 25 C If it is go to Task 12 in Biasing of PA Driver and PAs on page 297 If it is not go to Step 3 3 If not already done remove the...

Page 290: ...ual Tait Electronics Limited October 2005 Figure 14 8 PA circuitry under the PAF TOP can and part of the directional coupler under the DIRC TOP can B1 band B1 BAND C348 C349 C350 D301 Q309 Q310 TEST P...

Page 291: ...it Electronics Limited October 2005 Figure 14 9 PA circuitry under the PAF TOP can and part of the directional coupler under the DIRC TOP can H5 and H7 bands H5 H7 BANDS C348 C349 C350 D301 Q310 Q309...

Page 292: ...to the test set 6 Program the radio with the highest frequency in the radio s frequency band Enter the CCTM command 101 x x 0 where x is the frequency in hertz 7 Enter the CCTM command 33 to place th...

Page 293: ...o in transmit mode 5 Note the RF output power measured by the test set and note the current reading on the DC power supply 6 Enter the CCTM command 32 to place the radio in receive mode 7 Program the...

Page 294: ...the check with the second PA If it is not enter the CCTM command 32 to place the radio in receive mode and carry out Task 12 and then Task 13 7 For the second PA Q309 enter the CCTM command 332 to che...

Page 295: ...Biasing If the transmitter is not being inhibited check the biasing of the two PAs and the PA driver First make the following preparations 1 Set the current limit on the DC power supply to 3A 2 Enter...

Page 296: ...SYNTHE SIZER CDC TX DRV BIAS CDC TX FIN BIAS1 CDC TX FIN BIAS2 CDC TX PWR CTL TX FWD PWR TX REV PWR CODEC AND AUDIO CIRCUITRY SIGNAL TYPES RF ANALOG SET PWR TEST POINT SET PWR TEST POINT DRV TEST POIN...

Page 297: ...p 7 of Task 12 this will be less than 500mA 3 Enter the CCTM command 331 x where x was recorded in Task 12 4 Check that the voltage changes to 5 Also note the current reading This should increase by a...

Page 298: ...October 2005 Figure 14 11 Test points and components of the shaping filter B1 band R340 R334 R347 R342 C324 C322 R336 R333 IC303 IC301 B1 BAND DIRC TOP CAN DRV TEST POINT REV PWR TEST POINT FWD PWR TE...

Page 299: ...05 Figure 14 12 Test points and components of the shaping filter H5 and H7 bands IC301 R334 IC303 R333 R336 R347 R342 C324 C322 H5 H7 BANDS DIRC TOP CAN FWD PWR TEST POINT REV PWR TEST POINT IF TOP CA...

Page 300: ...lace the radio in receive mode 3 Remove the PAF TOP can 4 Enter the CCTM command 33 to place the radio in transmit mode 5 Enter the CCTM command 331 x where x was recorded in Task 12 6 Check that the...

Page 301: ...ing 50W 40W 303 Tait Electronics Limited October 2005 Figure 14 13 PA circuitry under the PAF TOP can B1 band B1 BAND Q310 Q309 CIRCUITRY BETWEEN IC301 AND PAs VIA TO GATE OF Q310 VIA TO GATE OF Q309...

Page 302: ...ce Manual Tait Electronics Limited October 2005 Figure 14 14 PA circuitry under the PAF TOP can H5 and H7 bands H5 H7 BANDS Q310 Q309 CIRCUITRY BETWEEN IC301 AND PAs VIA TO GATE OF Q310 VIA TO GATE OF...

Page 303: ...meter to measure the voltage at the FIN1 test point see Figure 14 11 and Figure 14 12 The voltage should be 2 Enter the CCTM command 331 x where x was recorded in Task 12 3 Check that the voltage chan...

Page 304: ...d Figure 14 12 The voltage should be 2 Note the current reading on the DC power supply As mentioned in Step 7 of Task 12 the current will be less than 500mA 3 Enter the CCTM command 332 y where y was...

