Panasonic KX-T7456 - Digital 24 Button Speakerphone Display Specifications Download Page 17 | Manualshive

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6. BLOCK DIAGRAM

7. CIRCUIT OPERATIONS

7.1. KEY INPUT CONTROL CIRCUIT

1) Circuit Operation

Sequential input information (negative logic) from the DSHS proprietary telephone is executed
by dynamic scanning.
The ports RR70 to RR73, RR80 to RR83 of IC6 are brought to low status consecutively.
If a key is pressed, the key-in information input is executed by ports R91 to R93, RB1, RB11,
RB21, RB0, RD1.

7.2. LCD CONTROL CIRCUIT

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Summary of Contents for KX-T7456 - Digital 24 Button Speakerphone Display

Page 1: ...ORDER NO KMS0104564C1 F5 DIGITAL PROPRIETARY TELEPHONE KX T7456 KX T7456B White Version Black Version for U S A SPECIFICATIONS 1 ...

Page 2: ...uthorized copying and distribution is a violation of law 1 CAUTION Note When you note the serial number write down all 11 digitals The serial number may be found on the bottom of the unit 2 FOR SERVICE TECHNICIANS 1 Note the following items when exchanging the LEDs Ref No 2 ...

Page 3: ...t the LED for more than 2 seconds 4 Do not move the LED after soldering 2 This unit employs the switch which is influenced by the light for the hook switch When you open the cabinet to repair the unit in the bright light the hook switch might work improperly Therefore take care not to shine the hook switch directly or use the jig as shown below 3 LOCATION OF CONTROLS 3 ...

Page 4: ...4 DISASSEMBLY INSTRUCTIONS 4 1 HOW TO REMOVE THE LOWER CABINET Procedure 1 4 ...

Page 5: ... 1 Remove the 4 screws A 2 Remove the lower cabinet 4 2 HOW TO REMOVE THE HOOK BUTTON Procedure 1 2 1 Remove the hook button 4 3 HOW TO REMOVE THE SWITCH AND MAIN BOARDS Procedure 1 2 3 5 ...

Page 6: ... the switch board connector 3 Remove the switch board 4 Pull out the flat cable See Fig 1 5 Remove the 2 screws B 6 Pull out the speaker and microphone connectors 7 Remove the main board 4 4 HOW TO REMOVE THE LCD BOARD Procedure 1 4 6 ...

Page 7: ... 1 Pull out the flat cable See Fig 1 2 Remove the LCD block See Fig 2 3 Remove the 2 screws A 4 Remove the lower cabinet 5 Remove the LCD board 7 ...

Page 8: ...5 IC DATA 5 1 IC1 8 ...

Page 9: ... Stream 0 SR1 20 input 12 38k TTL high PT5D01U 0 1 Serial Receive Data Stream 1 SX 21 output CMOS 4 0mA high PC5O02 0 1 Serial Transmit Data Stream CK2M 18 output CMOS 4 0mA high PC5O02 2 1 Serial Stream Clock EP0 13 output CMOS 2 0mA high PC5O01 0 01 External Channel Pulse EP1 14 output CMOS 2 0mA high PC5O01 0 01 External Channel Pulse EP2 15 output CMOS 2 0mA high PC5O01 0 01 External Channel P...

Page 10: ...30 input 12 38k CMOS high PC5D01U 0 01 Input Port 3 OP0 23 output CMOS 4 0mA high PC5O02 0 01 Output Port 0 OP1 24 output CMOS 4 0mA high PC5O02 0 01 Output Port 1 OP2 25 output CMOS 4 0mA high PC5O02 0 01 Output Port 2 OP3 26 output CMOS 4 0mA high PC5O02 0 01 Output Port 3 CK2K 22 output CMOS 4 0mA high PC5O02 0 20 2kHz Clock Output 25 CK16M 36 output CMOS 2 0mA high PC5O01 16 4 Master Clock Out...

Page 11: ...11 ...

