Grey screen / interference on PSOne/Zenith

[MegatronUK]

My Zenith screen has been working fine in RGB mode until a recently - however it's now showing a sort of grey interference over the top of everything - colours are inverted and even the OSD does not show clearly - it should be bright green, but its a fuzzy grey colour with slight touches of green.



If I disconnect everything and just have the +7.5v and ground connections it's the same.
I can't think of anything I've done that would have caused this - since attaching the board and screen to the standoffs in my case and testing it, I haven't touched the display for two weeks or so (been working on the controls and keyboard).

I'm grasping at straws here, but wondered if anyone else had seen similar display problems and managed to track down the cause? (faulty lcd flat cable perhaps?).

[MegatronUK]

AAAAARGH!!

I'm such an idiot!

Before testing any equipment, make sure that the output voltage selector on your new DC power supply actually does what it says. Selecting 7.5v output it not supposed to output 9v!

Selecting the next voltage down (marked as 6v), actually outputs the correct 7.5v and the screen is once again rock steady and the OSD is a bright, crisp green.

I think I'll go back to my trusty Canon digital camera power supply, at least I know that it outputs exactly what I select.....

[Life of Brian]

That was a close one! Any higher and you would have been looking for a new screen.