Page 305: ...mand 32 to place the radio in receive mode 3 Remove the PAF TOP can 4 Enter the CCTM command 33 to place the radio in transmit mode 5 Enter the CCTM command 332 y where y was recorded in Task 12 6 Che...

Page 306: ...meter to measure the voltage at the FIN2 test point see Figure 14 11 and Figure 14 12 The voltage should be 2 Enter the CCTM command 332 y where y was recorded in Task 12 3 Check that the voltage chan...

Page 307: ...urrent 3 Note the current reading on the DC power supply 4 Compare the above current readings The current should increase by an amount approximately equal to the offset given in Table 14 6 If it does...

Page 308: ...to Task 21 3 If the PAD TOP can has already been removed go to Step 7 If it has not go to Step 4 4 Enter the CCTM command 32 to place the radio in receive mode 5 Remove the PAD TOP can 6 Enter the CCT...

Page 309: ...Transmitter Fault Finding 50W 40W 311 Tait Electronics Limited October 2005 Figure 14 15 PA driver circuitry under the PAD TOP can B1 band PADTOP Q3504 B1 BAND R327 C310 R324 Q306 COMPONENTS C310 R324...

Page 310: ...ding 50W 40W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 14 16 PA driver circuitry under the PAD TOP can H5 and H7 bands PADTOP H5 H7 BANDS Q306 R324 C310 R327 GATE OF Q306 COMP...

Page 311: ...reading on the DC power supply 3 Enter the CCTM command 114 0 to switch off the power 4 Note the current reading on the DC power supply 5 Compare the above current readings The current should decrease...

Page 312: ...314 Transmitter Fault Finding 50W 40W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 14 17 Circuitry under the DIRC TOP can B1 band H5 H7 bands...

Page 313: ...might affect these measurements 6 Enter the CCTM command 32 to place the radio in receive mode 7 The voltages measured in Step 5 should be as given in Table 14 7 If they are go to Step 10 If the FWD...

Page 314: ...located as well as any fault with the PA driver 1 Check for short circuits at the gate of the PA driver Q306 Check R333 R336 see Figure 14 11 and Figure 14 12 C310 R324 and R327 see Figure 14 15 and F...

Page 315: ...Transmitter Fault Finding 50W 40W 317 Tait Electronics Limited October 2005 Figure 14 19 Components of concern on the bottom side of the main board H5 and H7 bands H5 H7 BANDS C319 R341 R340 R396 COP...

Page 316: ...e the voltage at pin 10 of IC303 in the power control circuit The voltage should be 4 If the voltage is correct go to Step 5 If it is not go to Task 25 5 Enter the CCTM command 32 to place the radio i...

Page 317: ...f the voltage measured in Step 1 is correct go to Step 4 If it is not go to Step 5 4 Check the components R334 see Figure 14 11 and Figure 14 12 and C319 see Figure 14 18 and Figure 14 19 and go to St...

Page 318: ...oupler Task 33 and Task 34 PIN switch Task 35 LPF The initial signal path includes the exciter and PA driver The directional coupler PIN switch and LPF make up the final signal path The measurement po...

Page 319: ...the level To set the frequency enter the CCTM command 101 x x 0 where x is the frequency in hertz 3 Enter the CCTM command 33 to place the radio in transmit mode 4 Use an RFP5401A RF probe or the equi...

Page 320: ...ver circuitry under the PAD TOP can B1 band PADTOP Q306 C3500 C3505 C3509 C307 Q3501 Q3504 Q3502 Q3505 R3525 OUTPUT OF PA DRIVER OUTPUT OF STAGE 3 OF EXCITER AT C307 OUTPUT OF STAGE 1 OF EXCITER AT C3...

Page 321: ...ry under the PAD TOP can H5 and H7 bands PADTOP Q3504 C317 C389 Q306 C3500 C3505 C3509 C307 Q3501 Q3502 Q3505 H5 H7 BANDS OUTPUT OF PA DRIVER OUTPUT OF STAGE 3 OF EXCITER AT C307 R3525 JUNCTION OF R35...

