Sony PVM 20M4E - No Picture, No Menu (Except When Underscan Button Pressed)

[pvmhelp]

Hi All, really hoping someone can help me diagnose an issue on my PVM 20M4E.

As per the title, I have no picture or menu except when putting it into underscan mode. (I'm hoping that can help to narrow things down!).

Before I realised the picture / menu worked in underscan mode I took a shotgun approach.

G-Board

• Replaced three regulators c603, c604 and c605.

A Board

• Replaced the HOT (Q501). (There were visible signs that the solder had melted, so I was sure that was the issue. The rest of the board looks good.

History:

Last year I used Savon Pats kit to replace select capacitors on the A board. I could be that there's a dry joint (especially with my soldering), but visually I couldn't see an issue.

I'm really hoping that it works in underscan mode is enough of a clue to narrow things down.

I'm really stumped about the next steps to take. Any advice is greatly appreciated.

[Deep_wolf]

You can try to touch and move some elements on the board in order to inspect if are there any bad joints. Also use a flashlight, if you can't trust your eyes. Some general tips mate.

[pvmhelp]

Thanks for the tips, that's useful advice. Appreciate it.

I'm wondering if anyone knows if the underscan portion working, narrows it down somewhat. (Maybe today is the day I learn to read a schematic!)

[pvmhelp]

I reflowed the solder on the A board last night and nothing.

I've just invested in an ESR meter which should be here in a few days.

Currently working theory it's an out of tolerance cap - which could explain why the under scan setting works as it has less work to do to only show half of the image. (Not an expert, but has to be something along those lines).

I'll update the post once I've tested.