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Tandy 1000 TL

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Tandy 1000 TL
Tandy 1000 TL (Radio Shack catalogue RSC-20, 1989)
A Tandy 1000 TL with CM-11 monitor and Tandy serial mouse, from Radio Shack's 1989 computer catalogue
Specifications
ManufacturerTandy Corporation, sold by Radio Shack
TypeDesktop personal computer (IBM PC compatible)
CPUIntel 80286, 8 MHz or 4 MHz (software selectable); socket for an 80287
Memory640 KB, expandable to 768 KB (128 KB of it for video)
StorageOne 3.5-inch 720 KB floppy drive; room for two more floppy drives and a hard disk card
DisplayBuilt-in Tandy video: CGA compatible with extra modes, and Hercules-compatible monochrome
Sound8-bit DAC for sound and speech, with microphone input
PowerInternal supply, 67 W output, 120 V AC
OS / FirmwareMS-DOS 3.3 and DeskMate in ROM
Model no.25-1601

The Tandy 1000 TL is a desktop IBM PC compatible in the Tandy 1000 family, introduced in Radio Shack's 1989 catalogue. It pairs an 8 MHz 80286 with MS-DOS 3.3 and DeskMate in ROM, a battery-backed clock and the same video and sound hardware as the Tandy 1000 SL.[1] Wikipedia describes it as an update of the Tandy 1000 TX with a redesigned case. Wikipedia also notes that the TL series keeps the XT-class design of the earlier Tandy 1000s, so the TL cannot use extended memory despite its 80286.[2]

History

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The TL cost $1,299 in the 1989 catalogue, catalogue number 25-1601.[1] It was followed by the Tandy 1000 TL/2, which added a built-in hard disk interface, and the Tandy 1000 TL/3, which runs at 10 MHz.[2]

Specifications

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Tandy 1000 TL (Radio Shack catalogue, 1989)
Item Specification
Processor 80286, 8 MHz or 4 MHz, software selectable; optional 80287 maths coprocessor
Memory 640 KB RAM, expandable to 768 KB (640 KB for MS-DOS, 128 KB for video)
ROM 512 KB, holding MS-DOS 3.3 and DeskMate; 1024-bit EEPROM for the configuration
Video MDA or CGA compatible text; Hercules graphics (720 x 348); CGA graphics with enhancements (640 x 200 in 16 colours)
Sound 8-bit bidirectional DAC for sound and speech, internal speaker, 3.5 mm stereo headphone jack with volume control, 3.5 mm microphone jack
Storage One 3.5-inch 720 KB drive, 1 inch high; expandable to three floppy drives (two 3.5-inch, one 5.25-inch) and one hard disk card
Expansion Five 10-inch 8-bit PC bus slots
Ports Parallel printer port, RS-232 serial (9-pin male), two joystick ports, microphone in, headphone out
Clock Real-time clock and calendar with battery backup
Keyboard 101-key keyboard
Size 5.1 x 15.5 x 13.1 in (H x W x D); shipping weight 33 lb
Power 120 V AC, 50/60 Hz; supply output 67 W

Source: Radio Shack catalogue RSC-20.[1]

Hardware

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Processor and memory

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The 80286 and the 80287 socket are both on the main board. Radio Shack sold the 80287-8 for the TL, and an owner reports an 80287XL working in a TL/2.[3][4] The FAQ says Evergreen's 386 and 486 daughterboards, and Improve Technologies' "Make it 386" and "Make it 486", fit in place of the 80286 in the TL and TL/2 but not the TL/3.[5]

The extra 128 KB uses four 64K x 4 DRAMs of 120 ns in sockets U36 to U39, with no jumper to move. Because the video circuit takes memory back once DOS has 640 KB, adding the 128 KB gives DOS only 32 KB more.[6]

Video and sound

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The TL has the SL's Tandy Video II: digital CGA or monochrome TTL monitor, switched with Ctrl-Alt-Shift-V, Hercules compatible on a monochrome monitor, and a 640 x 200 16-colour mode.[7] The sound hardware matches the SL's, with an 8-bit DAC and microphone input.[1][2]