Page 322: ...5 0 0 5 15 6 0 5 70 136 155 174 0 3 0 1 0 2 0 1 0 3 0 1 0 6 0 2 0 6 0 2 0 7 0 2 2 7 0 5 2 2 0 5 1 7 0 5 4 0 0 5 3 7 0 5 4 0 0 5 24 5 0 5 29 0 0 5 22 0 0 5 Table 14 9 RF voltages along the initial RF s...

Page 323: ...5 7 0 5 3 4 0 5 2 4 0 5 2 5 0 5 2 0 0 5 0 9 0 5 15 450 485 520 0 2 0 1 0 2 0 1 0 2 0 1 1 1 0 2 1 0 0 2 1 2 0 2 2 2 0 5 1 9 0 5 0 9 0 5 5 7 0 5 3 4 0 5 2 4 0 5 3 1 0 5 2 4 0 5 1 1 0 5 20 450 485 520 0...

Page 324: ...Measure the RF voltage after C3505 see Figure 14 21 and Figure 14 22 Use an RFP5401A RF probe or the equivalent The required voltage should be as given in Table 14 8 B1 band Table 14 9 H5 or Table 14...

Page 325: ...lent The required voltage should be as given in Table 14 8 B1 band Table 14 9 H5 or Table 14 10 H7 2 If the voltage is correct go to Task 30 If it is not go to Step 3 3 Enter the CCTM command 32 to pl...

Page 326: ...ransmit mode measure the RF voltage at the junction of R3525 and C3512 see Figure 14 21 and Figure 14 22 The voltage should be 4 Enter the CCTM command 32 to place the radio in receive mode 5 If the v...

Page 327: ...If they do not go to Task 12 in Biasing of PA Driver and PAs on page 297 6 Repair the fault Confirm the removal of the fault and go to Final Tasks on page 123 If the repair failed replace the main bo...

Page 328: ...40W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 14 23 Components of the interstage matching circuitry between the PA driver Q306 and the PAs Q309 and Q310 B1 band B1 BAND Q310...

Page 329: ...Finding 50W 40W 331 Tait Electronics Limited October 2005 Figure 14 24 Components of the interstage matching circuitry between the PA driver Q306 and the PAs Q309 and Q310 H5 and H7 bands H5 H7 BANDS...

Page 330: ...st pad shown in Figure 14 25 and solder the central wire to the other terminal of the test capacitor 5 Connect the test lead to the test set 6 Enter the CCTM command 326 5 to set the transmitter power...

Page 331: ...Finding 50W 40W 333 Tait Electronics Limited October 2005 Figure 14 25 Circuitry under the DIRC TOP can and the points for attaching the test lead and test capacitor B1 band H5 H7 bands Mounting poin...

Page 332: ...M command 326 5 to set the transmitter power level to the maximum 6 Enter the CCTM command 101 x x 0 where x is the lowest frequency in hertz for maximum power as given in Table 14 8 B1 band Table 14...

Page 333: ...er terminal of the test capacitor 5 Connect the test lead to the test set 6 Enter the CCTM command 326 5 to set the transmitter power level to the maximum 7 Enter the CCTM command 101 x x 0 where x is...

Page 334: ...al Tait Electronics Limited October 2005 Figure 14 26 Circuitry under the PIN TOP can and points for attaching the test lead and test capacitor H5 H7 BANDS B1 BAND C361 C362 C363 D307 C361 C362 C363 D...

Page 335: ...nected to the test set enter the CCTM command 326 5 to set the transmitter power level to the maximum 5 Enter the CCTM command 101 x x 0 where x is the lowest frequency in hertz for maximum power as g...

Page 336: ...Fault Finding 50W 40W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 14 27 Components of concern on the bottom side of the main board B1 band B1 BAND R389 R390 NB BOT CAN COPPER PL...

