Radio Shack TRS-80 26-3650, Service Manual

Page 1: ... T TRS 80 PC 4 Pocket Computer and Cassette Interface Catalog Number TP9 i I I U C 3 53 G3 X rrn rn ra 3 3 tT CD C3 i I H CUSTOM MANUFACTURED FOR RADIO SHACK A DIVISION OF TANDY CORPORATION ...

Page 2: ...arenthetical addition subtraction multiplication and division with priority sequence judgement function true algebraic logic Trigonometric inverse trigonometric functions angular units degree radian gradient logarithmic exponential functions square root powers conversion to integer deletion of integer portion absolute value symbolization designation of number of effective positions designation of ...

Page 3: ...tandard 26 expandable to 94 maximum 222 memories when optional RAM pack is loaded and exclusive character variable Subroutine 8 levels FOR NEXT loop 4 levels Numerical value 6 levels Calculation elements 12 levels Two lithium batteries CR2032 Maximum 0 02W Main frame only approximately 360 hours continuous use Power is turned off automatically approximately 7 minutes after last operation 9 8mmH X ...

Page 4: ...KEYBOARD RAMI HD61914 77 RAM2 HD61914 EXPANSION RAM MODULE LCD 12 digit dot matrix display A character or a number is displayed in 5X7 dots CPU CMOS VLSI one chip microprocessor unit RAM Stores data and program Each RAM has 1 K bytes 8K bits capacity and contains self control circuit 3 ...

Page 5: ...0864 bits o Built in RAM 1896 bits o Built in display driver o Memory backup function o Clock 400 kHz Internal machine cycle 200 kHz Minimum instruction execute time 10 xS 3 2 CPU Block Diagram Control signals A ROM System Program 7 Instruction Decoder Address Control V Keyboard Signals 4 ...

Page 6: ... kohm external resistance between these terminals clock pulse is inter nally generated 27 72 R15 R7 Out LCD display signals 73 GND In zero volt power source 74 75 CE1 CE2 Out Chip enable signals CE1 selects RAMI at HIGH level while CE2 designates RAM 2 at HIGH level 76 VDD1 In 5 5V input 77 VDD2 Out 5 5V output from the LSI Stays 5 5V at power ON Goes to 0V at power off or APO Auto Power Off 78 79...

Page 7: ...te RAM and contains self control circuits The following shows a memory map of RAM 1 and RAM 2 optional RAM pack RAMI System Memory User s Area RAM 2 000 21F 220 User s Area 7FF 800 FFF Note The above addresses are for when one word is 4 bits _ 6 ...

Page 8: ... SERVICING 5 1 Disassembly Remove two screws from the back Lift and slide down the lower case Remove the battery cover Extract batteries Remove eight screws from the guide plate Remove the guide plate 7 ...

Page 9: ...usual indication Some dots cannot be displayed RUN DEG I i CAUSE 1 RAMI 2 CPU CPU 1 CPU 2 LCD 3 Heat seal B Key Entry LSI s to function CPU Key input operation Displaying RAM 1 Storing entered numbers or characters TROUBLE No entry at al Cursor moves but entered number or character cannot be displayed Only characters can be entered CAUSE t CPU 2 Wiring between CPU and keyboard 1 RAMI 2 CPU 3 Wirin...

Page 10: ...ay be faulty D RAM 2 Optional RAM module 1 Install the RAM module in a PC 4 2 Push the ALL RESET button on the bottom 3 Operate MODE 1 1 and confirm that the remaining program step is 1568 If the display shows the remaining step as 544 a RAM 2 is not functioning b Wiring between CPU and RAM 2 has failed 4 Operate DEFM 190 EXE and confirm the display VAR 216 5 Write the following program 10 FOR I 1...

Page 11: ...s cannot be made the CPU may be faulty 2 Program Execute the following program after pushing the ALL RESET button on the bottom 10 FOR I 1 TO 2 FOR J 1 TO 2 FOR K 1 TO 2 FOR L 1 TO 2 20 NEXT L NEXT K NEXT J NEXT I 30 GOSUB 40 PRINT END END 40 GOSUB 50 50 GOSUB 60 60 GOSUB 70 70 GOSUB 80 80 GOSUB 90 90 GOSUB 100 100 GOSUB 110 110 RETURN RETURN RETURN RETURN RETURN RETURN RETURN RETURN After executi...

