Radio Shack 26-1061 Service Manual Download Page 14

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Summary of Contents for 26-1061

Page 1: ...Radio hack Service m B MODELIDE MICROCOMPUTER Catalog Numbers 26 1061 1062 1063 CUSTOM MANUFACTURED IN U S A r BY RADIO SHACkHa DIVISION OF TANDY CORPORATION Q ...

Page 2: ...ontrol and Data Buffering 43 Non Maskable Interrupt Logic 43 Drive Select Latch and Motor On Logic 43 Wait State Generation and WAITIMOUT Logic 44 Clock Generation Logic 44 Disk Bus Selector Logic 44 Read Write Data Pulse Shaping Logic 44 Disk Bus Output Drives 44 Write Precompensation and Clock Recovery Logic 44 Floppy Disk Controller Chip 45 Adjustments and Jumper Options 45 Floppy Disk Interfac...

Page 3: ...ndle Drive 97 Positioner Control 97 Data Electronics 93 Data Recording 99 Data Reproduction 99 Operation 101 Interface Electronics Specifications 101 Input Control Lines 101 SELECT Lines DS1 DS4 101 Drive Motor Enable MOTORONl 101 Direction and Step DIR STEP 101 Compensated Write Data CWD 101 Write Enable WG 101 Side Select SDSEL 103 Output Status 103 Index Pulse IP 103 TRACK 00 TRK0 103 Write Pro...

Page 4: ...uits 31 5B Model III CPU Schematic Diagram Processor Section 32 5C Model III CPU Schematic Diagram RAM Section 33 5D Model III CPU Schematic Diagram Address Decoding Section 34 5E Model III CPU Schematic Diagram Video Section 35 5F Model III CPU Schematic Diagram Keyboard Section 36 5G Model III CPU Schematic Diagram Cassette Interface Section 37 5H Model III CPU Schematic Diagram Line Printer and...

Page 5: ...y SECTION IX FLOPPY DISK DRIVE 1 PC Board Component Locations Logic Board 94 1 A PC Board Components Locations Servo Boards 95 2 Resistor Termination 6 3 Cable Assembly Connector Pin Removal Chart 96 4 5 6 Write Timing Diagram 8 Interface Configuration iM 9 10 11 Cat s Eyes Pattern M 12 Radial Adjustment ltJJ 13 14 15 16 Upper Arm and Carriage 17 13 13 19 Servo Board Schematic 122 20 Mini Disk Dri...

Page 6: ...ECTION V RS 232C CIRCUIT BOARD BRG Programming Table 65 SECTION VI POWER SUPPLY 1 Load Board Values gg 2 Voltage and Ripple Specifications 69 SECTION IX MINI DISK DRIVE 1 Interface Connector Pin Assignments 102 2 Power Connector Pin Assignments 102 ...

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Page 8: ...SECTION I INTRODUCTION ...

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Page 10: ...lowing standard features 12 key numeric keypad for rapid entry of numbers Rugged cabinet housing keyboard electronics video display and power supply Direct drive video monitor for Improved resolution Internal power supply Parallel printer port for use with Radio Shack printers Several other features are available when Level II BASIC is used features such as real time clock upper and lower case cha...

Page 11: ... cc B m J c a o O 3 S o cc J t JS w I LLI CO z cc m O i CO CN W CC i nj cc 2 w J a cc t 3 0 1 cc lu 9 o 2 O cc _i a I a u z o O o I to c o D CZD g cc 5 o o _i CQ LU Q O o CO tr i LU cc C5 2 g S 2 S a 2 ...

Page 12: ...SECTION II DISASSEMBLY REASSEMBLY 5 ...

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Page 14: ... remove all cables connecting the RS 232 Board 2 Remove the screws connecting the PC Board to the chassis and remove the Board MAIN POWER SUPPLY 1 Remove all interconnect cables to the Boards fastened on the metal chassis bracket power supply cable video keyboard and cassette cables and if applicable RS 232 and FDC power connectors and the Disk ribbon cable 2 Remove the four screws fastening the m...

Page 15: ...nect one end of a wire to a known good ground and connect the other end of the wire to the blade of a common screwdriver Insert the screwdriver blade under the suction cup and touch it to the clip holding the wire to the CRT 3 Insert a common screwdriver under the suction cup on the high voltage anode wire on the side of the CRT Use the screwdriver to compress the clip holding the wire to the tube...

Page 16: ...oard MAIN POWER SUPPLY 1 Fasten the Power Supply to the metal chassis bracket using four 6 x 1 4 screws Be sure the ground tab is fastened back in place 2 Install the chassis bracket with all Boards in place in the case bottom using four 6 x 1 4 screws 3 Reconnect all cables power supply video keyboard and cassette cables and RS 232 and FDC power cables and Disk ribbon cable if necessary DISK DRIV...

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Page 18: ...SECTION III CPU CIRCUIT BOARD 11 ...

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Page 20: ... fall times The reset switch which is located on the keyboard is ORed with power on reset R7 C54 U15 to provide a System RESET signal The Reset pin on the Z 80 is driven by RESET The address lines are buffered by LS244 s U91 U92 the data lines by an LS245 U90 and control lines buffered by an LS367 U76 The buffered control lines are combined in U89 and U86to form memory and IO port controls RD WR I...

Page 21: ...is the only one suitable tor 4K RAMs jumper option U to T N to P GG to FF The ROM strobes ROMA ROMB and ROMC are generated by the remaining section of the LS139 U58 and part of the LS145 U60 The combinational logicbelowU60 U75 U73 U72 U74 U86 deletes two addresses from ROMC 37E8 and 37E9 which correspond to the line printer address thus ROMCP is the actual strobe going to the 16K bit ROM The resul...

