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Tandy 1000 TL General Maintenance

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Tandy 1000 TL2 (Radio Shack catalogue RSC-21, 1990)
A Tandy 1000 TL/2 from Radio Shack's 1990 catalogue.

Routine care of the Tandy 1000 TL, Tandy 1000 TL/2 and Tandy 1000 TL/3 covers the power supply, the clock battery, the floppy drives, the TL/2 and TL/3 hard disk interface, memory and processor options, and the EEPROM settings. Tandy's technical reference manual for the TL (25-1517) could not be obtained, so the notes below draw on Radio Shack's catalogues, the Tandy 1000 FAQ, Tandy's 1995 parts list for the TL/3 and owners' reports.[1] Wikipedia and the FAQ treat the TL family's video, sound and EEPROM setup as shared with the SL family.[2][3] Tandy 1000 SL General Maintenance covers the SL/2 owner's manual procedures for the case, jumpers and options.

[4][5]

Model differences

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Item TL TL/2 TL/3
Processor 80286, 8/4 MHz 80286, 8/4 MHz 80286, 10 MHz
Hard disk Card or controller in a slot Built-in XT IDE (SmartDrive) Built-in XT IDE (SmartDrive)
Floppy controller Low density only Low density only Accepts 1.44 MB and 1.2 MB drives
Slots Five Four or five (sources differ) Four
Memory sockets for 640-768 KB U36-U39, 120 ns Next to the other RAM, 120 ns U4-U7, 100 ns
Printer port Card edge Card edge 25-pin, bidirectional option
Mouse port None None PS/2-style connector
Catalogue number 25-1601 25-1602 25-1603

Sources: Radio Shack catalogues and the Tandy 1000 FAQ.[4][6][7][8]

Power supply

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All three models have a 67 W supply; the TL/3's is Tandy part TA0455.[4][7][9] No voltage limits or schematic for the TL supplies could be found. With the machine running, check for +5 V on the red wire and +12 V on the yellow wire of a drive power connector, and inspect the supply for leaking or bulging electrolytic capacitors.[10] The TL/3 parts list includes a 680 µF 200 V capacitor (C6) and two fuse ratings listed as F1, 1 A 125 V and 3 A 250 V fast-blow, but does not say which board each sits on.[9]

Clock battery

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The TL series has a built-in clock powered by a removable 3 V CR2032 coin cell.[3] On the TL/3 the cell sits in holder J3.[9] Replace a flat cell with another CR2032. The battery runs only the clock: the setup settings are in the EEPROM and are not lost when the battery is removed.[11]

Floppy drives

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  • The TL family's 3.5-inch drives are Tandy-style drives that take power through the data cable, on pins 3, 5, 7, 9 and 11 (+5 V) and 29, 31 and 33 (+12 V). Replace one only with another Tandy-style drive, or modify the cable as the FAQ describes; a standard drive on the unmodified cable can damage the drive and the computer.[12]
  • The FAQ lists Sony MP-F11W-71 and MP-F11W-72 among suitable low-density drives, and one owner's TL has a Sony MP-F11W-70D.[12][13] That drive has two electrolytic capacitors, which the owner replaced during a repair.[13]
  • The cable is straight, not twisted; each drive's select jumper sets A: or B:.[12]
  • The second 3.5-inch bay in the TL has only part of a shelf. One owner thinks Radio Shack's drive kit came with a bracket to support the drive; another suggests removing the shared bracket, fitting the drive and refitting the bracket, or securing the drive by its left-hand screw holes.[14]
  • After a DOS upgrade, a 720 KB drive may format at 360 KB; add DRIVPARM=/D:0 /F:2 /H:2 /S:9 /T:80 to CONFIG.SYS for drive A:.[15]

General drive cleaning is covered on Floppy Drive Repair.

Hard disks

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  • TL: no built-in interface. Most 8-bit hard disk controllers work.[16]
  • TL/2 and TL/3: the built-in interface takes XT IDE drives only, up to 40 MB, one drive. Do not use Tandy DOS's HSECT or AUTOFMT on them. For a larger drive, fit an AT IDE or SCSI controller and set its ROM to CC00h or CE00h. MFM and RLL controllers do not work in the TL/2; only Seagate ones work in the TL/3.[16]
  • An XT-CF CompactFlash adapter has been used in a TL/2 with its offset BIOS at C800h and port 300h.[17]
  • To boot from a hard disk, set the boot device to DISK with MS-DOS as the start-up program.[16]

Memory and processor

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  • Fit four 64K x 4 DRAMs to go from 640 KB to 768 KB (see the table above). The extra memory goes to video, so DOS gains only part of it.[18]
  • The 80287 socket takes an 80287-8, which Radio Shack sold for the TL; an owner reports an 80287XL working in a TL/2.[19][20]
  • 386 and 486 daughterboards fit the TL and TL/2, but not the TL/3.[21]
  • Expansion cards must be no longer than 10.5 inches.[3]

