ZX81 with white screen

[jaume]

Hello.

I bought a ZX81 issue 3 and all the screen is white but the cursor don't appears. Anyone has seen this problem before?
I'm using an old b/w TV to test it. With a new CRT color TV, the screen is totally black.

Thank you very much.

[sirmorris]

Hi, welcome.

This is a common problem and searching the forum will turn up some information.

c

[PokeMon]

I think this is the same like my ISS 3 bought over ebay as "untested".
I think 90% of sold untested objects are waste.

I think the ULA is dead like mine and bring only sync pulses, no pixels.
If you have a scope you can scan the signal.
You will find the difference with working and non working ULA in this thread.

viewtopic.php?t=606