CurtPalme.com Home Theater Forum

[Scott]

Hi,

I have a Sony 1251 that I've been using for about 8 years that just started having sudden focus loss issues about a week ago. After about 1.5-3 hours of operation, the focus suddenly goes bad. It seems to affect all the CRTs at once, but not equally; Blue is the worst, followed by the green, then the red. In the H-shaped test pattern, you can't see any shapes in the blue, you can only make out boxes in the green, and the H shapes in the red are just fuzzy. I just noticed last night that after the focus goes bad, it will sometimes get worse, then come back to bad, but never fully back into proper focus.

If I shut the projector off and restart it right away, the projector is still out of focus. However, if it is shut off overnight and allowed to cool, it starts out great, but then will suddenly go fuzzy sometime between 1.5 and 3 hours of use, depending on the day.

I'm thinking that this is caused by a bad board or part of a board that controls High voltage and/or focus, but I don't know where to begin looking for the source of the problem. If anyone has any ideas, I would love to hear 'em.

thanks!
Scott

[Curt Palme]

This is a bit unusual for a Sony, but it is most likely the focus control block itself I'd think. That or one of the CRT sockets is arcing internally, causing all focus voltages to drop a bit. I've got those parts for cheap, email me at curtpalme@shaw.ca.

Cheers!

[Curt Palme]

This is a bit unusual for a Sony, but it is most likely the focus control block itself I'd think. That or one of the CRT sockets is arcing internally, causing all focus voltages to drop a bit. I've got those parts for cheap, email me at curtpalme@shaw.ca.

Cheers!

[dropzone7]

[Scott]

Thanks!

You mentioned that one of the CRT sockets could be arcing internally. I should probably mention that about once a year for the past 3 or 4 years there would be an arcing sound and the picture would dim simultaneously. It would only last about a second and it might do it two or three times in one minute, after that it wouldn't do it again for another year or so. I never really thought of it as a big problem, as it only happened about once a year and didn't really affect the performance of the projector for very long.

However, last week just before we started getting the focus problem, it arced twice and about 2 minutes later, the focus went bad. This was the first time we ever had that happen. We kind of looked around each-other with concerned looks and hoped it would come back into focus- It did about 5 minutes later, stayed working for another 5 minutes and then went bad again. It stayed that way for the rest of the night.

The next night we started it up again, and it behaved just like I explained in my previous post, No arching at all from there on out.

I didn't mention it before, because I thought that the focus and arcing were separate issues, but since you brought up arcing, I thought I'd better mention it. Maybe it will help to narrow down the source of the problem.

thanks again!

[Curt Palme]

Got your email, replying to it tomorrow. House cleaning day today. Sending out one last parts shipment before the 25th on Monday, so check your email tomorrow..

Thanks!

[Curt Palme]

Got your email, replying to it tomorrow. House cleaning day today. Sending out one last parts shipment before the 25th on Monday, so check your email tomorrow..

Thanks!

[Scott]

Sounds good. thanks!