My K prompt has faded!

[djp]

Not sure what has happened, but as of today, my ZX81's screen has gone weird. The K prompt is hardly visible, like it's washed out. It is there, but appears as if someone has messed with the brightness/contrast. I've removed the attached ZXpand and AY expansion, but still the same problem. I'm wondering if it is the lead itself from the TV out to my PVM? Could a damaged lead cause such an issue? If so, I'll try and get hold of one and give that a try.

Any advice, most appreciated.

[Vorticon]

Are you using a modulator or do you have the composite mod?
For the latter, this sounds like a component failure, likely the transistor amplifying the signal from the ULA. If you are seeing a K prompt, that means the computer itself is working for the most part.

[Moggy]

The only occasion I can recall something similar happening to me is when the composite signal to the TV was too strong from the simple composite mod I did and I had to exchange the 100 ohm resistor to a 50 ohm from signal to ground to tap off the excess signal.

It is possible that your working monitors internal resistance has now broken down hence the sudden washout effect.

[djp]

Thank you for the responses Vorticon and Moggy.

Are you using a modulator or do you have the composite mod?

It's fitted with the composite mod.

The only occasion I can recall something similar happening to me is when the composite signal to the TV was too strong from the simple composite mod I did and I had to exchange the 100 ohm resistor to a 50 ohm from signal to ground to tap off the excess signal.

It is possible that your working monitors internal resistance has now broken down hence the sudden washout effect.

I've tried the ZX81 on a different monitor and also with a different power supply, but same issue.

As Vorticon mentioned, if I'm seeing a K prompt, the ZX81 is working for the most part. Just difficult to see any characters on screen.