Page 22: ...egister Port 0F2H Disk Sector Register Port 0F3H Disk Data Register Name Port Address Access Description RS232IN 0E8H to0EBH Read Only Read UART Registers Port 0E8H Modem Status Port 0E9H N A Port 0EAH UART Status Register Port 0EBH UART Receiver Holding Register Resets D R Name Port Address Access Description RS2320UT 0E8H to0EBH Write On y UART Control Data Modem Control BRG Control Port 0E8H UA...

Page 23: ...Hz and results in 80 char acters per line 64 displayed and 16 blanked The line count L1 to L8 runs modulo 12 i e twelve horizontal lines per character block The row counter R1 to RS and VDRV runs modulo 22 60 Hz or modulo 26 50 Hz depending which jumper option A or B or C has been selected C The character generation logic consists of a latch LS273 U68 to hold the ASCII data a ROM which contains th...

Page 24: ...ge equal to the average signal level with R46 and CR9 providing fast charge and R48 providing a slow discharge Capacitor C93 provides an equivalent AGC action since the comparator threshold becomes proportional to the signal level The comparator outputs negative pulses cor responding to the input pulses which are then inverted by U2 and fed into the clock of a D flip flop U3 The D flip flop will t...

Page 25: ...and enabled also by ENEXTIO External IO waits and interrupts are also supported by the 10 Bus via U87 and U88 Refer to the de tailed 10 Bus description and timing diagram The jumper positions vary between 4K and 16K RAM models Jumpers should be installed as described below 4K RAM UtoT Nto P GG to FF 16K RAM StoT RtoP EEto FF The CRT positioning jumpers also very between the 50Hz and 6QHz models Ju...

Page 26: ... The address fine data tine and control lines a to c and e to g are enabled only when the ENEXIO bit in EC is set to a one To enable 10 interrupts the ENJOBUSINT bit in CPU IOPORT E0 output port must be a one However even if disabled from generating interrupts the status of the IOBUSINT line can still read on the appropriate bit of CPU IOPORT E0 Input port See Model III Port Bit assignment for por...

Page 27: ... WAfT _ f v_ _ MM _ OUT v_ Inwrwd by 80 CPU input or Output Cycles with Wait States A AT 101 0 DATA BUS DATA BUS tEXTIOSEL V V JL OUT CD y y BEAD CYCLE WHITE CYCLE HEAD CYCLE WHITE CYCLE IniMtid by 280 CPU tComcKknt wilh tOHQ antv on INPUT CYClt FIGURE3 10 BUS TIMING DIAGRAMS 20 ...

Page 28: ...external IO Bus 1 enables Bit 3 ENALTSET disables alternate character set 1 enables alternate video character set Bit 2 MODSEL enables 64 character mode 1 enables 32 character rnode Bit 1 CASMOTORON turns cassette motor off 1 turns cassette motor on Bit Undefined Name RDINTSTATUS Port Address 0E0H Access READONLY NOTE A indicates the device is interrupting Bit 7 Undefined BitG RS 232 ERROR INT Bit...

Page 29: ... WSGEN no wait states generated 1 wait states generated Bit 5 PRECOMP no write precompensation 1 write pr compensation enabled Bit 4 SDSEL selects side of diskette 1 selects side 1 of diskette Bit 3 Drive select 4 Bit 2 Drive selects Bit 1 Drive select 2 Bit Drive select 1 Bit 1 ENCASINTF 1 enables 1500 Baud falling edge inter rupt disables above Bit ENCASINTR 1 enables 1500 Baud rising edge inter...

Page 30: ...23 in d CO I z LU z o a O O I Q o 3 O QC O Q tu 1 cc Q o Lll cc ...

Page 31: ...LU 9 CO D O cr o Q o CQ D O CC p D LU 1 z CC a D a o CC D C3 24 ...

Page 32: ... 50V Monolithic 0 1 iF 50V Monolithic 33pF Ceramic Disc O ljuF 50V Monolithic 0 1mF 50V Monolithic 0 1mF 50V Monolithic 0 001 juF Ceramic Disc 0 001 uF Ceramic Disc 0 1juF 50V Monolithic 0 1 wF 50V Monolithic 200pF Ceramic Disc Q 1juF 50V Monolithic 47O0pF Ceramic Disc D ljuF Ceramic Disc O OljuF Ceramic Disc 8384104 832 5471 8384104 8384104 832 5471 8384104 3384104 832 6221 8384104 S384104 838410...

Page 33: ...isc Not Used I Not Used 10 iF 16V Electrolytic radial 10 F 16V Electrolytic axial 1D uF 16V Electrolytic radial J 10 fF 16V Electrolytic radial 10 iF 16V Electrolytic axial 1Q uF 16V Electrolytic axial 10 UF 16V Electrolytic radial 10jLtF 16V Electrolytic radial 10juF 16V Electrolytic axial 10 iF 16V Electrolytic radial 10 uF 16V Electrolytic axial 10jUF 16V Electrolytic radial 70 uF 16V Electroly...

Page 34: ... ADX 1152 ADX 1152 INTEGRATED CIRCUITS U1 U2 U3 U4 U5 U6 U7 U14 U15 U16 U17 U18 U19 U20 U21 U22 U23 U24 74LS74 Dual D Flip Flop 74LS04 Hex Inverter 74LS74 Dual D Flip Flop 74LS157 Quad 1 of 2 Data Selecter 74LS93 Binary M6 Counter 74LS10 Tripe 3 in put NAN D gate 416 RAM 416 RAM 74LS132 Quad 2 input NAND 74LS00 Quad 2 input NAND gate 74LS74 Dual D Flip Flop 74LS00 Ouad 2 input NAND gate 74LSQ8 Qua...