Page 12: ... 12345 234 345 SQR 0 SQR 2 SO R 30 SIN 30t 2 30 FOR H 5 TO 4 D D RND 5544 4455 H NEXT H 40 A 1 E A A A A A A A I 50 GOSUB 3 60 RETURN P3 Hon 2 10 X 123 0 H J 0 20 MID 1 3 MID 4 ABC 30 GOTO 4 P4 10 IF l J K L 15 THEN 1 20 IF A B E X 125 THEN 30 25 GOTO ER 30 IF H J ABC THEN 1 40 IF RND C 5 1894 4034 THEN 1 50 IF RND D 2 55000 THEN 1 60 GOTO 5 P5 10 GOTO 20 15 RETURN 20 GOTO 15 P9 10 FOR A 1 TO 201 ...

Page 13: ...tape Load the test program from the cassette tape by the operation LOAD A EXE After loading the Program change the PC 4 to WRITE mode by the operation MODE 1 and confirm that the remaining program step is 789 Operate MODE O RUN mode selection Execute PO Program numberO Confirm the display TEST 1 OK Clear the programs POto P5 Example to clear P2 a SHIFT 2 P2 designation b MODE 1 WRITE mode selectio...

Page 14: ...ing if the result of the comparison is true Causes control to proceed to the next line number if the result of the com parison is false GOSUB GOSUB iinen variable Calls out the subroutine of the desig nated line number for execution After the subroutine is executed control returns to the GOSUB statement by the RETURN statement to proceed to the command following that statement RETURN RETURN Signif...

Page 15: ...degree 4 radian 5 or gradient 6 Format designation SET fEn SET Fn ti J 0 n 9 Designates the number of effective positions or number of decimal positions for the displayed numerical value Character function LEN LEN character variable Calculates the size of the character variable MID MID m n Extracts n characters from the mth character in the exclusive character variable S VAL VAL character variable...

Page 16: ...Correct the designated line number 5 Argument error For a command or function that requires an argument the argument is outside the input range Correct the argument error 6 Variable error Attempt was made to use a memory which has not been expanded Attempt was made to use the same memory for a numerical variable and a character variable at the same time Expand the memory properly Do not use the sa...

Page 17: ... 300BPS For remote control Two AA size dry batteries 0 3W Approx 7 hours 173mmW X 114mmD X 31 5mmH 2 BLOCK DIAGRAM D4 6 VODS Q CE2 s CO c Q E o OP GND 0 c LSI HD43110 77 CRYSTAL OSCILLATOR FILTER CIRCUIT SHAPING CIRCUIT REMOTE CONTROL CIRCUIT D MIC EAR REMOTE 3 CO H a 30 CD 8 Q CD LSI Kansas City standards applied cassette tape interface LSI Transfers serial data by the following frequencies Data ...

Page 18: ...of each terminal of the LSI Pin No Signal Name In Out Function 2 OSC In Clock pulse 32 768Hz input 7 VDD Out 3V output 8 CONT In The LSI functions only when the terminal is HIGH 9 VDD1 In 3V input 10 CE In Chip enable terminal The LSI is designated from PC 4 when the terminal is HIGH 11 SP In Strobe pulse input from PC 4 13 D4 In Out Serial data input output 14 GND In 0V input terminal 17 C3 In Da...

Page 19: ...al oscillator and is shaped by the inverters D y Dr 7 7 4 2 Remote Control Circuit wv wv 1 Q1 4T 6 3V RY ON OFF Q2 REMOTE When signal C1 is HIGH transistors Q1 and Q2 turn on causing relay RY to be switched on so that the REMOTE terminal becomes active 4 3 Shaping Circuit and Filter MIC EAR 18 ...

Page 20: ...put C2 from the LSI is integrated waveform and shaped into an AC waveform waveform by capacitor d and resistor r1 B Input signal from tape recorder is integrated by capacitor c2 and resistors r2 and r3 waveform The waveform is cramped between 3V and OV by diodes d1 and d2 19 ...

Page 21: ...5 SERVICING 5 1 Disassembly 1 Remove six screws from the back 2 Open the lower case 20 ...

Page 22: ...assette recorder with a tape of music Clock pulse Replace crystal oscillator Signal C3 of the LSI Shaping circuit If C3 is normal replace the LSI Remote control impossible Click sound of the relay at saving or loading If click cannot be heard check signal C1 of the LSI If signal C1 is not output from the LSI replace the LSI If C1 is normal remote control circuit may be faulty Check to see if there...

Page 23: ...TV SCHEMATIC DIAGRAM I 26 NAND TC30H00F INVERTER TC30H004F 7Pin VDOI l4Pln GND 22 ...

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Page 25: ...IV PRINTED CIRCUIT BOARD 26 3650 o 26 3651 26 3653 24 ...

Page 26: ...Exploded View 26 3650 ...