EEPROM and setup

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Settings live in a serial EEPROM and are changed with the model's own setup program (SETUPTL on the TL). SETUPTL /A gives access to more settings, including the amount of video memory; /B edits the raw EEPROM bits; /F restores the factory defaults. The FAQ warns that /A and /B can leave the machine unbootable.[22] It also warns that DOS 5 or 6 can scramble the EEPROM on Tandy 1000s with DOS in ROM.[23] On the TL/3, the mouse port may need enabling in the setup program.[24]

Keyboard and printer

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  • The TL and TL/2 take an XT keyboard with a 5-pin DIN plug; the FAQ thinks the TL/3 takes an XT keyboard with a PS/2 plug.[25]
  • The TL and TL/2 printer ports are card edges and need a Tandy 1000 printer cable; the TL/3 has a standard 25-pin port.[26]

Maintenance checklist

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  1. Check the rating label before connecting the mains.
  2. Unplug the machine before removing the cover.
  3. Remove dust from the supply, fan and drives.
  4. Inspect the supply and main board for leaking electrolytics.
  5. Replace a flat CR2032 clock cell.
  6. Clean the floppy heads and check the drive select jumpers.
  7. Note the setup program's settings before changing DOS versions.
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References

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  1. ↑ Radio Shack, computer catalogue RSC-20 (1989), p. 27, technical reference manuals, page scan at RadioShackCatalogs.com (retrieved 2026-10-22).
  2. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.B.5.
  3. ↑ 3.0 3.1 3.2 "Tandy 1000", Wikipedia (retrieved 2026-10-21). Sections "Tandy 1000 SL and TL series" and "1000 TL, TL/2 and TL/3".
  4. ↑ 4.0 4.1 4.2 Radio Shack, computer catalogue RSC-20 (1989), p. 18, Tandy 1000 TL specifications, page scan at RadioShackCatalogs.com (retrieved 2026-10-22).
  5. ↑ Tandy Australia, computer catalogue no. 293 (1990-91), p. 3, Tandy 1000 TL/2 specifications, page scan at RadioShackCatalogs.com (retrieved 2026-10-22).
  6. ↑ Radio Shack, computer catalogue RSC-21 (1990), p. 10, Tandy 1000 TL/2 specifications, page scan at RadioShackCatalogs.com (retrieved 2026-10-22).
  7. ↑ 7.0 7.1 Radio Shack, computer catalogue RSC-22A (1991), p. 7, "Home office and family PCs", page scan at RadioShackCatalogs.com (retrieved 2026-10-22).
  8. ↑ Jeff Hayes, "Tandy 1000-series FAQ", version 2.52, 25 October 2005, TVDog's Tandy 1000 archive (retrieved 2026-10-21). Sections II.A.1, II.C.1, II.D.1, II.G.5 and II.H.2.
  9. ↑ 9.0 9.1 9.2 Tandy National Parts, bill of materials 250-1603 "Tandy 1000 TL-3", January 1995, 25-1603.txt, TVDog's Tandy 1000 archive (retrieved 2026-10-21).
  10. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.C.3, drive power cable colours.
  11. ↑ Hayes, "Tandy 1000-series FAQ" (2005), sections II.K.8 and III.E.1.
  12. ↑ 12.0 12.1 12.2 Hayes, "Tandy 1000-series FAQ" (2005), sections II.C.2 and II.C.5.
  13. ↑ 13.0 13.1 "Disk change not working on Tandy 1000TL floppy drive", Vintage Computer Federation forum, January 2026, thread. Post by jamonyorke, 21 January 2026.
  14. ↑ "Tandy 1000TL second 3.5", Vintage Computer Federation forum, May 2020, thread. Posts by Smack2k, Quagmire and vwestlife, 1 May 2020.
  15. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.C.6.
  16. ↑ 16.0 16.1 16.2 Hayes, "Tandy 1000-series FAQ" (2005), sections II.D.1 to II.D.3.
  17. ↑ "Tandy 1000 TL/2 XT-CF and EMS notes", Vintage Computer Federation forum, August 2025, thread. Post by mhenry1762, 23 August 2025.
  18. ↑ Hayes, "Tandy 1000-series FAQ" (2005), sections II.A.1 to II.A.3.
  19. ↑ Radio Shack, computer catalogue RSC-21 (1990), p. 17, "Intel math coprocessors", page scan at RadioShackCatalogs.com (retrieved 2026-10-22).
  20. ↑ "Compatible 287 math co-processor for a Tandy 1000TL", Vintage Computer Federation forum, August 2021, thread. Post by jasa1063, 17 August 2021.
  21. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.F.1.
  22. ↑ Hayes, "Tandy 1000-series FAQ" (2005), sections III.F.1 and III.F.2.
  23. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section III.A.2.
  24. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.G.5.
  25. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.E.1.
  26. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.H.2.


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