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Discussion Starter · #1 ·
I know i ask a lot of questions.


As you probablu know by now my neckboard broke and made a horrible burn-in in my new tube.


Now i am trying to figure out what caused it to fail.

I have been thinking alot and came up with this:


The pj worked for a week (table setup) i then made all changes for ceiling mounting. And if i remember correct, after that the pj behaved strange

when i switched resolutions. I had just built a HTPC and setup 1440x1152 resolutions. When the pj switched mode it did not seem to fire up and close down the beam correctly.


When switching to hires there was a pause as it should be, but it didn't seem to wait long enough for stablizing the beam. So when the image came on it was BIG and VERY out of focus, and it took about 1-2 seconds to shrink and focus the image. I can't remeber it doing so when it was table setup. And it did not do like this when switching between frequencies in the lower range. Only those above 64khz or so.


Well it only worked for 2 days, then came the neckboard breakdown..


My question now is:

Could there be something wrong with the deflection board or horizontal/vertical board (the one in the front) that should be looked at before mounting a new board and tube?


Hoping for some answers.


/Anders
 

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My old Sony 1030Q1 did exactly the same thing. It worked perfectly for a year on a coffee table. When I finished my HT room, I ceiling mounted it. After a couple of days of good service up there, I turned it off and it burned the phosphor away in a squiggle pattern on all three tubes right in the center.


Perhaps its something coming lose after years on its back, maybe the chassis twisted cracking something during the ceiling mount.


I dunno.


I scrapped it out and upgraded so it all turned out okay in the end.


- Rick
 

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Discussion Starter · #3 ·
Ick!, that was even worse..


Now i atleast know i have to be very careful in the future..


/Anders
 

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Several situations I've encountered come to mind when I read this thread:


The first is related to a BG800 that stopped functioning and I'm currently working on for a friend. One of the first things I noticed was that the 4 high voltage leads going into the splitter were all lose. The plastic locking nut wasn't engaged at all in some cases. This projector has only been used in table-top mode, but had it been ceiling mounted those leads would have started to fall out over time if not immediately. I'm actually thinking this may still be the source of the failed parts in this unit if those 34 kVolt connections might have been lose and arced. I've had to replace about half the boards so far.


The second situation was on this same BG800. On power-down the red tube would put a bright spot in the center of the tube (it hadn't burned through yet). I'm trying to recall, but when I swapped out the input switch board or the quad decoder it went away. I need to go back and recreate that one so I can check another projector that was doing this.


The third situation was with my personal BG800 about 3 years ago. The picture started growing and losing focus. Especially if I was watching a dark scene and it suddenly went bright. It turned out that my splitter went bad and finally took out my EHT board as well.


Were you able to notice if all three tubes bloomed and went out of focus, or was it just the red? I'm merely guessing of course, but I'd almost say the neck board and the tube are the victim and not the cause. I wouldn't replace the tube until you're sure. I have no real idea why 64 kHz could be a trouble threshold?


Mark
 
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