Radio Shack TRS-8O Page 4 Service Manual Download

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Summary of Contents for TRS-8O

Page 1: ...ladleIhaeK ervlce TRS BO DISK VIDEO INTERFACE AND EXPANSION FLOPPY DISK DRIVE UNIT l 1 Catalog Numbers 26 3806 3807 CUSTOM MANUFACTURED FOR RADIO SHACK A DIVISION OF TANDY CORPORATION...

Page 2: ...INTERFACE CIRCUIT 4 6 CRT INTERFACE AND CONTROL CIRCUIT 4 8 FLICKER SUPPRESSING CIRCUIT 4 11 FDD INTERFACE SIGNALS 4 11 FDD CONTROL CIRCUIT 4 13 POWER SUPPLY AND RESET CIRCUIT 4 16 5 TROUBLESHOOTING 5...

Page 3: ...2 5 INPUT SIGNAL LINES CPU TO FDD _ _ C 23 2 6 OUTPUT SIGNAL LINES FDD TO CPU C 29 PART 3 CIRCUIT DlAGRAM_ C 33 PART 4 TROUBLESHOOTING __ __ C 35 4 1 PROCESSING SOFT ERRORS _ _ C 35 4 2 FLOPPY DISK D...

Page 4: ...ck Diagram Receive Mode System BUS Interface Block Diagram Transmit Mode CRT Interface Block Diagram Display Timing Chart 40 Characters Mode Display Timing Chart 80 Characters Mode Waveform of Video S...

Page 5: ...lock Diagram of Drive Select Circuit 0 0 0 Side Select Circuit 0 0 0 0 0 0 Head Positioning Circuit 0 0 0 0 0 0 Timing Chart for the Direction and Step Signal 0 0 0 0 0 Write Circuit and Erase Circuit...

Page 6: ...4 4 2 Signals from the Portable Computer 4 6 4 3 PPI Function Table 4 7 4 4 Function of the Principal Signals _ 4 8 4 5 FDG Function Table 4 13 4 6 Description of the Principal Terminals 4 13 B 1 Sys...

Page 7: ...des instructions for installing an additional disk drive unit Appendix B provides technical information for connector signals Appendix C provides service information on the built in FDD unit General B...

Page 8: ...Drive 0 This is the disk drive unit used for the BASIC SYSTEM diskette Drive Select LED LED lights during access of the diskette CD Optional Disk Cover Remove this cover to install the expansion drive...

Page 9: ...x 25 line display G Home TV Terminal Provides RF output modulated to Channel 3 or Channel 4 of the TV frequency Connect your home TV set to this terminal using the TV cable and switch box supplied Cha...

Page 10: ...Output Level Horizontal Scanning Frequency Vertical Scanning Frequency 120 Volts AC for USA and Canada 220 Volts AC for Belgium 240 Volts AC for UK and Australia 66 Watts S C 40 C 20 to 80 430 x 125 x...

Page 11: ...isconnect the two connectors marked eN1 and CN4 on the main P C Board 2 Remove the four screws B 3 Take out the main P C Board Be careful not to damage the connectors and switch inside on the rear pan...

Page 12: ...cket by sliding them toward the rear of the unit 4 Remove the screws E two each on the left and right supporting brackets securing the floppy disk drive unit tr D Figure 2 3 Disk Drive Removal Front P...

Page 13: ...d not be used to clean the magnetic recording head Use of cleaning solvents other than 91 Isopropyl alcohol may damage the head Extreme care must be exercised to prevent the head from being damaged do...

Page 14: ...C voltmeter across pin 2 of CN4 Ground and pin 3 of CN4 5V on the Main PCB 2 Adjust VR 101 on the Power Supply PCB to read 5V 0 1 V 0 1 V on the DC voltmeter DC voltmeter OJ 0 INPUT 4 5 J4 U 3 ad US F...

Page 15: ...control program from track 1 of the system diskette actual memory size used is 1K bytes 4K bytes of RAM to store the control program read e 4K bytes of VRAM Video RAM to display characters on the CRT...

Page 16: ...the select signal and data BUS for the PPI CRTC and FDC Interrupt Two term inals INT I nterrupt Request and i fMl Non Maskable Interrupt accept interrupts By writing data into the PPI via the Portable...