Page 12: ...terminal SPO terminal is biased to Vdd 2 voltage Connect the capacitor of 0 1 F in series between the speaker amplifier input terminal and this terminal AG2 9 Power supply etc Ground terminal of the analog circuit P S 10 CMOS inout Micro computer interface Mode selection terminal of microcomputer interface Inputting 0 selects the serial mode and 1 selects the parallel mode RESET 11 System reset te...

Page 13: ...his output DG2 28 Power supply etc Ground terminal of digital circuit OSCI 29 Clock Input terminal of oscillation circuit Connect the oscillator and resistor berween this terminal pin 30 OSCO moreover connect the capacitor between terminal and digital ground to make the oscillation circuit OSCO 30 Output terminal of oscillation circuit Connect the oscillator and resistor berween this terminal pin ...

Page 14: ...t AP1HO 54 Analog output Output terminal of microphone amplofier H1 Connect the capacitor of 0 1 F to this terminal to cut AP1HN 55 Analog input Inverting input terminal of microphone amplofier H1 Connect to the handset AP1HP 56 Analog input Analog Non inverting input terminal of microphone amplofier H1 VREFM 57 Power supply etc Reference voltage terminal of microphone amplifier Connect the capaci...

Page 15: ...15 ...

Page 16: ...2 D13 18 19 Input Input terminal which is adressed every 1 bit R00 R43 R60 RA1 20 57 Input output Input output terminal which is adressed every 4 RB0 2 RD0 1 RE0 60 64 1 Input Input terminal which is adressed every 4 bit Interrupt INT2 INT4 19 23 Input Input terminal for external interrupt Stop clear 18 Input Input terminal used for the transfer from stop mode active mode Serial interface 37 Input...

Page 17: ...nformation negative logic from the DSHS proprietary telephone is executed by dynamic scanning The ports RR70 to RR73 RR80 to RR83 of IC6 are brought to low status consecutively If a key is pressed the key in information input is executed by ports R91 to R93 RB1 RB11 RB21 RB0 RD1 7 2 LCD CONTROL CIRCUIT 17 ...

Page 18: ...o 35 40 to 47 and 11 of IC6 LCD contrast adjustment is performed by the circuit composed of Q28 Q29 R109 R108 and R106 The contrast is determined only by the voltage level between V5 and VEE of IC203 IC204 and IC205 Higher potential makes the contrast high 18 ...

Page 19: ...tput ports C0 to C5 column and R0 to R9 of IC1 A fixed pulse T 1 82 msec is output continuously from the SCK1 terminal of IC9 This pulse is counted and the output of IC1 is shifted sequentially from C0 to C5 R0 to R7 of IC1 also output pulses and the lighting of the LED is controlled by the timing of the output ports C0 to C5 19 ...

Page 20: ...7 4 DATA COMMUNICATION CIRCUIT 1 Function 20 ...

Page 21: ...nal from the DSHS and after sending the key input information to the DSHS and receiving data for the LED control etc the DSHS proprietary telephone will return to the DSHS an acknowledge signal 3 Reception The data from the DSHS is received via the H and L lines along the path shown below H L Line T1 IC11 Pin 5 10 IC1 Pin 38 39 IC1 Pin 21 IC2 Pin 22 IC5 Pin 8 4 Transmission The data to the DSHS pr...

Page 22: ...rface consists of following 4 terminals The first PCM data is output from TXD at the positive edge of FSYNC The second data and the followings are output at the positive edge of BCLK After all data of 8 bit are output the last data is kept until the positive edge of next FSYNC The positive edge of BCLK should be within 100ns from the positive edge of FSYNC The PCM data input from RXD is sampled at...

Page 23: ...CIRCUIT 1 Circuit Operation This circuit is used for transmission of a reset pulse to the CPU IC6 at the following times connecting the telephone line jack and circuit operation The timing chart is shown below 23 ...

Page 24: ...The reset signal is negledted 24 ...

Page 25: ...7 6 TONE GENERATION CIRCUIT 1 Function Calling tones Busy tone DTMF signal and Key in tone are generated in IC2 25 ...