Storage

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The TL's 3.5-inch drives take their power through the data cable, so a standard drive cannot be fitted without modifying the cable.[8] One owner's TL has a Sony MP-F11W-70D drive.[9] The floppy controller runs at the low-density rate only; A reply from Radio Shack's computer support service, quoted in the FAQ, says that high-density drives are not supported in the TL and that the built-in controller cannot be disabled by jumpers or switches.[10] The TL has no built-in hard disk interface. The FAQ says most 8-bit hard disk controllers work, and that the system setup program must be set to boot from DISK to start from a hard disk.[11]

Keyboard, ports and clock

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The TL takes an XT keyboard (or an XT/AT switchable one) with a 5-pin DIN plug.[12] The printer port is a card-edge connector that needs a Tandy 1000 printer cable.[13] Unlike the SL, the TL has a clock with battery backup as standard; Wikipedia says it runs from a removable CR2032 cell.[1][2]

Power supply

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The catalogue gives the supply's output as 67 W from a 120 V AC, 50/60 Hz input.[1] No service data for the TL supply has been found. Tandy's Tandy 1000 TL Technical Reference Manual (25-1517) was sold for $49.95 in 1989.[14]

Known faults

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  • "Drive A critical error" at start-up with no disk in the drive. A TL with DOS in ROM should boot from ROM; Trixter suggests a bad or disabled ROM, or a bad boot-device setting in the EEPROM.[15]
  • The floppy drive fails to detect a disk change. One owner cleaned the switches and replaced the drive's two electrolytic capacitors without curing it.[9]
  • A corrupted EEPROM can leave the machine stopped at the memory count.[16]

See Tandy 1000 TL Troubleshooting Guide.

Documentation

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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Radio Shack, computer catalogue RSC-20 (1989), p. 18, "286-based Tandy 1000 TL for business and home offices", page scan at RadioShackCatalogs.com (retrieved 2026-10-22).
  2. ↑ 2.0 2.1 2.2 2.3 "Tandy 1000", Wikipedia (retrieved 2026-10-21). Sections "Tandy 1000 SL and TL series" and "1000 TL, TL/2 and TL/3".
  3. ↑ Radio Shack, computer catalogue RSC-21 (1990), p. 17, "Memory expansion/coprocessors", page scan at RadioShackCatalogs.com (retrieved 2026-10-22).
  4. ↑ "Compatible 287 math co-processor for a Tandy 1000TL", Vintage Computer Federation forum, August 2021, thread. Post by jasa1063, 17 August 2021.
  5. ↑ Jeff Hayes, "Tandy 1000-series FAQ", version 2.52, 25 October 2005, TVDog's Tandy 1000 archive (retrieved 2026-10-21). Sections II.F.1 and II.F.2.
  6. ↑ Hayes, "Tandy 1000-series FAQ" (2005), sections II.A.1, II.A.2 and II.A.3.
  7. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.B.5.
  8. ↑ Hayes, "Tandy 1000-series FAQ" (2005), sections II.C.2 and II.C.5.
  9. ↑ 9.0 9.1 "Disk change not working on Tandy 1000TL floppy drive", Vintage Computer Federation forum, January 2026, thread. Posts by jamonyorke (21 and 24 January 2026) and ldkraemer (24 January 2026).
  10. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.C.1.
  11. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.D.1.
  12. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.E.1.
  13. ↑ Hayes, "Tandy 1000-series FAQ" (2005), section II.H.2, printer cable selection grid.
  14. ↑ Radio Shack, computer catalogue RSC-20 (1989), p. 27, technical reference manuals, page scan at RadioShackCatalogs.com (retrieved 2026-10-22).
  15. ↑ "Tandy 1000TL drive A critical error on startup", Vintage Computer Federation forum, November 2020, thread. Posts by Dokken and Trixter, 10 November 2020.
  16. ↑ Hayes, "Tandy 1000-series FAQ" (2005), sections II.K.8 and III.F.2.


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