Page 17: ...ARAM C Y6 A14 2 8 Y7 7 CRAM A13 1 AGND V 6 c Figure 4 3 Address Decoding and BANK Selection Circuit Memory Map The DisklVideo Interface uses two 4K byte P ROMs and four 2K byte Static RAMs At power on...

Page 18: ...CRTC for Write 1FH 03H Status Register of CRTe for Read 20H S1 S 20H I Bit Read Write 0 PPI PBO Select 80 characters mode 1 PB1 Select Bank 1 2 PB2 Not Used 3 PB3 Not Used 4 PB4 Select Drive 0 5 VSRE...

Page 19: ...actor of character display is DCLK DCLK is a timing signal which shows 1 dot on the CRT Every eight DCLK outputs one lOAD signal lOAD is a timing signal which displays one character on the CRT There a...

Page 20: ...isk Video Interlace If you are going to transmit data from TRS 8D Portable Computer to the Disk Video Interface the Portable Computer checks O i3F Output Buffer Full first If this signal is L the Port...

Page 21: ...BF I I Rottiei I I _J L f L_ I i ty i I 1 IORD STS Figure 4 7 System BUS Interface Block Diagram Transmit Mode 3 Data Modes There are four types of data transaction modes to transfer data between the...

Page 22: ...which M5 composes VSYNG vertical sync signal and HSYNC hori zontal sync signal generated in CATe is also input then T1 generates composite video signal for CRT composing these two input signals When u...

Page 23: ...O MM fAl0 74l 166 MAW MAlO Octol Chof eM 2K RAM IC RAM Latch GQ O ator eM M co co GO M co A VideQ HSY C AYNC SOUT Si n 1 I AW 07 m 0 m Generator SHIFT Ll E5 AO A2 l OAD j M t AD c6 A01 HSytc VSYNC VnA...

Page 24: ...ng Chart 80 Characters Mode r I I 12 8ms 192pS Vertical Sync Period 1 1 1 m S 1 16 64mS I Frame Period Vertical Sync Pulse Width 1 Display ON ro __ l Di PlayOFF rr GNO C 0 o 0 5 S Horizontal Sync L 40...

Page 25: ...r FDD 1 DRIVEO and DRIVE1 to Fool When either of the two input lines becomes L only the L signal drive can respond to the input lines gate the output lines and turn the drive select LED on DRIVE SELEC...

Page 26: ...l 7 IP from FDOl The L signal is provided by the drive everyone rotation of the diskette indica ting the beginning of the track 8 ROATA from FOOl This line provides a clock data pulse which is convert...

Page 27: ...Model II Technical Reference Manual since this LSI is functionally identical to the 1791 used in the FDC Printer Interface Board of the Model II except that the data BUS is true as opposed to inverted...

Page 28: ...drive shall be low for each recorded flux transition WG Write gate Output This signal becomes active before disk write operation occurs f WD Write data Output This signal consists of data bits and clo...

Page 29: ...RLY A 0 0 M Q 3 LATE M4 1 2 Q 1 1 ILATE Mode L5 Figure 4 15 Pre Compensation Circuit 4 Wait Control Circuit As shown in the figure below this circuit controls read write data transaction between the C...

Page 30: ...This circuit generates 5 volt and 12 volt power 12 volt is supplied to the FDD and RF modulator and 5 volt is supplied to all of the les except M41 and M44 in the system BUS interface circuit The RESE...

Page 31: ...tion and provides remedial instructions After completing any repairs you should re check each functional item according to the CHECK LIST You can make use of the CHECK LIST even if the location and co...

Page 32: ...2 Is 15 25V applied to the cathode of 0101 If not check power transformer and Dl01 D104 3 Check output voltages al vee 5V O 25V If not check ZD101 VR 101 R107 Rl09 R11 0 ClOG e1C Cl 08 ClOg LT02 L103...

Page 33: ...51 C52 and Xl b Pin 11 of M47 8 MHz If not check M47 c Pin 6 of M42 4 MHz If not check M 14 and M27 d Pin 24 of M26 1 MHz If not check M27 and M32 2 Check all ICs Try to replace the FDD unit END 2 Fan...

Page 34: ...doesn t load the control program 9 j Replace the System Diskette _ 1 r Check the cable from Power Supply PCB to Main PCB the cable from Power Supply PCB to FDD and the cable I from Main PCB to FDD _...

Page 35: ...signals __ I Check to see if the clamp lever of FDD is turned downward Try to replace the FDD I 5 System doesn t load the DISK BASIC __ J j Replace the System Diskette Ckthe conn tionbet ee m RS 80Di...

