Timex/Sinclair 1000 not displaying correct key pressed.

[gs80065xe]

A boxed Timex/Sinclair 1000 I recently purchased arrived today. I decided I wanted to see something like what the folks in the UK had when I was using my Atari 800.

 

The seller said it was untested. But it appeared to have never been used. First I tested the 9VDC power supply with an analog and digital meter. It was reading about 11 - 12VDC on the analog meter. Higher on the digital. About 14V. But they both read higher than rated on some other DC adapters I have. So I plugged it into the PC without connecting to the TV. Well, there was no sound, smoke or heat right away. So I hooked it to the LCD TV. Turned it on. First wasn't sure it was working. A lot of interference on the TV. Even in the sound. So I muted that. The K appears in the lower left. I tried typing some keys. But what I pressed did not translate to the screen. So I thought maybe keyboard. But then I pressed P, which should automatically display the PRINT keyword. It didn't print PRINT. And each time it was different variation of a 5 character word. So is this a bad keyboard or something at the board level?

 

Thanks,

Glenn

 

[DragonGrafx-16]

Not really what they used over there. That would be the ZX Spectrum... the 1000 was just too basic to play games or anything at all really.

Edited April 13, 2019 by DragonGrafx-16

[mr_me]

The timex sinclair would be comparable to the zx81, the precursor to the popular zx spectrum.

 

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Those old unregulated ac adaptors will read high without load. Are you saying only the 'p' key responds.

[Nukey Shay]

Not interpreting correct keypress...bad Ram?

[monzamess]

Try https://sinclairzxworld.com. There is still an active ZX81/TS1000 community on this planet, and that is where they hang out.

 

The ribbon cable from the keyboard to the motherboard dries out and cracks so even brand-new-in-box units are likely to have bad keyboards. Luckily you can buy reproduction replacements and even upgrades. For that, try https://www.sellmyretro.com

Edited April 13, 2019 by monzamess

[JamesD]

The ZX-80/81 were actually quite popular in the UK for a while since they were the most affordable machines until more powerful computers like the Spectrum came out in 1982.
The TS-1000 sold over 1 million machines in a single year in the US, but people in the US had higher expectations.
I found a TS-1000 at a yard sale for $10 in 1983, only 1 year after they came out. No I didn't buy it.

The keyboard membranes tend to fail, but keys just stop working when that happens.
If the input is changing, that's going to require a look at what is happening on the buss when you type a key.
Sounds like noise on the buss and the voltage levels of signals are borderline.
That is totally a guess though. It could just be a bad chip. Luckily the original ZX-80 was mostly off the shelf parts, which is why there were so many clones.

The video output on the one I had was crap. There are several pages dedicated to that.

It seems like a lot of work for the machine.

[carlsson]

The power adapter probably is linear which means it is fairly normal to get 12-14V without load, down to 9-10V once you have a load.

[RWAP]

Getting the wrong keyword when you press a key is not a fault of the keyboard membrane normally - it could be anything from a corrupt ROM chip to a leaky cap somewhere. Asking on www.sinclairzxworld.com is probably your best bet