Page 35: ...CD Decimal Decoder Driver U61 74LS175 Hex Quad D Flip Flop U62 74LS90 Decade H2 Binary Counter U63 8T26 Bus Transceiver U64 8T26 Bus Transceiver U65 MC14050B U66 74LS240 Octal Buffer U67 74LS245 U68 74LS273 U69 74LS157 Quad 2 line to 1 line Data Selector Multiplexer U70 74LS157 Quad 2 line to 1 line Data Selector Multiplexer U71 74LS157 Quad 2 line to Hine Data Selector Multiplexer MANUFACTURER S ...

Page 36: ...lop 802 0273 U95 74LS244 Line Driver 8020244 U96 L M339 805 0339 U97 MC75452 8050452 U98 74LS174 Hex Quad D Flip Flop 8020174 U99 74LS244 Line Driver 8020244 U100 74LS174 Hex Quad D Flip Flop 8020174 U101 74LS245 8020245 U102 74LS244 Line Driver 8020244 U103 74LS367 J Tri State Hex Buffer 8020367 U104 ROM A MCM364 804 1364 U105 ROM B MCM332 804 0332 U106 R0MC MCM68A 804031 6B U107 74LS32 Quad 2 in...

Page 37: ... 7 K WW 5 Carbon Film 4 7 K WW 5 Carbon Film 10K WW 5 Carbon Film 10K WW 5 Carbon Film 51 K Ww 5 Carbon Film 10K WW 5 Carbon Film 4 7K WW 5 Carbon Film 620K WW 5 Carbon Film 10K WW 5 Carbon Film 8 2K WW 5 Carbon Film 6 8K WW 5 Carbon Film 56K WW 5 Carbon Film 56K WW 5 Carbon Film 1 5M WW 5 Carbon Film IK Ww 5 Carbon Film 15K WW 5 Carbon Film MANUFACTURER S PART NUMBER 820 7247 820 7227 820 7247 82...

Page 38: ...MBER 820 7115 820 7310 820 7122 820 7247 820 7322 820 7047 820 7030 841 9014 RELAY TRANSISTORS 2N3906 MC7905C MISCELLANOUS Cable 3 position 3 75 Cable 3 position 8 5 Jumper Plugs 10 Socket 40 pin 1 Socket 24 pin 4 Socket 20 pin 3 Socket 18 pin 2 Socket 1 6 pin 24 1 820 7122 829 0009 829 0009 829 0009 829 3247 829 0015 829 0010 842 9102 810 0906 805 1905 845 9008 845 9108 851 9098 850 9002 850 9001...

Page 39: ...1 All capacitors are in micro farads and all resistors are in ohms unless otherwise noted 2 On Revision F boards only U62 pins 6 and 7 are connected and pin 6 is not at ground FIGURE 5B MODEL III CPU SCHEMATIC DIAGRAM PROCESSOR SECTION 32 ...

Page 40: ...CID3 33H T BIT 7 16 K WOO TFFF BOOO BFFF COOO FFFF IDK FIGURE 5C MODEL III CPU SCHEMATIC DIAGRAM RAM SECTION 33 ...

Page 41: ... lES EB WR Nlfil MAS E8 EVE73 WR INT f ABK 71EG fEf E3J A 01 CAS IN K LP IN RTC IF Wa232 RDNMX5TATU3 Tin rw ts T rr us 61 RDM C U73 N JfrL uiz 30 4 JJI07 a y AZ A3 AM A9 C 1 21 O 3 i_ P KI7 L 75 LP OK LT RD 1 hz z VIA A3 MAS FIGURE 5D MODEL III CPU SCHEMATIC DIAGRAM ADDRESS DECODING SECTION ...

Page 42: ...FIGURE 5E MODEL III CPU SCHEMATIC DIAGRAM VIDEO SECTION 35 ...

Page 43: ...3 A it A H i w A 7 _73 7K M A T 7f a A CABLE THESE FARTS MOUNTED ON PROCESSOR BCWKD VBD __l l sg RESET SWITCH t s j c IS 20 T H ABOVE KEYS MODES ARE CONNECTED IN PARALLfl WITH THE SIMILAR KEYS OF THE KEYBOARD MATRIX n r e 3250 TXfA Z IA D2A JD3A DBA DSA r 7A FIGURE 5F MODEL III CPU SCHEMATIC DIAGRAM KEYBOARD SECTION 36 ...

Page 44: ...H3 I NTATA TUB CA 0UT8 WfD ourii MOD SCL FIGURE 5G MODEL III CPU SCHEMATIC DIAGRAM CASSETTE INTERFACE SECTION 37 ...

Page 45: ...N OR LP RDit B0A LS 3G7 C2A LSZ44 L q5 a X P T 3T UWtT SELECT JT r X 7 p vw _r DAT STRHBC K43 5V 20K T vw o 4Z L o o o o a o JJ o J2_1 a t MZ MZ fiZ o o Jl T L WC PRINTER FIGURE 5H MODEL III CPU SCHEMATIC DIAGRAM LINE PRINTER AND REAL TIME CLOCK SECTION 38 ...

Page 46: ...EMEN EZ 2 50 VI D2 B3 TJ4 D7 D5 Dfi rji D2 U3 B4 D5 D7 5V RPS l7 I8 i I6 l5 j I3 i2 1 D7A D 4 D5A D4A D3A JJ2 1 M DOA NC TP2A JP2B O J PIE _ e o D0A rj4A D7A D6A D3B CD5B JD B CTJZB FIGURE 5J MODEL III CPU SCHEMATIC DIAGRAM I O BUS SECTION 39 ...

Page 47: ...KDINTS 7ATUS SPORE INT A v CPU BOARD raoo c oi ftoa cz 3 czoq cad czix cz 4 j C2 b cai7 r T fluT T T T t i T 3 t t t T Ifo T 4b T t r dob tie i 273 D3B JJ fB D5B XfiB D7B DISK IM TJIS K Ci T 40 XI YYIT KESET I VT 1KX WRNMnMSKREe DRfSEL U XT SIS GNU 10 IS RTJ VIY T_STATU5 U r I Z R K 17 T 1r V2 k s U q f ID K i 13 i e U 0_ T PZ a vl G l S J ds S O D 4 jf i y _ V y s2_ CPU BJ l RI3 AT zrz P 20 V EC ...