Page 36: ...4 and C301 END 6 FDD doesn t function If system doesn t read the contents of the diskette refer to 4 System doesn t load the control program or 5 System doesn t load the DISK BASIC If system doesn t s...

Page 37: ...orm of LOAD signal 1 MHz at 40 characters mode 2 MHz at 80 characters mode If not check M29 M30 M32 M33 and C78 _ Check the CRT interface and control circuit 1 Check the frequency and waveform of HSYN...

Page 38: ...iskNideo Interface to home TV set correct 4 Is RF output eha nne the sa me as the eha nneIof TV set 5 Is the switch on the Switch box unit positioned to COMPUTER side L _ Check the timing generator ci...

Page 39: ...program 10 CLEAR 1000 AS B 20 FOR 1 32 TO 159 30 AS A CHRS I 40 NEXT I 50 T O S O GOSUB 500 60 S 1 GQSUB 500 70 T 39 S 0 G05UB 500 80 5 1 GOSUB 500 90 T O 5 0 GOSUB 1000 100 8 1 GOSUB 1000 110 T 39 S...

Page 40: ...rogram 10 SCREEN1 A 40 20 WIDTH A 30 FOR 1 32 TO 255 35 IF 1 127 THEN50 40 PRINTCHR I 50 NEXT I 60 PRINT PRINT IF THE DISPLAY IS OK PRESS ENTER 70 A INKEY IF A THEN GOTO 70 80 IF A 40 THEN A 80 GOTQ 2...

Page 41: ...6 Exploded View and Parts List 15 CN302 1 1 1 Figure 6 1 Ex 6...

Page 42: ...APS I...

Page 43: ...Capacitor Tantalum 1 uF 10V 20 CSKCOlOMDC C27 Capacitor Ceramic 0 047 uF 25V1 10 CSF1 E473KY C28 Capacitor Ceramic O o47 uF 25V1 1 0 CSF1 E473KY C29 Capacitor Ceramic 0 lpF 12V 20 CSF1S104MY C30 Capa...

Page 44: ...C68 Capacitor Ceramic 470pF 50V 1 0 CKFB471 KBM C69 Capacitor Ceramic 1OOOpF 50V 10 CKFB102KBT C70 j j j C71 C72 Capacitor Ceramic 1000pF 50V lO9 0 CKFB102KBT C73 Capacitor Ceramic 470pF 50V 10 CKFB4...

Page 45: ...TTL Inverter I C TTL OR Gate I c TTL AND Gate I c TTL Flip Flop I C TTL Buffer HD74LS74AP or SN74LS74AN or M74LS74AP or MB74LS74A HD74LS08P or SN74LSQ8N or M74LS08P or MB74LS08 HD74LS32P or SN74LS32N...

Page 46: ...MB74LS32 HD74LS138P or SN74LS138N or M74LS138P or MB74LS138 HD74LS04P or SN74LS04N or M74LS32P or MB74LS04 HD74LS163P HD74LS32P or SN74LS32N or M74LS32P or MB74LS32 HN462732G For USA and Canada For UK...

Page 47: ...stralia M41 I C C MOS Buffer TC40H365P MX 5972 OQ040365AT M42 LC N MOS CPU pPD780C l or MX 5956 OONOO780AA LH0080A or OONOO80AA3 MK3880 4 or QQN03880BZ Z 80A I OON80ACPUZ M43 I e TTL DRVR DCVR HD74LS2...

Page 48: ...l 4W 5 10K ohm 1 4W 5 470 ohm l 4W 5 1 2K ohm 1 4W 5 4 7K ohm l 4W 5 330 ohm l 4W 5 4 7K ohm 1 4W 5 1K ohm 1I4W 5 1K ohm l 4W 5 lK ohm l 4W 5 330ohm l 4W 5 lK ohm l 4W 5 33K ohm l 4W 5 1K ohm l 4W 5 1...

Page 49: ...R53 Resistor Carbon 33K ohm l 4W 5 RD25PJ333X R54 Resistor Carbon 33K ohm l 4W 5 RD25PJ333X J RF MODULATOR I odulator I RFl For USA and Canada AX 9440 ZUVOOOO203 For UK and Belgium ZUVOOO3601 J j For...