Page 26: ... control The sampling cycle is 1ms and provided with the chattering protective circuit whose available pulse width is 1ms or more These are the rotary encoder inputs and sampled 1 kHz 1 msec cycle The built in chattering protective circuit neglects the input pulse of 1 msec or less The high pulse of 2 msec or more is available The availability of the pulse with the width of 1 2 msec is not ensured...

Page 27: ... of the photo transistor The detection signal is determined by the microcomputer of IC6 7 9 HANDSET CIRCUIT 1 Transmission signal path The analog input signal from the handset microphone is input to the communication LSI through the IC2 built in analog amplifier In this LSI the network control based on A D conversion and the handset software and the gain control based on the down load data from th...

Page 28: ...rt of IC2 The analog switch of IC12 interrupts the input signal Also the OHCA voice signal from the speakerphone IC1 of IC4 is output from the SP phone amplifier IC3 2 Reception siganl path The voice serial data transmitted from PBX is sent to IC2 by the serial transmission Then the signal is output from the handset speakerphone after performing the network control gain control and A D conversion ...

Page 29: ...8 TROUBLESHOOTING GUIDE 8 1 NO OPERATION 8 2 THE LCD DOES NOT OPERATE 29 ...

Page 30: ...8 3 THE ELECTRONIC VOLUME OF THE SPEAKER PHONE DOES NOT WORK 8 4 THE ELECTRONIC VOLUME OF THE HANDSET DOES NOT WORK 30 ...

Page 31: ...8 5 SPEAKER PHONE TROUBLE 8 6 TONE DIAL TROUBLE 8 7 TROUBLE OF OHCA 31 ...

Page 32: ...8 8 HANDSET TROUBLE 9 TERMINAL GUIDE OF ICS TRANSISTORS AND DIODES 32 ...

Page 33: ... a cutter knife you can easily remove IC s even though large than 100 pin 10 1 PREPARATION SOLDER Sparkle Solder 115A 1 115B 1 or Almit Solder KR 19 KR 19RMA Soldering iron Recommended power consumption is between 30 W to 40 W Temperature of Copper Rod 662 50 F 350 10 C An expert may handle a 60 80 W iron but beginner might damage foil by overheating Flux HI115 Specific gravity 0 863 33 ...

Page 34: ...ou do not fill with solder and directly cut the IC lead with the cutter stress may build up directly in the P C board s pattern If you do not fill with large quantities of solder as in step 1 the P C board pattern may be removed 2 Using a cutter cut the lead at the source Cut the contents with the cutter lightly 5 or 6 times 3 Remove when the solder melts Remove the lead at the same time 34 ...

Page 35: ...DURE 1 Temporary fix FLAT PACKAGE IC by soldering on two marked pins Check the accuracy of the IC setting with the corresponding soldering foil 2 Apply flux for all pins of FLAT PACKAGE IC 3 Solder using the specified solder in the direction of the arrow by sliding the soldering iron 10 4 BRIDGE MODIFICATION PROCEDURE 1 Lightly re solder the bridged portion 2 Remove the remaining solder along pins...

Page 36: ...12 CABINET AND ELECTRICAL PARTS LOCATION 13 ACCESSORIES AND PACKING MATERIALS 36 ...

Page 37: ...S LIST Note 1 The marking RTL indicates that the Retention Time is limited for this item After the discontinuation of this assembly in production the item will continue to be available for a specific period of time The 37 ...

Page 38: ...nd of this period the assembly will no longer be available 2 The S mark indicates service standard parts and may differ from production 3 RESISTORS CAPACITORS Unless otherwise specified All resistors are in ohms K 1000 M 1000k All capacitors are in MICRO FARADS F P F Type Wattage of Resistor 14 1 CABINET AND ELECTRICAL PARTS 38 ...

Page 39: ... BLACK VERSION 18 PSBX1042Z1 BUTTON 4KEY WHITE VERSION 18 PSBX1042Z2 BUTTON 4KEY BLACK VERSION 19 PSBX1052Z3 BUTTON 15KEY WHITE VERSION 19 PSBX1052Z4 BUTTON 15KEY BLACK VERSION 20 PSSX1006Y KEY SWITCH 21 PSBE1001Z1 BUTTON ADJUST WHITE VERSION 21 PSBE1001Z2 BUTTON ADJUST BLACK VERSION 22 PSQA2021Z LABEL NOTE 23 PSGP1025Z1 PANEL LCD WHITE VERSION 23 PSGP1025Z2 PANEL LCD BLACK VERSION 24 PSGG1007Y1 G...

