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timex/sinclair 1500:

	quick facts

Overview Photograph
FCC ID	CEC8E41500M338R01
Model or Part #	M-338
My unit's vintage	Serial #P067128KN
CPU	Z-80A (actually an NEC 780-1, which is a pin-compatible part).
Memory	16K DRAM, 8K ROM
Operating System	Sinclair floating-point BASIC.
Ports	Standard 3.5mm mono jacks for tape recorder microphone and earphone connections, and an expansion edge connector at the rear of the machine.
Video/audio output	The TS1500's capabilities are identical to the ZX81 and TS1000; it has essentially text-only, black and white video, and no sound output capability. Primitive block graphics are available (four pixels per character space). Although the character set is reprogrammable, and could in theory be used to generate high-resolution graphics, due to a hardware quirk the character set must be fetched from ROM and therefore can't be usefully altered.
Available peripherals	The TS1500 should be compatible with Sinclair's ZX printer, and other ZX-81 and TS1000 peripherals.

The TS1500 is a mavericky beast that was sold only in North America, as far as I know. In the scheme of transatlantic Sinclair models, it lies between the ZX81 (Timex 1000) and the original ZX Spectrum (Timex 2000 in the US). The case styling is almost identical to a 16K or 48K "rubbery" ZX Spectrum, except that it's made of a groovy silver plastic instead of the Spectrum's sedate black. The case even has speaker holes where the ZX Spectrum has them, although the TS1500 has no sound capabilities.

From a user's standpoint, the TS1500 is nothing more than a ZX81 (TS1000) with a slightly better keyboard (chiclet calculator keys instead of a dead membrane) and the 16K RAM pack included internally instead of being an add-on. Electrically, it is somewhat different from the ZX81 - the 40-pin SCL chip from the ZX81 has been replaced by a 68-pin PLCC custom chip from Timex. Oddly, the integration level seems to be lower in the TS1500; it has more parts than the TS1000/ZX81! The only functional difference I can find is that the RF modulator has software switching between channels 2 and 3 (it powers up on channel 2 by default; press 3 immediately after powerup and it switches to channel 3).

The machine was apparently a monumental flop, which isn't surprising. The unit I have was sold as part of an educational set, from some kind of educate-yourself-at-home university called "National Education Corporation". They sold the unit in a custom-fit plastic briefcase with the Timex/Sinclair 2022 tape recorder, Psion's Vu-Calc, and proprietary learning software, along with a bundle of thin silver booklets containing the course material.

This machine is fairly rare. I paid a little over US$100 for my mint-condition ex-teaching system (illustrated below) with its plastic briefcase, and I have reason to believe that was a rather good price. I only bought it out of a sense of collecting, however; if you want to immerse yourself in the early ZX experience, you would be better off buying a ZX81 or TS1000.

	downloads

Please see the ZX81's emulator section for information on emulating the TS1500.