Page 50: ...35V 20 CEAF221A3N Gl11 Capacitor Ceramic OJ IF SOV1 80 20 CBF1H104ZT w __ w ___ CONNECTORS CNlOl Jack Junction to Power Transformer AJ 7530 YJF02S039Z CN102 Jack JunctIon to FDD 0 AJ 7531 YJF04S038Z...

Page 51: ...5 56ohm l 4W 5 1K ohm 1 4W 5 10ohm 1W 5 N 0344CEC RD25PG560Z RD25PJ102X RD25PJ103X RD25PG5102 RD25PG3302 RD25PJ470X RD25PJ470X RD25PJ271X RD25PJ102X RD25PJ560X RD25PJ102X RX1BNJ100B _____JQQZHZ2CLX I...

Page 52: ...ok 2 2 M H s s n A 1 LF220KE04Y POWER SUPPL Y ASSEMBLY 1 ACAC196ULA ACAC202BSA ACAC203EEA ACAC204ASA ACZZ156ULA APLX128BAA FJ0060N03D SC010203VQ SC020212AZ TPF66V002P TPG66E004P YHF1S3009U YHF1S2005Z...

Page 53: ...r Supply MB877SZ001 8A Screw Sems Machine M3 x 6 S ZnCr AHD 2759 BSPN3006NZ 8 5 Screw Cup Head Machine M3 x 6 S ZnCr BSP43006NZ 8 6 Screw Cup Head Machine M4 x 6 S ZnCr AHD 2756 BSP44006NZ B 10 Screw...

Page 54: ...4 1002 3 Foot Rubber AF 0369 VM283SBOOl 4 Case Top Ivory AZ 7101 MB887SMOO8 5 Support Floppy Disk Right ML772SZ001 6 Support Floppy Disk Left i ML772SZ002 7 Panel Back Ivory For USA and Canada AZ 7102...

Page 55: ...d Canada ZVDM001302 for Model 100 For UK Belgium and Australia ZVDMOO1303 Cover ROM for Model 100 VS667SBOO5 CRT Cable For USA and Canada ACPP018GEA For UK Belgium and Australia ACPP020GEA Switch Box...

Page 56: ...7 P C Board Views and Schematic Diagra NOTE Following two drawings are applicable for USA and Canada Versi Figure 7 1 Main...

Page 57: ...agram Canada Version re 7 1 Main P C Board Top View 7 1...

Page 58: ...Figure 7 2 Main F...

Page 59: ...lin P C Board Bottom View 7 2 o...

Page 60: ...NOTE Following two drawings are applicable for UK Belgium and Australia Vet Figure 7 3 Main P C Board 7...

Page 61: ...Australia Version c Board Revised Top View 7 3...

Page 62: ...Figure 7 4 Mai...

Page 63: ...Main P C Board Revised 7 4 Bottom View i o...

Page 64: ...I PC Board Power Supp y Top View o o c J d Top View P C Boar Supply 5 Power Figure 7 7...

Page 65: ...Botton View I b odt 2 o x o it w N j 0 I i 1tt 1 0 I 1 01 1 5 1 RL 1 1 m Figure 7 6 Power Su I pp Y P C Board Bottom View 7 5...

Page 66: ..._ uk c T F w I LI I 1 I i I _ 1 AA 1 I jI M_ll 00 i i 0 1 0 I _ 0 I l w o m o g...

Page 67: ...co L llr tw I L Vc o_ S I T I r t f r 0 f L it M 0 CO L G 0 1_ j 0 E f 1 I T i J MAIN PCB UNIT 1 L 33CH 1 co 7 6...

Page 68: ...plug marked DS1 If not remove the socket from the plug and reinsert it correctly Figure A t Preparation on p e B of FDD Installation of the additional disk drive is as follows 1 Remove the optional d...

Page 69: ...the power supply cables ACN 5 to the connector on the disk drive and connect the FDsignal cables FD ll These cables are already prepared inside the unit Power Supply Cable ACN 5 Figure A 3 Cable Conne...

Page 70: ...ddress signal bit 14 GND Logic ground GND Logic ground WR Write enable signal RO Read enable signal ScjJ Status signal 10 M 1 0 or Memory signal S 1 Status 1 signal ALE Address latch enable signal Yrf...

Page 71: ...A Canada Austral ia Pin Jack for CRT Monitor Pin Jack for Home TV for UK Belgium Pin Jack for CRT Monitor Pin Jack for Home TV 4 3 Channel Select Switch Channel 2 and 1 for Australia version Figure B...