Page 27: ...ip RC315B220K J 200Kohm 5 1 8W 27908071 Resistor Chip RC315B65K G 68Kohm 2 1 8W 27908551 Resistor Chip ERJ 8GCSJ225 2 200Kohm 5 1 8W 27909485 Capacitor Chip CM21YV103P15V 0 1 M F 15V 20 71032167 Capacitor Chip C3225C0G1H222K 2 200pF 50V 10 28907407 Capacitor Chip CM21CH102K25V 1 000pF 25V 10 28907415 Resistor Chip ERJ 8GCSK101 IKohm 1 8W 5 27909019 Resistor Carbon Film ERD10TJ333 33Kohm 1 10W 5 26...

Page 28: ... 2 63345174 3 Spring Battery A G272 A33938A 1 63297621 4 Spring Battery B G272 A33939 1 63297630 5 Spring Battery C G272 A33940 1 63297640 6 Plate Battery Insulation G272 A45154 1 63297660 Cushion Battery G1002 A46287 1 63336860 7 Holder Battery G420 A45884 1 63327190 8 Plate Insulation B G420 A45918 2 63339490 Plate Insulation A G420 A45921A 1 63327171 Plate Insulation E G420A A46326 2 63339970 P...

Page 29: ...326980 17 Spring Switch Contact G310 A45208 1 63298310 Spacer Switch G420 A46325 1 63339930 18 Film Common 6420 A21302 1 63327290 19 Spacer G1002 A46286 1 63336870 20 Screw Flat C G321 A33793 3 63282790 21 Spring Ground G1002R A46432 1 63345160 22 Rubber Key Contact B G420 A35390 1 63327030 Key Top Set for PC 4 GX 1002AA 00018003 Case Soft G1002RA A35692 1 Canada USA 63344241 Case Soft G1002TA A35...

Page 30: ... 10 HE705JYB332K 28180152 Capacitor Semiconductor Ceramic 0 047 F 50V 20 SC45F1H473Z 28127511 Resistor Solid 26Mohm 1 8W 20 ERC 18GM2665 27901476 Relay FBR211CD003 M 31206057 Capacitor Electrolytic 22 F 10V 10 28040954 Diode Silicon 1S2075K21 23001021 Resistor Carbon Film 390ohm 1 4W 5 R 25 390 l 26003911 Resistor Carbon Film 2 2Kohm 1 4W 5 R 25 2 2K J 26005710 Resistor Carbon Film 1Kohm 1 4W 5 R ...

Page 31: ...sistor Carbon Film 4 7Kohm 1 4W 5 R 25 4 7K J 26006511 Resistor Carbon Film 100Kohm 1 4W 5 R 25 100K J 26009715 Resistor Carbon Film 120Kohm 1 4W 5 26009910 Case Sub Ass y Upper A35413C 2 63344334 Plate LOGO A36263 2 63344360 Plate Power ON OFF Model Name A45867 2 63344350 Sheet Insulation Aluminum 63345140 Case Upper G426 A1 803B 1 63329912 Case Sub Ass y Lower A21315B 2 63344343 Case Lower G426R...

Page 32: ... Female 126D 019 12N04 35113639 Connector 12Pin Male 126D 019 12P22 35103244 Cord Connection For Cassette PLGW 1596 01 27009237 Cover Battery G426 A21328 1 63329890 Knob Slide Lock Free B G426 A35453 1 63329950 Knob Slide Power ON OFF G426 A35452 1 63329940 Capacitor For Connector G426R A45915 1 63346370 Plate Computer Unit LOCK FREE G426 A45988 1 63329960 Plate Slide LOCK FREE Knob A45987 1 63329...

Page 33: ... G320 A44793 1 63291680 Screw Tapping Flat Head M2 X 4 Black A G324 A33953 3 63316670 Screw Tapping Flat Head M2 X 6 Black C G302 A44793 9 63291620 Case Soft G426RA A35688B 1 USA Canada 63344412 Case Soft G426TA A35897 1 UK Belgium Australia 63352220 Cap For Connector G426 A46150 1 63332410 32 ...

Page 34: ...Discrimination Between CPU and RAMI 10 5 3 Test Program 11 6 PROGRAM COMMAND LIST 13 7 ERROR MESSAGE LIST 15 II CASSETTE INTERFACE 26 3651 1 SPECIFICATIONS 16 2 BLOCK DIAGRAM 16 3 LSI HD431 10 17 4 CIRCUMFERENCE CIRCUITS 4 1 Clock Pulse Generator 18 4 2 Remote Control Circuit 18 4 3 Shaping Circuit and Filter 18 5 SERVICING 5 1 Disassembly 20 5 2 Troubleshooting 21 III CIRCUIT DIAGRAM 1 26 3650 22...