Sinclair ZX80 / ZX81 / Z88 Forums

Good point Rich, its got the same edge connector as the ZX 81 and to be honest I didn't even consider that it could be used for the Spectrum. I have found pictures of the ZX81 version and it is the same as this one. But Cheetah maybe used the same layout/connectors for the Spectrum as it would mean ...

Nah, soldered the socket back in and still nothing....

http://www.retro8.co.uk/WebPics/cheet1.jpg


http://www.retro8.co.uk/WebPics/cheet2.jpg

ICs are 74LS366AN & 74LS138N

I may have found the problem, the pins from the 9 pin D Plug as not all soldered to the PCB.

I picked up a ZX81 Cheetah joystick interface today. I thought it would emulate the cursor keys and 0 but nothing seems to happen when I try it with an Atari type joystick.

There doesnt seem to be anything on the web. Can anyone say how it is supposed to work or provide info on compatible games.

Thanks Sasha,

SirMorris could you PM me when its ready and I'll send payment.

Thanks also to everyone else who commented or helped. This is why I think this forum is the best.

Dave

Thanks Rich, couldn't ask for more.

Dave

Hello Charlie

If you know Sasha and he can help its possibly easier and quicker. Let me know how much I'll owe you. Can I pay by Paypal?

Otherwise I'll try to get the JED file.

Thanks a lot,

Dave

Hi, Im looking for some help. I have a MR-X sound card. The GAL chip on it got very warm and it no longer works. As there are only two ICs - GAL and AY sound chip it should be an easy fix, except I cant source the GALs. Is there anyone who could program a GAL for me? I'll be happy to pay for the GAL...

Thanks Pokemon,

I used the same 16K RAM pack on all boards. Only the "Working ZX 81" produces a picture.

Revisited the ROM on one of the boards and get similar signals to the working ROM, so I guess the ROMs may not be bad.

Would any of the transistors or capacitors cause the loss of a picture?.

Hi, I've got three ZX 81 boards that I'd like to get working again. Realistically I think 2 can be repaired, the other seems to give 5V on just about every pin at the 3 main ICs. I have an oscilloscope, a decent multimeter and a working ZX81 to make comparisons with. Although all ICs in that are sol...