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Jesse S
Joined: 12 May 2007
Posts: 209
Location: Etobicoke
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| Posted: Fri May 09, 2008 2:07 am Post subject: XG - problem with picture shifting |
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I'm having a problem with my XG. When I first turn it on the image is often spilling off the left side of the screen. After it warms up for 5-30 minutes (it varies which is annoying), the image suddenly shrinks from the left side. I thought the memory block might be corrupt so I deleted all of them and did the setup fresh but it's still happening, except now it fits when I turn it on and then it shrinks from the left and is too small for the screen. When it shifts the static convergence is off and even some of the other parameters like tilt/skew are a bit off suddenly so it's not just amplitude.
Rasters are well centered, image is centered within the raster and static convergence is near 0,0 for red and blue as tube toe-in is correct and I adjusted raster centering to eliminate all but a tiny tweak of static for vertical convergence. The projector itself is ceiling mounted and pretty close to center as green fits the screen well with raster/image centered, so the pj is not "fighting" a bad mechanical setup.
Where do I start to track down the culprit?
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Fri May 09, 2008 3:16 am Post subject: |
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Is it consistant in doing this? Meaning does it always start larger then after a certain amount of time then shrinks smaller every time you use it? If you shut it down then turn it right back on again is it still small or large again or does it have to be off for a certain amount of time before its large again when you turn it on?
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jarseneau
Joined: 06 Nov 2007
Posts: 323
Location: WI
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| Posted: Fri May 09, 2008 3:47 am Post subject: |
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I have seen this a couple of times and fixed it by replacing the Horizontal deflection (H-Def) board. That's the board on the hinged platform above the CRTs with the large heatsink. I'm sure you could track down the component on the board but I've found these at less than $100 and haven't spent the time to find it. I would guess you can send the board in to Curt and have him check it over. (or maybe he can name the component)  .
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Jerry
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Jesse S
Joined: 12 May 2007
Posts: 209
Location: Etobicoke
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| Posted: Fri May 09, 2008 4:05 am Post subject: |
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I think it's a warming up thing. I'll check that tomorrow.
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jarseneau
Joined: 06 Nov 2007
Posts: 323
Location: WI
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| Posted: Fri May 09, 2008 4:36 am Post subject: |
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| Jesse S wrote: | | I think it's a warming up thing. I'll check that tomorrow. |
Yes. Something heats up on the H-Def board and if you watch the left side during that 5-30min period it will do the shrink thing over a 3 second time span as it collapses. I've tried spraying component cooler on various IC's on the board but couldn't locate the culprit. I never tried the big transistors on the heat sink so they may be a prime suspect.
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Jerry
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Jesse S
Joined: 12 May 2007
Posts: 209
Location: Etobicoke
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| Posted: Sun May 18, 2008 6:54 am Post subject: |
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It might be caused by the little fan, 60mm or so that blows air through that heatsink on top. I was slowing that a bit and I removed the zener tonight and it didn't "shrink" after warming up.
It's a very irritating fan unfortunately, with a high pitch whine. It's orientation makes it hard to replace with a 120mm fan for example. It would be too tall for the top case to fit. Perhaps I'll just remove all the plastic casing and do a hush box.
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