I readjusted the covergence on my trusty old Sony VPH-722QM CRT
projector yesterday, and when I looked into the lenses I saw that the
blue tube had quite a lot of specks on what looked to be the front
surface. Is that bacteria growth of the type I've been hearing about
with liquid cooled CRT projectors?

I skimmed through the Operation and Service Manuals, but couldn't find
any procedure for replacing the coolant. Is it possible to replace it
on these, and are there any gotchas for doing it?

Cheers,
Thomas

I think Sony has always recommended replacing the CRT and not replacing the
coolant, so you are mostly on your own in terms of procedures. Most CRTs
are pretty simple to do, though I don't ever recall seeing bad coolant on
one of these. Are you sure that it is not just phosphor aging?

Leonard

"Thomas Tornblom" -to-reply wrote in message
...

I readjusted the covergence on my trusty old Sony VPH-722QM CRT
projector yesterday, and when I looked into the lenses I saw that the
blue tube had quite a lot of specks on what looked to be the front
surface. Is that bacteria growth of the type I've been hearing about
with liquid cooled CRT projectors?

I skimmed through the Operation and Service Manuals, but couldn't find
any procedure for replacing the coolant. Is it possible to replace it
on these, and are there any gotchas for doing it?

Cheers,
Thomas

"Leonard Caillouet" writes:

I think Sony has always recommended replacing the CRT and not replacing the
coolant, so you are mostly on your own in terms of procedures. Most CRTs
are pretty simple to do, though I don't ever recall seeing bad coolant on
one of these. Are you sure that it is not just phosphor aging?

Thanks for the info. I found some articles that says that Sony doesn't
support or recommend replacing the fluid.

I have checked further, and the specks are not related to the
image. If I move my head while looking into the tube, the specks move
relative to the image shown.

I'm beginning to suspect dust.

Here are some images I just took:
http://www.hax.se/~thomas/146-4630_IMG.JPG
http://www.hax.se/~thomas/146-4631_IMG.JPG
http://www.hax.se/~thomas/146-4632_IMG.JPG

They are not good by any means, but they do show that it is only the
blue tube that has these specks.

Is it possible for dust to enter between the lens and the CRT?


Leonard

"Thomas Tornblom" -to-reply wrote in message
...

I readjusted the covergence on my trusty old Sony VPH-722QM CRT
projector yesterday, and when I looked into the lenses I saw that the
blue tube had quite a lot of specks on what looked to be the front
surface. Is that bacteria growth of the type I've been hearing about
with liquid cooled CRT projectors?

I skimmed through the Operation and Service Manuals, but couldn't find
any procedure for replacing the coolant. Is it possible to replace it
on these, and are there any gotchas for doing it?

Cheers,
Thomas



Cheers,
Thomas