Page 72: ...or cables Head Step Motor DO Motor Zero Track Sensor To install the P C Board 1 Attach the connector cables to the P C Board Make sure that the connector cables are properly routed 2 Tighten the three...

Page 73: ...ing the clamp lever and pull out the clamp lever from the shaft 3 Remove the four set screws e retaining clamp base BK 4 Pull out the clamp lever shaft by removing the E ring e and clamp lever spring...

Page 74: ...g to section 1 1 2 page C 2 3 Remove the two screws connecting the belt supporter to carrier 4 Remove the head cable 5 Remove the set screws C and l l cif shaft holders OUT and IN and remove the shaft...

Page 75: ...emove carrier BK from the base by referring to section 1 1 3 page C 3 2 Remove the screws 1 positioning and retaining pulse motor K 3 Remove the set screws of the belt supporter 41 Remove the pulley s...

Page 76: ...Motor K Removal 1 Remove the P C board by referring to section 1 1 1 page C l 2 Remove clamp base BK by referring to section 1 1 2 page C 2 3 Remove the three set screws iF holding the spindle 4 Foll...

Page 77: ...1 Remove the P C board by referring to section 1 1 1 page C l 2 Remove the positioning set screw of interrupter AK 3 Remove the interrupter 4 Temporarily tighten the positioning s t screw when mounti...

Page 78: ...loosening the socket screw c Use an alignment diskette The alignment diskette usually stores the index burst signal on two tracks the outer track and inner track d Connect the CH 1 probe of the oscil...

Page 79: ...nually turn the pulley until the mounting screw tr faces downward as shown in the right figUl e below Caution Be sure to wear gloves when touching the steel belt H M2 6x4 Figure C 8 Winding the Steel...

Page 80: ...the right and left holes in the steel belt and mount the pulse motor K on the jig with the mounting screws fQI 2 pes iP SMW 4x 10 Horizontal Direction Figure C 10 Mounting the Pulse Motor K 5 Turn th...

Page 81: ...when the belt supporter is sllded horizontally to the right or left Steel Belt I i 121 I I I C D 8 D 00 00 00 00 til Belt Supporter Figure C 12 Confirmation of the Belt Gaps 8 Manually turn the pulley...

Page 82: ...of the index signal of pin 4 of Tp 2 The waveform should be stationary 4 Connect CH1 to pin 3 of TP 1 and CH2 to pin 4 of TP 1 and GND to pin 2 of TP l or pin 5 of TP 2 5 A temperature and humidity co...

Page 83: ...nal Connect other channeis 1 and 2 to pin 3 of TP l and pin 4 of TP l as the ground for each probe Set to ADD mode set either pin 3 or 4 of Tp l to INVERT and set the time base at 20 ms vis Measure th...

Page 84: ...f TP lls connected to GND The dse of the STEP signal em ltted from pin 1 of TP 2 is synchronized 3 Set the oscilloscope as following condition Mode set to chop Volts set to 2VIdiv Time set to 1 mS div...

Page 85: ...ntil the below waveforms are obtained Atter adjustment tighten the fixing screw Outer Direction Inner Direction 8A AD DC 2 3mS Max C8 L 21_m_s_M_iO_ _ r 2 3mS Max I CH 2 r AD DC SA AD SA 6mS CH 1 Trac...

Page 86: ...ightly dampen and cotton swab with isopropyl alcohol 2 Part the load arm from the head without touching the load button 3 Softly wipe the head with the dampened part of the cotton swab 4 After the alc...

Page 87: ...sity compaction of the unit powersaving and improved reliability 2 2 Block Diagram Index Write Protect I i iJ Il Drive Select 0 DR IV EO ii Drive Select 1 Active Lamp DRIVE1 I 1 Index I y J A I r I TJ...

Page 88: ...0 Drive Select 3 0 0 lndex Step I Position Control Directibn L L o g i _ J Stepper Motor Track OO Track 00 Logic Track 00 Sensor Write Protect Wri te Protect Logic Write Protect Sensor Write Gate I R...

Page 89: ...the flexible disk drive hereinafter referred to as FOD The package is compact and operated from a single 5V supply All the pins are TIL compatible This LSI mainly controls the logic system Pin Config...