Page 48: ...SECTION IV FLOPPY DISK INTERFACE 41 ...

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Page 50: ...oth signals are inactive logic high U2 is enabled to receive data from the CPU data bus NONMASKABLE INTERRUPT LOGIC A dual D flip flop U5 is used to latch data bits D6 and D7 on the rising edge of the control signal WRNMIMAS REG The outputs of U5 control the conditions which will generate a non maskable interrupt to the CPU The NMI interrupt conditions are programmed by doing an OUT in struction t...

Page 51: ...control pin for the data selector If U22 pin 1 is low the external inputs are selected other wise the internal inputs are selected This control signal labeled EXTSEL is derived from the outputs of the Drive Select Latch If Drive 2 or Drive 3 is selected U17 pin 1 will go low indicating that an external drive is selected One half of U10 a five input NOR gate is used to detect when any of the four d...

Page 52: ...ll eventually correct the VCO input to exactly the same frequency multiple asthe FDD signal The leading edge of the RDD signal will then occur in the exact center of the RCLK window an ideal condition for the 1793 inter nal recovery circuits ADJUSTMENTS AND JUMPER OPTIONS The Data Separator must be adjusted with the 1793 in an idle condition no command currently in operation Adjust R7 potentiomete...

Page 53: ... 04 XT SIS GND V P7 T Q K ie K K K 17 T I I I s S 1 2 K e f 10 r 7 wa r g J 7 r J V T2 T TL 2 1 B J J IS 1 16 n 0 y e 4 v 7 JZ _7 vz f 23 JB I DZ 1 3 r 4 JDS 2JG D7 XI5K OUTX A0 Al Ml K SET x vt k Wfi MMIM AHK KEG RDNWIIGTAnjSrt DRVSEL WfiZT SIG GND CPU BWT D C 1BLE FLOPPY JDISK CONTROLLER INTERFACE ZCARX FIGURE 1 FDC BOARD TO CPU BOARD SIGNAL DESCRIPTION 46 ...

Page 54: ... FIGURE 2 FLOPPY DISK INTERFACE PC BOARD COMPONENT SIDE 47 ...

Page 55: ...FIGURE 2 FLOPPY DISK INTERFACE PC BOARD CIRCUIT SIDE 48 ...

Page 56: ...31 830 1104 8384104 8354471 8384104 8384104 830 1104 8384104 830 1474 832 6101 832 6101 830 3104 ACC104QJAP ACC104QJAP ACC104QJAP ACC104OJAP ACC104GJAP ACC104QJAP ACC101QJCP ACC1G4QJAP ACC104QJAP ACC104QJAP ACC101OJCP ACC104QJAP ACC471QJCP ACC106QDAP ACC106QDAP ACC103QJCP CONNECTORS J2 J3 20 pos right angle 4 pin right angle header 851 9078 851 9079 AJ6977 CRYSTAL Y1 4 MHz 840 9010 AMX2804 DIODES ...

Page 57: ...5 R16 R17 R18 R19 R20 2 2K 1 4W 5 150ohm 1 4W 5 150 ohm 6 pin resistor network 2 2K 1 4W 5 1 0K Trim Pot 50 K Trim Pot 100K Trim Pot 10K 1 4W 5 47K 1 4W 5 47 K 1 4W 5 10K 1 4W 5 10K 1 4W 5 47 ohm T 4W 5 270K 1 4W 5 150 ohm 10 pin resistor network 10K 1 4W 5 910 ohm 1 4W 5 910 ohm 1 4W 5 2 2K 1 4W 5 22 K 1 4W 5 820 7222 820 7115 829 0012 820 7222 827 9310 827 9350 827 9410 820 7310 820 7347 820 734...

Page 58: ...J pfiofKEcamp Jt l i l2v DI0 oiiy D12 Oi3 y 13 DI7 IDRVSEL 2 JPRT U22 JH 35 3H 21 IP TRW uz 3Z HLT f DY c cm pi D2 7Z 93 D3 Qv D5 Q5 CLR 10 II FrW iriFM IS A HI Cf6 C 5 Hi 4 1 CLR 1 HI J re r2 i ra L T X 75 DS2 OS I 2 Tf f 3 1 J 5 JJ CUD I v V STEP J p DIR Z v UG Z Z7 32 30 SDSEL 1 I RD s TPt ciezZ C 1C2 I T T T w rP5 I UPHT 2g i r K0 2 xm i z 2 270K 5f Ull i UDOUT 4 Y 3 A HI p a 23 B J A HI 2 6 j...

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Page 60: ...SECTION V RS 232C CIRCUIT BOARD 53 ...

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Page 62: ...TR1602 needs are supplied by the Baud rate generator BR19411 This circuit takes the 5 0683 MHz supplied by the CPU board and the programmed information received from the CPU over the data bus and divides the basic clock rate to provide two clocks The rates available from the BRG go from 50 Baud to 19200 Baud See the BRG table for the complete list BRG PROGRAMMING TABLE NIBBLE LOADED TRANSMIT OR RE...

Page 63: ...nsferring data to or from the UART The interrupt mask register is port E 3 write and the interrupt status register is port E0 read Refer to the 10 Port description for a full breakdown of a 13 interrupts and their bit positions The Model III RS 232C board is functionally identical to the Model I RS 232 board with the following exceptions Interrupts are supported there are no sense switches for con...

Page 64: ...tput to this port determines the receiver Baud rate while the high order nibble determines the trans mit Baud rate PORT EAH OUTPUT UART AND MODEM CONTROL INPUT UART STATUS An output to this port loads the UART Control register if the enable bit for this function is set D1 port E8H 1 The UART Control register is five bits wide D7 D3 leaving three bits for modem control D2 D0 Three more modem contro...