Page 40: ...art Name Description Remarks PCB1 PSWP1T7456UK MAIN BOARD ASS Y RTL ICS IC1 PSVIBU65050D IC IC2 PSVITC5324F2 IC IC3 PQVIMC34119D IC IC4 PQVISC77655V IC S IC5 PSVIMC5480DW IC S IC6 PSVI40612A04 IC IC7 PQVINJU7660M IC S IC8 PQVINJM2904M IC IC9 PSVIBA05FP IC IC10 PSVIBA05FP IC IC11 PQVINJM319V IC IC12 PQVITC4066BF IC SW1 PSVII24015T IC TRANSISTORS Q1 2SA1576Q TRANSISTOR SI Q2 2SA1576Q TRANSISTOR SI Q...

Page 41: ...DIODES D1 PQVDS1ZB60F1 DIODE SI D3 RLS71 DIODE SI D4 RLS71 DIODE SI D5 RLS71 DIODE SI D6 RLS71 DIODE SI D7 RLS71 DIODE SI D8 RLS71 DIODE SI D9 RLS71 DIODE SI D10 RLS71 DIODE SI D11 PSVDUDZ39B DIODE SI D12 RLS71 DIODE SI D13 RLS71 DIODE SI D17 RLS71 DIODE SI LEDS D100 PSVD2SRVGCT LED D101 PSVD2SRVGCT LED D102 PSVD2SRVGCT LED D103 PSVD2SRVGCT LED D104 PSVD2SRVGCT LED D105 PSVD2SRVGCT LED D106 PSVD2S...

Page 42: ...2 PQLQR1LT COIL L5 PQLQR1RM601 COIL L6 PQLQR1RM601 COIL L9 PQLQR1LT COIL CRYSTAL OSCILLATORS X1 PSVCCR1638B7 CRYSTAL OSCILLATOR X2 PSVCCR1228B7 CRYSTAL OSCILLATOR JACKS JK1 PSJJ1T011Z JACK JK2 PSJJ1T012Z JACK TRANSFORMER T1 PSLT9Z4A TRANSFORMER RESISTORS JP3 PQ4R18XJ000 0 JP5 PQ4R18XJ000 0 JP7 PQ4R18XJ000 0 JP16 PQ4R18XJ000 0 J17 ERJ3GEY0R00 0 L7 PQ4R10XJ000 0 L8 PQ4R10XJ000 0 L10 ERJ3GEY0R00 0 L1...

Page 43: ...RJ3GEYJ105 1M R29 ERJ3GEYJ561 560 R30 ERJ3GEYJ151 150 R31 ERJ3GEYJ103 10K R32 ERJ3EKF9102 91K R34 ERJ3GEYJ105 1M R35 ERJ3GEYJ822 8 2K R36 ERJ3GEYJ222 2 2K R37 ERJ3GEYJ225 2 2M R38 ERJ3GEYJ222 2 2K R39 ERJ3GEYJ224 220K R40 ERJ3GEYJ222 2 2K R41 ERJ3GEYJ472 4 7K R42 ERJ3GEYJ103 10K R43 ERJ3GEYJ102 1K R44 ERJ3GEYJ183 18K R45 ERJ3GEYJ103 10K R46 ERJ3GEYJ392 3 9K R47 ERJ3GEYJ683 68K R48 ERJ3GEYJ683 68K ...