Page 337: ...al Transmitter Fault Finding 50W 40W 339 Tait Electronics Limited October 2005 Figure 14 28 Components of concern on the bottom side of the main board H5 and H7 bands H5 H7 BANDS R3000 R389 R390 COPPE...

Page 338: ...340 Transmitter Fault Finding 50W 40W TB7100 Service Manual Tait Electronics Limited October 2005 Figure 14 29 Circuitry under the LPF TOP can B1 BAND H5 H7 BANDS...

Page 339: ...et the transmitter power level to the maximum 6 Enter the CCTM command 101 x x 0 where x is the lowest frequency in hertz for maximum power as given in Table 14 8 B1 band Table 14 9 H5 or Table 14 10...

Page 340: ...342 Transmitter Fault Finding 50W 40W TB7100 Service Manual Tait Electronics Limited October 2005...

Page 341: ...e correct amount of RF power In the fifth case the transmitter will be operating normally Fault Diagnosis Procedures The procedures for diagnosing the above faults are given below in the following sec...

Page 342: ...emove the main board assembly from the chassis 2 Remove the CDC BOT can 3 Measure the voltage 9V0 at pin 4 of IC201 see Figure 15 1 4 If the voltage is correct go to Task 2 If it is not go to Step 5 5...

Page 343: ...rvice Manual CODEC and Audio Fault Finding 345 Tait Electronics Limited October 2005 Figure 15 1 Power supply circuitry for the CODEC and audio circuitry under the CDC BOT can LO2 BOT CAN CAN FOR DIGI...

Page 344: ...IC604 is suspect see Figure 15 1 Check the regulator as described in Task 3 of Power Supply Fault Finding on page 132 4 Proceed to the section relevant to the fault exhibited Faulty Speaker Audio dis...

Page 345: ...unmute criteria are satisfied but there is either no speaker audio or the speaker audio is distorted There are four tasks Task 4 check audio power amplifier Task 5 check speaker outputs Task 6 check I...

Page 346: ...Task 7 5 Vary the volume control This should cause the signal level at the TP200 test point see Figure 15 2 to vary If it does go to Step 6 If it does not go to Task 6 6 Check the voltage at pin 11 of...

Page 347: ...assembly and go to Final Tasks on page 123 5 With the volume at maximum check each speaker output at pins 3 and 8 of IC202 see Figure 15 2 6 If the speaker outputs are correct the fault is unknown it...

Page 348: ...nd Audio Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005 Figure 15 3 Circuitry under the CDC TOP can and adjacent interface circuitry Junction of R234 and R235 Junction of R7...

Page 349: ...sks on page 123 If the repair failed or the fault could not be found replace the main board assembly and go to Final Tasks on page 123 5 Remove the CDC TOP can 6 Check the voltage at the junction of R...

Page 350: ...EC and Audio Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005 Figure 15 4 Circuitry under the CDC BOT can LO2 BOT CAN CAN FOR DIGITAL BOARD JUNCTION OF R218 AND IC204 CDC AUD...

Page 351: ...rect go to Step 4 If it is not either CODEC 1 IC204 or the digital board is faulty replace the main board assembly and go to Final Tasks on page 123 4 Check for continuity between the TP200 test point...

Page 352: ...ere is no signal at pin 13 AUD TAP OUT of the connector The fault diagnosis procedure comprises two tasks Task 8 check signal from CODEC Task 9 check LPF and buffer amplifier in CODEC circuitry These...

Page 353: ...s connector SK102 see Figure 15 5 alternatively the measurement point for CDC AUD TAP OUT shown in Figure 15 4 The signal should be 7 If the above signal is correct go to Step 8 If it is not go to Tas...

Page 354: ...356 CODEC and Audio Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005 Figure 15 6 Circuitry in the vicinity of the auxiliary connector bottom side AUXILIARY CONNECTOR SK101...

