dstromb
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 Posted:
Mon Feb 14, 2005 9:23 am Post subject:
Pioneer rear projection tv: convergence or deflection? |
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I recently picked up, on the cheap, a Pro-98 Pioneer rear projection T
whose picture is collapsed over roughly the top half of the screen
down to the middle. In case that description doesn't make sense,
picture is here (just snow, nothing hooked to tuner):
http://209.234.77.62/tmp/pro98_raster.jpg
There are no visibly obvious problems on the deflection or convergenc
boards; I did touch up some suspect-looking solder points on bot
boards to no effect. I don't have a schematic (yet anyway) but th
voltages at the test points I can find are about right. The guy
bought it from said it had failed in "exactly the same way" onc
before, and a Pioneer dealer had replaced a board, he didn't know whic
one. I did notice that on the convergence board, the large IC (STK4277
looked like it had been soldered in by hand, so I assume that's what th
dealer really did. But when people say things have failed "exactly th
same way" before, that isn't always true - sometimes they don't reall
remember what it looked like, they just remember it was wrong. So it'
hard to trust that.
Based on some other reading suggesting that STK4277 chip commonl
fails, I've ordered one - they can be had for under $20 - but the mor
I look at the symptom, the harder it is for me to believe tha
convergence has anything to do with making half the picture go that fa
out of whack, and there must be something wrong on the deflectio
board.
When the chip arrives later this week, I'll know whether the firs
impulse was right, but does anyone recognize the symptom
--
dstromb
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