Page 65: ... Overrun error 1 condition true Framing error 1 condition true Parity error 1 condition true Not Used Not Used Not Used 1 condition true PORT EBH OUTPUT TRANSMITTER HOLDING REGISTER INPUT RECEIVER HOLDING REGISTER An output to this port loads the UART Transmitter Holding register with a word to be transmitted as soon as the last word loaded in the Holding register is transmitted This register shou...

Page 66: ...HIMTM SX REG KDIIVT 57 ATTIS SP 1 _ V V RS 232 C INTERFACE BOAWD K K K _5 10 _I2 IB _20 3 IZ 16 2 0 1 J V T PB 10 II vi 15 vl 19 J 1 V y C BL io 3 0 rjQB D IB D2B D3B D4B JD5B D SB P7B KS232 01 T RS232 IN SIG GAUD CLOCK E SPARE I5 RESET n WHiivTM tSK res h KDINT5 TA TUS 11 S PA RE INT CPU BO ffiD FIGURE 1 RS 232 BOARD TO CPU BOARD SIGNAL DESCRIPTION 59 ...

Page 67: ...FIGURE 2 RS 232C PC BOARD COMPONENT SIDE 60 ...

Page 68: ... BBBB flBBtB8BgB9l Sfl l9tBB la o j o T a FIGURE 2 RS 232C PC BOARD CIRCUIT SIDE 61 ...

Page 69: ...7404 Hex Inverter 74LS139 Dual Decoder 74LS368 Hex Buffer 74LS174 Quad D Flip Flop MC1489 Quad Line Driver MC1488 Quad Line Driver 74LS27 NOR gate 74LS38 NAND Buffer MC1489 Quad Line Driver MC1488 Quad Line Driver 851 9030 851 9078 851 9079 804 6941 804 5602 802 0244 802 0367 802 0367 8024174 802 0139 802 0368 802 0174 805 0189 805 0188 802 0027 802 0038 805 0189 805 0188 RADIO SHACK PART NUMBER A...

Page 70: ... I2V QHD WV raj y v v y y y y P3 ev SKD 12 V 1NEBK 0UTCA PERIPHERAL FIGURE 3 MODEL III RS 232C SCHEMATIC DIAGRAM 63 ...

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Page 72: ...SECTION VI POWER SUPPLY 65 ...

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Page 74: ...e Need X10and X100 probes 5 Load Board with Connectors See Table 1 for values of loads required The entry on the table for Safe Load Power is the minimum power ratings for the load resistors used 6 Ohmmeter SET UP PROCEDURE Set up as shown In Figure 1 You wiil want to monitor the input voltage and the output voltage of the regulated bus which is the 5 output with DVMs Also monitor the 5 output wit...

Page 75: ...3 If this waveform is not present check L2 Q1 r and D1 and secondary components Q3 D8 D9 D10 and L3 If any of the semiconductors are found shorted or inductors open replace them A Check Fusable Resistor If fusable resistor is blown replace but do not apply power until cause of failure is found B Preliminary Check on Major Primary Components Check diode bridge BR1 power transistor T2 and catch diod...

Page 76: ... Load 12 Load 12 Load 1 96VAC Max Max Max 2 128VAC Max Max Max 3 120VAC Max Min Min 4 128VAC Min Min Min 5 95VAC Min Min Min TABLE 2 VOLTAGE AND RIPPLE SPECIFICATION OUTPUT MIN MAX NO LOAD RIPPLE 5 4 75V 5 25V 50mV P P 12 11 40V 1 2 60V 150mV P P 12 1 1 00V 1 5 00V 150mV P P Applies to resistive load only Not under system operating conditions ...

Page 77: ...0010 20100010 10T0O370 00100060 IC1 TL431CLP RESISTORS R1 47 ohm 1W R2 150K 1 2W R3 1K 1 4W R4 not used R5 82 ohm 1 4W R6 27ohm 1 4W R7 3 3 ohm 1 2W R8 10 ohm 1 4W R9 27 ohm 2W R10 0 15 ohm 1 2W R11 270ohm 1 2W R12 82 Ohm 1 4W R13 270ohm 1 2W R14 8 2ohm 1 4W R15 560ohm 1 4W R16 56 ohm 1 4W R17 56 ohm 1 4W R18 12K 1 4W R19 12 ohm 1 4W R20 470ohm 1 4W R21 4 7K 1 4W R22 2 7K 1 4W R23 68 K 1 4W R24 22...

Page 78: ...zx N WJ K N W K W 5 oc 3 Q O LU X o GO Q a D GO cc LU o Q LU GE O 71 ...

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Page 80: ...SECTION VII VIDEO MONITOR 73 ...

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Page 82: ...io P4 phosphor integral implosion protection Operating Temperature 41 Fto 131 F 5 C to 55 C ambient Humidity 95 non condensing at 41 F to 104 F 5 C to 40 C Operating Altitude 10 000 ft 3046 meters maximum Power Input 12 VDC at 1 amp nominal TTL Level Input Signals 4 volts 1 5 volts Horizontal 4 to 25 sec positive going Vertical 100 to 1400jLtsec negative going Video positive white Video Response B...

Page 83: ...FIGURE 1 VIDEO MONITOR PRINTED CIRCUIT BOARD 76 ...

Page 84: ... slide linearity sleeve for side See Loosen deflection yok ward or backward to equalize character spacing on left side of to match character spacing on right side of screen T Figure 2 for location of linearity sleeve Note Check horizontal linearity prior to width adjustment Adjust width control to produce horizontal scan of approx imately 8 inches CENTERING Adjust centering rings on deflection yok...

