Sinclair ZX80 / ZX81 / Z88 Forums

I'm in the same situation with my ZX81 at the moment: white screen with no cursor.

Which finally was the damaged part in your case, the ULA or the Z80 ? I think that do you replaced one of them, tested the ZX81 and replaced the other one later it isn't?

Bukster wrote: ↑Sat May 04, 2019 1:10 am Welcome aboard. I hope the weather is better there than here in New Zealand

Thank you, usually it is

You have eliminated the RAM ??? No, both straps are open (LK1/2)… and we had to put a 16k ram pack to test the ram >>> rom boot. I soldered a jumper to connect LK2 but as it is under the green circuit in the picture is not possible to see it, but it is. I'll try to find a logic probe until the tran...

mrtinb wrote: ↑Wed May 01, 2019 7:28 pm A digital probe will help you find the problem if you don’t have an oscilloscope. Or even a voltmeter can help.

Andy from this forum has created a cheap ULA replacement.

https://www.sellmyretro.com/offer/details/32319

Hope he makes more soon.

Thank you for the information, it looks great!

Hello, Recently I purchased a damaged ZX81 and now I'm trying to repair it. The main problem (and the only one I hope) is that when the ZX81 is turned on I get a white screen but without cursor. The basic checks that I have done at the moment are: 1) PSU: Voltage is correct, around 14 volts without ...

Hi Papalapa I hope some of the information in this thread is useful to you. The members here are happy to help you if they can. I do suggest though that if you want advice and help with your machine, that you start a new thread. This saves any confusion with members getting confused between the pro...

I have the same problem than you on my ZX81: white screen with no cursor.

Did you finally solved the problem with your ZX81?

Hi there,

I'm glad to join this forum, I recently purchased an ZX81 that was my first home computer when I was young. Actually I'm doing some hardware modifications and that's why I come here to read and learn about.

Greetings from Catalonia!