Page 44: ... ERJ3GEYJ104 100K R84 ERJ3GEYJ103 10K R85 ERJ3GEYJ103 10K R86 ERJ3GEYJ103 10K R87 ERJ3GEYJ104 100K R88 ERJ3GEYJ333 33K R89 ERJ3GEYJ223 22K R90 ERJ3GEYJ183 18K R91 ERJ3GEYJ103 10K R92 ERJ3GEYJ105 1M R93 ERJ3GEYJ223 22K R94 ERJ3GEYJ223 22K R95 ERJ3GEYJ223 22K R96 ERJ3GEYJ223 22K R97 ERJ3GEYJ223 22K R98 ERJ3GEYJ223 22K R99 ERJ3GEYJ223 22K R100 ERJ3GEYJ223 22K R101 ERJ3GEYJ472 4 7K R102 ERJ3GEYJ472 4 ...

Page 45: ...100K R139 ERJ3GEYJ103 10K R140 ERJ3GEYJ103 10K R141 ERJ3GEYJ271 270 R144 ERJ3GEYJ330 33 R145 ERJ3GEYJ330 33 R146 ERJ3GEYJ330 33 R147 ERJ3GEYJ330 33 R148 ERJ3GEYJ330 33 R149 ERJ3GEYJ330 33 R150 ERJ3GEYJ330 33 R151 ERJ3GEYJ330 33 R152 ERJ3GEYJ330 33 R153 ERJ3GEYJ330 33 R160 ERJ3GEYJ104 100K CAPACITORS C2 ECEV1HA2R2N 2 2 C3 PSCEV1HA010 1 C4 ECUV1H680JCV 68P C5 ECUV1H101JCV 100P C6 ECUV1H680JCV 68P C7...

Page 46: ...H104ZF 0 1 S C47 PQCUV1E104MD 0 1 C48 PQCUV1H153KB 0 015 C49 PQCUV1H473MD 0 047 S C50 PSCEV1HA010 1 C51 PSCEV1HA010 1 C52 PSCEV1EA4R7 4 7 S C53 PQCUV1H683KB 0 068 C55 PSCEV1HA010 1 C56 PSCEV0JA470 47 C57 PQCUV1H682KB 0 0068 C58 PSCEV0JA101 100 S C59 PQCUV1E104MD 0 1 C60 PSCEV0JA101 100 C61 PSCEV0JA102 1000 C62 PQCUV1E104MD 0 1 C63 PSCEV1HA100 10 C64 PQCUV1E104MD 0 1 S C66 ECUV1E102JCV 0 001 C68 PS...

Page 47: ...SS Y RTL ICS IC201 PQVILC7981 IC IC202 PSVIBR665BSD IC IC203 PSVILC7942ND IC IC204 PSVILC7940ND IC IC205 PSVILC7940ND IC IC206 PQVILA5311M IC LED D201 PSVD111R820R LED D202 PSWE1014Z BACKLIGHT CONNECTOR CN201 PSJS36A61Z CONNECTOR 36P SWITCH SW1 PSWE1014Z SWITCH BACKLIGHT RESISTORS R201 PQ4R10XJ100 10 R202 PQ4R10XJ393 39K R203 PQ4R10XJ393 39K R204 PQ4R10XJ102 1K R205 PQ4R10XJ471 470 CAPACITORS C200...

Page 48: ... PSWP3T7431UK SWITCH BOARD ASS Y RTL SWITCH SW301 PSSRCA101Z SWITCH JOG DIAL CONNECTOR CN301 PSJS03Q36Z CONNECTOR 3P 15 PRINTED CIRCUIT BOARD 15 1 MAIN BOARD COMPONENT VIEW 15 2 MAIN BOARD BOTTOM VIEW 16 SCHEMATIC DIAGRAM 17 PRINTED CIRCUIT BOARD H KXT7456MUK KXT7456MBUK 48 ...

Page 49: ...33 37 34 35 36 25 32 ...

Page 50: ... R44 R46 D11 D129 D126 R124 R125 R126 CO6 D128 3 D127 TRANS D104 CO23 D110 CO17 D116 CO11 D122 CO5 PAUSE MW MUTE AUTO FLASH D103 CO22 D109 CO16 D115 CO10 D121 CO4 D125 D124 PROG HOLD REDIAL D101 CO20 D107 CO14 D113 CO8 D119 CO2 CONF D130 D100 CO19 D106 CO13 D112 CO7 D118 CO1 INT D102 CO21 D108 CO15 D114 CO9 D120 CO3 FWD DND SP PHONE 6 9 2 5 8 0 1 4 7 ...

