Sony VPH-722QM CRT projector, coolant problem?

[Thomas Tornblom]

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]

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]

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

Cheers,
Thomas

 

[John Del]

Subject: Re: Sony VPH-722QM CRT projector, coolant problem?

From: Thomas Tornblom [email protected]-to-reply

.. I found some articles that says that Sony doesn't

support or recommend replacing the fluid.

Sony doesn't, but replacing the tubes makes no economic sense either. I've
done several dozen Sonys over the years with contaminated coolant. Most work
perfectly, but some have degradation of the allow housing that causes the
coolant to get cloudy after a couple of years.

Some models also had sealed tube assy's that needed to be literally cut apart
and carefully resealed to do, but at the age these models are at, I wouldn't do
another.

John Del
Wolcott, CT

"I'm just trying to get into heaven, I'm not running for Jesus!"
Homer Simpson

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