Sinclair ZX80 / ZX81 / Z88 Forums

Hi,

I recently acquired a timex 1000. It has a bad picture. Being totally new to the internals of these machines, (I have not opened it up yet), what can I do to improve it ?
The picture status as of now is it has a solid gray, almost white background, and the characters have some shadow but little which I think it is quite acceptable, but the screen is sprinkled with moving dots. I will make a video showing it and post a link here.

I searched for solutions so far and came across the composite to HDMI converter route. I have one such device for another retro system. To use it I need to modify the UHF converter to composite right ? If so, Anyplace explains how to ?

Thanks,
Regards

I have fitted over 50 of these to ZX81s and the occasional 1000:

https://www.ginger-electronic.com/en/re ... -zx81.html

Very simple to fit - a few bits to desolder and a few wires to solder on. It gives a superb composite picture. If you go that route I can add installation details (as can many others on here).

Just bought the board. Hopefuly it will come from instructions, but if you want to share your experience installing these, please do.

Thanks,
Regards

It does come with instructions but a few photos always help!

I generally fit them underneath the motherboard, stuck with thick, high strength double sided tape.

On an issue one board:

An issue three board:
The other wires are for a Wespi (wifi board).

The brown wire goes into the modulator, attaching to the output. A couple of wires need to be detached from the modulator and a resistor.

There are a couple of adjustable pots that come pre-adjusted for the earlier type ULA that will probably need adjusting for your 1000.

This is a good starting point:


Always helps to take a photo of the current position before adjusting.

And a Timex 1000:


I did this before I realised it made more sense to stick the board to the underside of the motherboard - makes life easier when opening the case. Although this may be an issue with the metalised case of the 1000 so maybe it’s best where it is.

I really need to get round to replacing the voltage regulator on this one…