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Daddy
Joined: 16 Jul 2010
Posts: 13
Location: Netherlands
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| Posted: Sun Aug 19, 2012 1:14 pm Post subject: Problem with Sony G70 / ZONE & blowup of PA (twice) ?! |
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Hello,
I seek some help from the professionals here.
I have Sony G70 and enjoy it already for years.
There is a tiny bit of wear on the green tube that is visable when watching (black & white) 4:3 movies.
After a lot of searching I was finalily able to find an almost pristine green tube but without the coils.
So I took out the old tube, put its coild onto the newer one and mounted everything back.
All was fine initially.
But when doing the convergence I noted that the ZONE command worked only a tiny bit. This was so for all tubes. In other words I needed a masive amount of ZONE to achive only a small correction. So I may have overstrained the system?
When I was finaly watching a movie I suddenly heard a snapping sound and lost video on all tubes. The status indicates error 21 but noting wrong with the tubes/necks.
When the problem occured the PJ was open and I could see a tiny white spark near the PA board assembly. As if there was some arching from one of the tube HV leads to the chassis. But there is no visable damage.
Well... I do have a second Sony G70 with no tubes and so I replaced the tubes into the other G70.
All was well initially except that the ZONE problem was similar (although I am now using an entirely different chassis with a different PA board).
After a few hours of watching movies I heard the same crack and off went all tubes. Again error 21.
When I start the PJ the fans start whirling but in less than one second the system switches off and shows this error message.
QUESTIONS
(a) Is anyone of you familiar with the ZONE problem I encountered
(b) Is it possible that setting too many ZONES at MAX or MIN will cause a strain for ther system that can result in error 21?
(c) How do I detect if it is the PA board?
(d) Can it be repaired?
I hope somebody has an idea of what is causing my G70 problems.
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Sun Aug 19, 2012 1:45 pm Post subject: |
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You most likely have two issues. One, the DC board (convergence) board is bad. very common on G70s.
Second, the PA board is bad. You may also have HV leads to the tubes that need replacing, as they are now 15 years old or so. Eac time you heard the pop, that was an HV arc, and it demaged the PA board. I can fix the PA board and the DC board and have new HV leads in stock. Email me at curtpalme at shaw.ca on pricing and instructions how to send them in.
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AFryia
Joined: 09 Mar 2006
Posts: 965
Location: S.E. Michigan VPH-G70Q
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| Posted: Sun Aug 19, 2012 3:18 pm Post subject: Re: Problem with Sony G70 / ZONE & blowup of PA (twice) |
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| Daddy wrote: |
(b) Is it possible that setting too many ZONES at MAX or MIN will cause a strain for ther system that can result in error 21?
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How many Zones?
I have one or two at MIN or MAX, the corner zones I believe. Been like that for years without a problem. I have the rasters maximized so it is almost unavoidable in the corners.
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Daddy
Joined: 16 Jul 2010
Posts: 13
Location: Netherlands
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| Posted: Tue Aug 21, 2012 12:13 pm Post subject: Re: Problem with Sony G70 / ZONE & blowup of PA (twice) |
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| AFryia wrote: | | Daddy wrote: |
(b) Is it possible that setting too many ZONES at MAX or MIN will cause a strain for ther system that can result in error 21?
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How many Zones?
I have one or two at MIN or MAX, the corner zones I believe. Been like that for years without a problem. I have the rasters maximized so it is almost unavoidable in the corners. |
Well I cannot check it now as the PJ seems dead but as I remember all the ZONES at and near the corners were set at either MAX or MIN. Then only setting that seemed normalwas the center ZONE. That one responded just like centering RGB.
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Tue Aug 21, 2012 4:41 pm Post subject: Re: Problem with Sony G70 / ZONE & blowup of PA (twice) |
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| Daddy wrote: | | Well I cannot check it now as the PJ seems dead but as I remember all the ZONES at and near the corners were set at either MAX or MIN. Then only setting that seemed normalwas the center ZONE. That one responded just like centering RGB. |
If you had all zones near the corners at or near max/min, then you weren't doing enough work using all the other geometry controls. If your geometry is setup right, you will need almost no zone convergnce - just a half dozen or a dozen ticks here and there.
To do geometry right, you use size, lin, skew, bow, key, and pin in pairs, and work it iteratively. Size and lin together, skew and key together, bow and pin together. Go back and forth and back and forth until everything lines up. It takes practice and patience, but you should be able to got the picture to what I'd consider the 98% point without using a single bit of zone. Once that's done, you move on to zone to eek out the last 2 or 3%.
SC
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Tue Aug 21, 2012 7:20 pm Post subject: |
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like Curt said, the Green tube you put in probably had a leak around the HV cable. When you installed it and it arced into the chassis is damaged the machine. That would have been a good time ot ask a question here.
When you installed it in the second machine it damaged that one too.
This has nothing to do with zone convergence.
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Tue Aug 21, 2012 7:31 pm Post subject: |
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| draganm wrote: | | This has nothing to do with zone convergence. |
You're probably right, since in this case, there was the tube swap and then the arc. Pretty simple if-then.
But there also does seem to be a correlation between PA board failures and people doing convergence. I don't know how many times I've read over this over the years: "I've been using this machine for <insert long time period> and it's worked perfectly... Well, I just got a new BD player and HD Fury/Moome/HTPC and I was converging the new resolution, and pop!". Every time it turns out to be the PA board. Common failure, I know... But the failure always seems to coincide with convergence activities. It's extremely common.
SC
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Wed Aug 22, 2012 3:39 pm Post subject: |
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| ecrabb wrote: | | draganm wrote: | | This has nothing to do with zone convergence. |
You're probably right, since in this case, there was the tube swap and then the arc. Pretty simple if-then.
But there also does seem to be a correlation between PA board failures and people doing convergence. I don't know how many times I've read over this over the years: "I've been using this machine for <insert long time period> and it's worked perfectly... Well, I just got a new BD player and HD Fury/Moome/HTPC and I was converging the new resolution, and pop!". Every time it turns out to be the PA board. Common failure, I know... But the failure always seems to coincide with convergence activities. It's extremely common.
SC |
well beyond me thouhg, Curt's the only one qualified to comment on whether there's any electronic correlation bewteen the DC board/convergence circuit and the PA board. It might very well be, Sony seemed to tie almost everything together in their machines.
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