Page 51: ...7 R16 C111 A7 A8 R26 R132 R131 Q12 Q11 R25 R24 R23 A5 Q10 C113 C112 R121 R139 R100 R99 F8 E2 E3 E4 B6 E1 CN2 IC6 33 48 16 1 32 49 R96 R97 F7 17 64 2 1 36 35 R22 R19 R18 R21 R20 Q8 Q3 Q9 Q6 Q18 B1 B4 A3 A4 Q17 Q15 Q14 Q13 Q16 Q5 Q4 L5 R144 R149 C116 R134 R115 L11 64 A6 Q7 L16 L15 L14 R6 C7 C5 R1 C4 X1 L12 R28 32 17 C18 R2 CN5 R113 R160 C17 R3 C8 R7 R4 R5 T1 7 8 6 10 1 5 Q24 B2 A1 A2 SW1 R116 Q32 JP...

Page 52: ...53 53 O51 51 O50 50 O49 49 O48 48 O47 47 O45 45 O44 44 O43 43 O42 42 O41 41 O39 39 O38 38 O37 37 O36 36 O35 35 O33 33 O32 32 O31 31 O30 30 O29 29 O27 27 O26 26 O25 25 O24 24 O23 23 O21 21 O20 20 O19 19 O18 18 O17 17 O15 15 O14 14 O13 13 O12 12 O11 11 O9 9 O8 8 O7 7 O6 6 O5 5 O3 3 O2 2 O1 1 V3 89 V4 88 VDD 91 VDD 90 D13 96 D12 95 D11 94 P S 85 VSS 86 VEE 87 SDI 97 LOAD 98 M 93 CP 100 CDI 99 DISP_OF...

Page 53: ...V1 R160 100K L5 L10 0 L12 33 L13 33 L14 33 L15 33 L16 33 L17 33 R144 33 R150 33 R151 33 R152 33 R153 33 R145 33 R146 33 R147 33 R148 33 R149 33 L4 3 2 4 1 L11 0 L6 R141 270 R136 0 R137 Q32 SW301 2 JOG 2 1 JOG 1 3 GND CN301 2 1 3 J17 0 C66 1000P C65 1000P JP1 JP6 JP2 JP8 JK1 4 H 1 L 3 T 2 R JP7 0 JP3 0 JP5 0 JP4 JP16 0 CN5 1 G 2 R 3 B 4 W INT 1 R 12 R 13 INT 2 IOR IOW R 20 R 21 R 22 R 23 CO24 G R R...

Page 54: ...52 FR3 SW54 FR5 SHIFT MENU3 MENU2 SW56 MENU1 SW55 D201 CN201 IC206 IC203 IC202 R203 R202 R201 C202 C206 C200 C205 C201 C204 C203 R204 R205 D202 1 1 1 80 8 65 40 1 14 15 28 24 64 41 IC205 IC201 IC204 SW1 51 50 81 5 55 35 54 36 6 31 50 81 100 51 80 30 1 23 24 31 100 80 30 1 4 8 5 2 35 36 ...

Page 55: ...SW301 CN301 1 2 3 ...

Page 56: ...3AP 2AP LED DRIVING Q3 Q12 Q13 Q18 LED D100 D117 D130 5V RESET HOOK SW x2 12 288 MHz x1 5V Main p c board DATA COMMUNI CATION IC11 Q1 Q2 DC DC CONVERTER IC9 T1 POWER REGULATOR D1 IC10 IC7 5V 5V 16 384 MHz RX 1AP TX RX TEL JACK JK1 PBX TX INT RD WT A0 A1 D0 D3 INT RD WT ALE D5 D7 RR RD RB RR RD RB IC2 TEL Communication LSI CODEC D A A D SP Phone CIRCUIT HANDSET CIRCUIT TONE GENELATOR DPITS communi ...

Page 57: ...1 5 2 6 3 7 4 8 ...

Page 58: ...9 13 10 14 11 15 12 16 ...

Page 59: ...17 21 18 22 19 23 20 24 ...

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