Page 85: ... SHOULD HOLD WITHIN 20 o 4 ALL RESISTORS 1 4 WATT UNLESS OTHERWISE INDICATED INDICATES GROUND INOICATES 5 TOLERANCE INDICATES 2 TOLERANCE INDICATES I TOLERANCE C RELATES TO ZONING ON PERIMETER OF DRAWING i SERVICE TECHNICIAN WARNING X RADIATION PRECAUTION THIS PRODUCT CONTAINS CRITICAL MECHANICAL AND i ELECTRICAL PARTS ESSENTIAL FOR K RADIATION PROTECTION SEE PAGE 6 OF SERVICE DATA FOR SPECIFIED R...

Page 86: ...SECTION VIII ILLUSTRATED PARTS CATALOG 79 ...

Page 87: ......

Page 88: ...00 o en LU CO CO m CO O cc LU I O C3 81 ...

Page 89: ...CO W C5 ex O H LXJ CM 82 ...

Page 90: ... J a CO CM LO 1 IN Llj T CO H CO CM v i LLl H _i Q LU CO CO VtA n m LU cc 3 wA u 83 ...

Page 91: ...2 LL W3 GO o 2 LU 84 ...

Page 92: ...so en 3 a Q 1 UJ 85 ...

Page 93: ...T NUMBER 8492002 8569077 8492002 8589038 8579021 8529020 8719104 RADIO SHACK PART NUMBER AXX8010 AHD1618 AXX8010 AHD8548 AHD7180 AHC0329 AZ56S9 FIGURE 3 BASE PLATE ASSEMBLY ITEM NUMBER DESCRIPTION 116 Screw 6 x 1 f4 plastite 120 Knob Thum bwhee I 121 Video Control Bracket 123 Label RAM size 16K 124 Keyboard 65 key Screw 6 x 1 2 plastite 125 Keyboard Bezel 126 Keyboard Header right angli 127 Mylar ...

Page 94: ...HC0787 ART3082 AHD7168 AXX0511 AXX0510 NOTE If your computer Is earlier the Rev F the following hardware may be used on your unit instead of the starred items PCB Mount Bracket Screw 6 x 1 4 plastite Clip RICHCO LCBS 20R Fastex 16404 08 Clip RICHCO LCBS 4R Fastex 16402 04 729042 8569077 8559017 8559022 8559018 8559020 ART308O AHD1618 AHC0070 AHC0075 AHC0071 AHC0073 FIGURE 5 DISK DRIVE ASSEMBLY ITE...

Page 95: ... Wire Harness DCPwer Harness Disk DC Power Harness Main Ground Harness Disk Ground Harness Keyboard Ground Harness Main Ground Harness Secondary Disk Keyboard CPU shielded MANUFACTURER S PART NUMBER 8729054 8559028 8559027 8529024 3529026 8519062 CABLES 8709151 8709156 8709153 8709155 8709178 8709204 8709194 87091 61 8709195 8709182 RADIO SHACK PART NUMBER AHC0358 AW2214 AW2531 AW2538 AW2356 AW253...

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Page 98: ...SECTION IX MINI DISK DRIVE 91 ...

Page 99: ......

Page 100: ...tivates the cone clamp system which centers and clamps the diskette to the drive hub The drive hub is driven at a constant speed of 300 rpm by a servo controlled DC motor In operation the magnetic head is loaded into contact with the recording medium whenever the front latch is closed A 4 phase stepper motor band assembly and its associated electronics position the magnetic head over the desired t...

Page 101: ...near 2 C41 J3I I NCR12 TP2 C18 uuuuuuwuu 1 1 or ococ I M no ci9 R8 TTli R29 R30 R2I 02 Ql CN TO n C4 Hcrh 7 is C8 C7 i0 TP 1 o ci w w I I TP4 OL S I I IP10 I o I TP3 C39 coo to I I A fO CNOJii I I lXV_ QT I R58 33 A C23 I i R55 Mcri6 K s V sX CO h C 25 i C 26 R20 Oi _ or r58 C27 oI z MCR 6 TP12 54 CR18 C o zJ5 5 7 t jtp8 A R36 44 J i 28 R23 R21 C 13 C 14 0 r 6 C29 C20 TP11 C1 ScR20 R22 C30 C 11 C3...

Page 102: ... BOARD COMPONENT SIDE R4 SPINDLE SPEED CONTROL D R6 4zzn cs CZ C6 E B ZJ R9 H L_ r 1 C4 R3 R Ul rs r R14 t 3 R12 _ h h h RIC r R2 L h h LI 7H R13 R 11 4 3 n czf Rl Zh LINEAR SERVO BOARD COMPONENT SIDE SERVO JUMPER DRIVE MOTOR FIGURE 1A P C BOARD COMPONENT LOCATIONS 95 ...

Page 103: ... Resistor Termination in the IC socket is used in the last drive in the system only It must be removed for Drive two when two external drives are used IMote The internal drives in the Model III are not terminated RESISTOR TERMINATION IN SOCKET REMOVE EX CEPT FOR LAST DRIVE IN SYSTEM C J J 3 L r r a B 7 D J J c j r 34 32 30 28 26 24 70 1ft 16 14 12 10 8 6 4 2 FIGURE 2 RESISTOR TERMINATION FLAT RIBB...

Page 104: ...otransistor causing it to conduct The signal from the Index Phototransistor is passed to the Pulse Shaping Network which produces a pulse for each hole de tected This pulse is presented to the user on the INDEX PULSE interface line WRITE PROTECT A Write Protect signal is provided to the user system via the WRITE PROTECT interface line The write protect circuitry consists of a Write Protect Sensor ...

Page 105: ...e using a double frequency code Figure 5 illustrates the magnetization pro files in each bit cell for the number sequence shown The erase gaps provide an erased guard band on either side of the recorded track This accommodates the tolerances in track positioning All signals required to control the data electronics are pro vided by the user system and are shown in the Block Dia gram Figure 4 These ...

