Weird eclipse on a MS-2931 chassis

[hrist]

Hi there!

I've got a ms-2931 who developed the behaviour of the photos below. Chassis will power up normally then the screen will become black progressively from left to right. Never seen the "eclipse" go more than half the screen though.
Chassis was recapped and the issue persisted.

Any pointers would be really appreciated!

 

[trashedcabs]

I've had a similar issue on a different chassis and it ended up being a ceramic cap failed causing the blanking signal at the end of a horizontal sweep cycle running too long and causing the start of the next cycle to also blank.

U101 is responsible for sync processing and generating the blanking signal which feeds to the video amp. I would check the components around there.

EDIT: Also, if you have cold spray, try hitting the video amp U201 with it while it's running and see if the problem goes away. I have had these Sony video amps fail before.