ZX-81 Corrupted text display

[1024MAK]

^ what Moggy said

It’s not until you eyes age and make life more difficult that you appreciate how good you eyes were when you were younger

I now keep a cheap illuminated magnifying glass (okay, it has a plastic lens) on my bench, in addition to good lighting, so that I can see fine details.

Mark

[Moggy]

It's not only me with the lens and the lights then!?

[Jelvis]

Oh ye of little faith. I knew i should have put a pic up of the other side of the board to

Couldn't agree more about lighting and magnification, my eyes are all about extra photons these days.

Mike

[Jelvis]

Just a final update. New ULA 81 fitted in a socket from Charles at vRetro who I have to thank for getting the chip from New Zealand to the UK in under a week from ordering!!

I still have a few bits to do, check mic and ear sockets for correct operation, replace regulator with something more modern, some sort of bypass for the modulator and check the 16K pack I got with it but it now appears to be working as intended without the graphics corruption.

Once more thanks again to everyone who get me here with their suggestions and checks.

Mike

[Moggy]

Another one back in the land of the living, well done Jelvis your persistence paid off!

[redgatemodels]

[1024MAK]

Good news

If doing further work, please do take precautions against static and make sure the board has been powered down for at least a couple of minutes before starting work. This is because the vLA81 is not as hardy as the old technology ULA.

Also be careful with the expansion port/edge-connector.

Mark