Page 106: ...this enables the Write Current Source Since the trim erase gaps are behind the read write gap TRUv ERASE control goes trite 390 Sec after the WRITE ENABLE interface line It should be noted that this value is optimized between the requirements at Track 00 and Track 40 so that the effect of the trim erase gaps on pre vious information is minimized Figure 6 also shows the information on the WRITE DAT...

Page 107: ...AK TO PEAK 4 u SECONDS MINIMUM B u 5ECON05 MAXIMUM FIGURE 6 WRITE TIMING DIAGRAM LINEAR OUTPUT FROM FILTER OUTPUT FROM DIFFERENTIATOR READ DATA INTERFACE NOTE 1 wv I w I I I III IT ij IHHj ir i i i t iii NOTES t 250 MILLISECONDS AFTER DRIVE MOTOR STARTS OR 20 MILLISECONDS AFTER STEP COMMAND OR 100 u SECONDS AFTER TERMINATION OF WRITE BUSY WHICHEVER IS THE LATEST TIME FIGURE 7 READ TIMING DIAGRAM 1...

Page 108: ...lse with a time duration greater than 200 nSec on the STEP line initi ates the access motion The direction of motion Is deter mined by the logic state of the DIRECTION line when a STEP pulse is issued The motion is towards the center of the disk if the DIRECTION line is in the true low state when a STEP pulse is issued The direction of motion is away from the center of the disk if the DIRECTION li...

Page 109: ...20 STEP STEP 21 22 COMPENSATED WRITE DATA CWD 23 24 WRITE GATE WG 31 32 SIDE SELECT SDSEL 33 34 Spare Disk Drive to Controller Ground Signal Description Mnemonic 7 3 INDEX PULSE IP 25 26 TRACK 00CTRK0 27 28 WRITE PROTECT WPRT 29 3D READ DATA RD 33 34 Spare TABLE 1 INTERFACE CONNECTOR PIN ASSIGNMENTS J1 external J4 internal Pin Supply Voltage 1 2 3 4 12VDC Return 12 VDC Return 5 VDC 5 VDC TABLE 2 P...

Page 110: ...face signal indicates to the controller that the read write head is positioned at Track 00 The Track 00 remains true low until the head is moved away from Track 00 WRITE PROTECT WPRT When the Disk Drive is selected this signal line logic level goes true low when the diskette is write protected The write electronics are internally disabled when the diskette is write protected NOTE It is recommended...

Page 111: ......

Page 112: ...ffer ential output of the first stage of read signal amplifi cation Motor On TP13 This signal is low true for the motor on condition Track 00 TP8 This signal is low true when the carriage is positioned at track 00 and the step motor phase is correct Analog Ground TP10 The analog ground reference point is provided for measuring read write waveforms Step Pulse TP1 2 When stepping in or out the signa...

Page 113: ...P12 TP9 Tiiiiiiiiiiiiin J1 INTERFACE CONNECTION TP2 TP 1 TP8 5 9 TP4 TP10 TP3 o LU s Z Q s g C 5 LU 0 1 Z o t O m hi 1 1 1 o S CL STEPPER MOTOR SERVO JUMPER J4 J2 POWER CONNECTOR COMPONENT SIDE FIGURE 9 LOGIC BOARD TEST POINTS AND CONNECTOR LOCATIONS 106 ...

Page 114: ...E SPEED CONTROL SERVO JUMPER DRIVE MOTOR NON LINEAR SERVO BOARD COMPONENT SIDE R4 SPINDLE SPEED CONTROL O SERVO JUMPER DRIVE MOTOR LINEAR SERVO BOARD COMPONENT SIDE FIGURE 10 SERVO BOARD CONNECTOR LOCATIONS 107 ...

Page 115: ...e jitter on the lead ing edge of the third pulse The leading edge of the pulse should start S tsec 240nsec from the trigger puise The third pulse jitter should be less than 480nsec edge to edge ISOnsec Bfisin 4 If jitter is excessive replace drive belt motor Servo PCB or spindle as necessary ALIGNMENT AND ADJUSTMENT To perform the alignment and adjustment procedures you will require the following ...

Page 116: ... to track 00 Return to track 16 and re verify the pattern 5 Step to track 34 40 and return to track 16 Re verify the cat eyes pattern If Radial Needs Adjustment a Loosen the two retaining screws on back of the unit and the retaining screw on the carriage as sembly b Turn the Adjustment Cam until the cat eyes pattern is within 75 If the pattern does riot come within spec loosen the hex head screw o...

Page 117: ...stop screw in until the output amplitude shown on the scope starts to decrease Back the track QQ stop screw out until the ampli tude stops increasing Back the track 00 stop screw out one half turn from this point 1 Set Scope Vert at 0 2 volts div Time Base 50Msec div 2 Insert alignment diskette and read track 01 Scope display should show volts AC trace for 200jUsec i 50jL sec If waveform is outsid...

Page 118: ...d arm 15 grams is approximately equal to the weight of a 25 cent peice 4 Observe the amplitude If it increases more than 10 the compliance needs to be adjusted 5 To adjust the compliance loosen the two nuts that hold the head load arm in place While mon itoring the amplitude move the arm until output is highest Hold the arm in this position and tight en the nuts 6 Re verify compliance If complianc...

Page 119: ... Monolithic I 0 01 iF 50V Monolithic C35 C36 4 7 uF 20V Electrolytic Axial C37 4 7 uF 20V Electrolytic Axial C38 6 8 35V Tantalum C39 6SfiF 35V Tantalum C40 330pF B0V Monolithic C41 330pF 50V Monolithic 339 5223 838 1474 838 1684 838 4474 8384474 838 3104 8384474 838 4474 838 2474 838 3104 838 1274 838 1474 838 1474 838 21 24 839 4102 338 4102 831 5472 838 3104 i 838 3104 838 3104 838 5683 338 310...