Page 90: ...o II TRKOO 4 7 _ _r Sensor 5V I Pulse Motor 8 Q s Voltage Select ARC 5V IndexPulseG 9 j t B Q ARQ 5V 5V DSQI f o J Pre Ready TRQ Motor On d I t Y f I Int Reset 5V 5V Write Gate V r V V B Q o So Erase...

Page 91: ...ction 16 K3 Side One Select 18 vee 5V 20 EX tal i 22 X tal Terminals for External Crystal _ 24 RESET Reset 26 00 Pulse Motor Phase A 28 01 Pulse Motor Phase B 29 02 Pulse Motor Phase C 31 03 Pulse Mot...

Page 92: ...Floppy Disk read processing is performed by one IC The output can be directly connected to a TIL device Pin Configuration lVcc2 1Amp 15 Outputs JDifferentiator Components Vcc1 GND Offset L Decoupling...

Page 93: ...4 Select 2 Sensor Figure C 25 Block Diagram of Drive Select Circuit The drive select circuit and indicator LED on circuit are configured as shown above When one of these four signal lines drive select...

Page 94: ...sitioning circuit is configured as shown above This circuit is used to move the head using step pulses after the head stepping direction inner or outer direction is determined by the Direction signal...

Page 95: ...s made operable However writing will not occur when the WRITE PROTECT output signal line is low in a write disable state or the corresponding FDD is not selected by the DR IVE SELECT signal line When...

Page 96: ...ut signal becomes a rectangular signal that is inverted by this WRITE DATA pulse In other words the write amplifier inverts the polarity of the head current through this signal to cause the magnetic f...

Page 97: ...r the information track width are efficiently secured by the broad width read write head thus securing the SIN ratio and improving the track density Previous Data Read Write Head Media Running Directi...

Page 98: ...GND 1 Figure C 33 Motor ON Circuit A spindle motor drive signal appears on this input signal line When the input signal is low the spindle motor turns Conversely when the signal is high the motor stop...

Page 99: ...he index hole in the disk this output signal line goes low indicating the beginning of a track The waveform of TP2 4 pin while the media is turning is shown below To in JnL_ 3ms Nom 200mS Figure C 35...

Page 100: ...k 00 causing the photo transistor to turn off and pin 40 of IG6 to go low When the stepping motor reaches phase AD within the range of Track 00 IG6 outputs a low level on pin 32 and the external outpu...

Page 101: ...ng to the disk Conversely when the high signal is output the write enable state is assumed 2 6R4 Read Amplifier Circuit TPl 3 4 TP2 3 Write Head Differ Low Pulse Read Pass Shape V entiator o V Data Fi...

Page 102: ...Low Pass Filter Output TP3 Low Pass Filter Output TP4 Comparator Output Pulse Shaping Output READ DATA TP1 TP2 GND Figure C 40 Timing Chart for Read Amplifier Circuit C 32...

Page 103: ...rcuit Drawing II OQ rp2 O O q b 0 Ie tO IT 1 6 1 0 I G 1 G 5 0 1 T I 12V OC N C Rf URN z RETURN 5V OC NON US of CN4 ReqUIC 10 bo Opened 01 Connoc io to Connector Nc Indica NON Coo olloo N te 2 Note l...

Page 104: ...T i J 4 Q w i G I Fl o n r5 _ I f S _ c Jc S 1 9 L 8 f ii 0 i i S m J 1 5 J Ii J n w t c_ rw l IHi rh Ie T j_ _ 1i B2 1 1H i 5 JNI _N lc n t JH lllf j1 e I Q II I J 0 1 1 1 I a l t 1 _ _ L 0O _ is l...

Page 105: ...ck 00 and make sure that the head is at track 00 3 Move the head to the error occurred track 4 Repeat step Pl 5 Errors which cannot be corrected by repeating the above steps are unrecoverable errors 4...

Page 106: ...eshooting later 1 If the Active lamp will not light and the unit does not operate at all check the DC Power Supply 2 If the Active lamp lights but an operating sound is not heard inside the unit proce...

Page 107: ...lock the door Insert a work disk in Drive 1 and lock the door Select the drive and turn on the hub motor to restore the head to Track 00 I Does No the Active lamp I Check the power unit light y Is th...

Page 108: ...rom Drive 0 and replace the diskette of Drive 0 with the Diskette used by the user Repeat a read test on TROO thru TR39 on Drive O Check the compatibility Do errors occur frequently No J 1 On Drive 1...