Page 355: ...n IC201 pins 1 to 3 see Figure 15 7 Repair any fault and conclude with Step 9 6 Check the voltage at pin 7 of IC201 see Figure 15 7 7 If the voltage is correct go to Step 8 If it is not check the buff...

Page 356: ...358 CODEC and Audio Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005 Figure 15 7 Circuitry under the CDC BOT can LO2 BOT CAN CAN FOR DIGITAL BOARD JUNCTION OF R224 AND IC204...

Page 357: ...With no RF signal applied check the voltage at pin 14 of IC201 see Figure 15 7 3 If the above voltage is correct go to Task 11 If it is not go to Step 4 4 Check the voltage at pin 12 of IC201 see Figu...

Page 358: ...nd Audio Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005 Figure 15 8 Circuitry in the vicinity of the CDC TOP can B1 band H5 H6 bands Junction of C708 and C732 Junction of C7...

Page 359: ...se the programming application to find the frequency selected for channel 1 2 Apply a strong on channel signal 3 Check that a sine wave is present at the QN test point there is access through a hole i...

Page 360: ...he part of the circuitry that is faulty 1 Apply a 1kHz audio signal of 20 mVpp at the microphone input 2 Enter the CCTM command 33 to place the radio in transmit mode The frequency is that of channel...

Page 361: ...TB7100 Service Manual CODEC and Audio Fault Finding 363 Tait Electronics Limited October 2005 Figure 15 9 Circuitry in under the CDC BOT can LO2 BOT CAN CAN FOR DIGITAL BOARD...

Page 362: ...oard assembly and go to Final Tasks on page 123 Task 14 Check Bias Network If the signal at the TP503 test point is incorrect but the other checks in the above tasks reveal no fault check the bias net...

Page 363: ...100 Service Manual CODEC and Audio Fault Finding 365 Tait Electronics Limited October 2005 Figure 15 10 Circuitry under the CDC TOP can ITF AUD TAP IN JUNCTION OF R237 AND R241 JUNCTION OF R229 AND R2...

Page 364: ...mand 32 to place the radio in receive mode 4 If the modulation is correct go to Step 5 If it is not go to Task 12 of Faulty Modulation on page 362 5 Apply a 1kHz AC coupled signal of 0 7Vpp at pin 7 A...

Page 365: ...eplace IC205 see Figure 15 10 5 Confirm the removal of the fault and go to Final Tasks on page 123 If the repair failed replace the main board assembly and go to Final Tasks on page 123 6 Remove R241...

Page 366: ...368 CODEC and Audio Fault Finding TB7100 Service Manual Tait Electronics Limited October 2005...

Page 367: ...ower cable 4 way to M3 5 spade 50W 40W version Transmitter power cable 4 way to M3 5 spade 25W version 1 219 02975 xx 219 02976 xx Figure 7 9 Receiver power cable 4 way to M3 5 spade 50W 40W version R...

Page 368: ...ure 7 7 Screw M3x10 through regulator on SI board 1 345 00040 xx Figure 7 7 Fan 2 219 02993 xx Figure 7 8 Fan duct 1 319 01269 xx Figure 7 8 Screw M3x25 fans 4 345 00040 xx Figure 7 8 Cable tie 5 369...

Page 369: ...FY REVERSE COMPILE OR REVERSE ASSEMBLE ANY SOFTWARE OR FIRMWARE IN WHOLE OR PART Important Notice THE SOFTWARE OR FIRMWARE MAY CONTAIN OPEN SOURCE SOFTWARE COMPONENTS OPEN SOURCE COMPONENTS OPEN SOURC...

Page 370: ...SOLE AND TOTAL LIABILITY FOR ANY SUCH CLAIM SHALL BE LIMITED AT THE OPTION OF TAIT TO THE REPAIR OR REPLACEMENT OF THE SOFTWARE OR FIRMWARE OR THE REFUND OF THE PURCHASE PRICE OF THE SOFTWARE OR FIRM...

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