Page 120: ...rator w Schmitt T rigger inputs 1F 7438 Buffer and Interface Gate 2F 8 Resistor Network 4F 7438 Buffer and Interface Gate 841 9003 841 9003 841 9004 805 O733 805 0592 801 0406 802 0020 802 0020 805 3011 805 0463 800 0123 802 0074 802 0074 802 0004 805 462 802 0086 848 9001 802 0014 801 0407 805 0462 802 0221 8000038 829 OD07 8000038 ACA8058 ACA8058 ACA8057 AMX4326 AMX3688 AMX3675 AMX3555 AMX3555 A...

Page 121: ... R61 1K WW 5 R62 150 ohms WW 5 R63 10K WW 5 R64 1 K WW 5 R65 750 ohms WW 5 R66 390 ohms WW 5 R67 Not Used R68 IK WW 5 R69 IK WW 5 820 7210 820 7210 820 7175 820 7139 820 7310 820 7139 820 1230 820 1176 820 7239 820 7210 820 7347 820 7222 820 7222 820 1176 820 7182 820 7139 820 1215 820 1176 820 7210 820 7210 820 7230 820 7310 820 7210 820 7130 820 7210 820 7115 820 7210 820 1313 820 1328 824 7115 ...

Page 122: ...8 2N4124 NPN 811 0124 811 0124 811 0124 811 0124 810 0125 811 0124 AMX4178 AMX4178 AMX4178 AMX 41 78 AMX4330 AMX4178 MISCELLANEOUS 16 pin 1C Socket 2 1 6 pin D IP Shunt Socket 5 pin Right Angle Header 14 pin Right Angle Header 2J Staking Pin 13 Resistor ohm vlaue Jumper 4 position PC Mount Housing 2 850 9003 848 9001 851 9054 851 9060 852 9014 829 0000 851 9056 AJ6581 AL0907 AJ6815 AJ6816 AHB9682 ...

Page 123: ... ACC474MGTA ADX114S ACA8059 U1 LM2917N Frequency to Voltage 8050917 AMX4181 Converter RESISTORS R1 20K r 1 4 W 5 8207320 AN0306EEC R2 1M 1 4 W 5 8207510 AN0445EEC R3 IK 1 4 W 5 8207210 AN0196EEC R4 IK Trim Potentiometer 8289210 AP7058 R5 IK 1 4 W 5 8207210 AN0196EEC R6 43 2K 1 4W 1 8201343 AN0576BEC R7 470 ohms 1 4 W 5 8207147 ANQ169EEC R8 470 ohms 1 4W 5 8207147 AN0169EEC R9 18 ohms 1 4 W 5 82070...

Page 124: ...4181 Converter RESISTORS R1 20K 1 4W 5 8207320 AN0306EEC R2 1M 1 4 W 5 8207510 AN0445EEC R3 1K 1 4 W 5 8207210 AN0196EEC R4 1 K Trim Potentiometer 8289210 AP7058 R5 1K 1 4 W 5 8207210 AN0196EEC R6 150K 1 4 W 5 8200415 R7 470 ohm 1 4 W 5 8207147 AN0169EEC R8 1K 1 4 W 5 8207210 AN0196EEC R9 470 ohm 1 4 W 5 8207147 AN0169EEC R10 1K 1 4 W 5 8207210 AN0196EEC R11 1 ohm 1 2 W 5 8217001 AN0022EFC R12 2 2...

Page 125: ...FIGURE 17 ILLUSTRATED PARTS CATALOG EXPLODED VIEW 118 ...

Page 126: ...85 22 Hub Retainer Screw 8852056 AH D 1600 23 Hub Shaft _ 24 Cone Assembly 8852021 ART2740 25 E ring medium cone 8852050 AHE0030 26 Latch Assembly 8852022 ADA0303 27 Foam Cone Lever Pad 8852063 AHB9986 20 Right Hand Guide 8852023 ART2742 30 Crimp Pin tin 8852045 AHB9982 gold 8852046 AHB9983 inside Head Plug 31 Upper Arm Assembly 8852044 ART3002 32 Carriage Shaft 8852065 ART3050 33 Head Carriage As...

Page 127: ... j l l l u 35 uj J 2 HO O z L _ _ UJ UJ I w o I o CO UJ Q CO 120 ...

Page 128: ...go UJ W w u UJ t x UJ I CO o I O CO UJ Q CO Q 121 ...

Page 129: ...MICROFARADS UNLESS OTHERWISE SPECIFIED TACH TACH P21 T 1K R4 1KPOT A VV AVv vWhi 3 3 nh trcr CHARGE PUMP U1 LM2917N C R6 150K MOTOR POWER MOTOR RETURN N MOTOR ON NOTES 1 ALL RESISTORS ARE 1 4 WATT 5 UNLESS OTHERWISE SPECIFIED LINEAR SERVO BOARD FIGURE 19 SERVO BOARD SCHEMATIC 2 ALL CAPACITORS ARE IN MICROFARADS UNLESS OTHERWISE SPECIFIED 122 ...

Page 130: ... In 01 vW j l CO Q CC O CO u_ O o I o CO CC Q CO o CM CC CD 123 ...

Page 131: ...CM 1 LLI LU I W Q DC O CO o o I o GO LU oc a 00 Q 124 ...

Page 132: ... S A FORT WORTH TEXAS 76102 CANADA BARRIE ONTARIO L4M 4W5 TANDY CORPORATION AUSTRALIA BELGIUM U K 280 316 VICTORIA ROAD PARC INDUSTRIEL DE NANINNE BILSTON ROAD WEDNESBURY RYDALMERE NSW 2116 5140 NANINNE WEST MIDLANDS WS10 7JN 8 81 PRINTED IN U S A ...

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