Page 109: ...3 outputs a pulse signal No Is the set Yes screw of the DO motor loose Retighten the set screw Replace the drive PCB No I there a media slip y 1_ Placethe clamp INO I Replace IC12 Yes Replace or repai...

Page 110: ...norma Turn off the power switch and move the carrier by hand in both directions Is the carrier movement smooth Yes No No No No No A The interface cable of the host computer is defective Check the DC p...

Page 111: ...4 on eN B at high No level Is pin4 on CN 8 at high level before the carrier touches the OstoPP Adjust the position of the interrupter No output generated on the interface connector The interface or ca...

Page 112: ...B high or low step pulse outputted at pin 5 of lC3 Are the waveforms of pins 4 7 of IC12 normal IC12 is defective No No C 42 lC3 is defective IC6 is defective...

Page 113: ...Is pin 28 y We pm j 4 IOW Check the Notch level I of media No Is any of No the DS signal pin 6 10 12or14 al low level y y Is short No Connect the short in on SWl correctly pin to the OS selected signa...

Page 114: ...unit pin 1 on RA3 at O 7V 1 yO Does the level of 06 become H No and L on and off alter nately with the level of Q7 No R ePlaCeOl Ql or 02 Will pin 1 and 4 an RA4 turn high and low Check with oscillo s...

Page 115: ...a differentia I waveform appear at pins 3 and 4 of TPl Does a read waveform appear at pin 10 of ICl No ICl or head is defective No I ICl is defe_ _ti_W_ _ Does a read waveform appear at pin 8 of IC13...

Page 116: ...1 MAIN UNIT M4 52 5M2 c Figure C 43 Exploded View of Main Unit 52 A M2 SMWl tI Ql 01 tI Ql Cii r eo...

Page 117: ...CLAMP BASE BK CARRIER A BK M26 Q I M23 El M18 El M20 BK and Carrier A BK p Base oded View of Clam 44 Expl Figure C M17 M16 n 1 00...

Page 118: ...n PULSE MOTOR BK 8M3 M30 Figure C 45 Exploded View of Pulse Motor BK M27...

Page 119: ...Figure e 46 p e Board C 50...

Page 120: ...C16 Capacitor Electrolytic 10pF 16V 75 10 EBBOO 53800 C17 Capacitor Electrolytlc 47pF 16V 75 10 EBBOO 34800 C18 XL Cerarock Capacitor KMFC1001S EKHOO 04600 C19 Capacitor Ceramic 1OOOpF 50V 1 0 EBJTO...

Page 121: ...1 EACOO 09900 INTEGRATED CIRCUITS i 1 IC1 I C Disk Read Amplifier HA16631 P EASOO 12700 IC2 I C TTL NAND Gate SN75452 or EAGOO 05000 HD75452 EAGOO 05000 IC3 I C TTL Flip Flop SN74LS74A or EAGOO 12700...

Page 122: ...n Resistor Carbon Not used Resistor Carbon Resistor Metal Oxide Film Resistor Carbon Resistor Carbon Resistor Metal Oxide Film Not used Resistor Carbon Resistor Carbon Resistor Carbon Resistor Carbon...

Page 123: ...istor Array 4 7K x 4 1 8W 5 10 I ECMOO 00300 RA8 I RA9 RAlO Resistor Array 4 7K x 6 1 8W 5 10 I ECMOO 09800 t I TRANSISTORS r Ql Transistor NPN 2SC2021 Silicon NO Rank EAAOO 18900 Q2 Transistor NPN 2S...

Page 124: ...0501 SMW2 Bolt M2 6 x 4 CFA45 61001 M36 Stopper Belt CFA20 63301 M33 Clamp Cable CFA20 63401 5M3 Screw Pan Head Sems M2 6 x 4 CFA45 62301 N1 Nut Hexagonal M3 SNC030018A2 SPWl Washer 2 8x5xO 5 SWA02805...

Page 125: ...Part 6 Special Maintenance Tools 1 Belt Tensioning Jig CFABK 60801 Refer to Mechanical Explanation on Page CoB B o B Figure C 47 Special Maintenance Tool C 57...

Page 126: ...H TEXAS 76102 CANADA BARRIE ONTARIO L4M 4W5 TANDY CORPORATION __ AU_S_TR_ALlA_____ BELGIUM U K _ 91 KURRAJONG AVENUE PARe INOUSTRIEL DE NANINNE BllSTON ROAD WEDNESBURY MOUNT DRUITT N S W 2770 5140 NAN...

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