ChicagoJohn
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Mar 12, 2008, 7:43 AM
Post #1 of 1
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Philips 30PW9100D/37 Thin White horizontal line
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I own a Philips 30PW9100D/37 HDTV that I've owned for about a year. It has a LO5.1UAA chassis.
A couple of months ago, it began an intermittent problem where it would form a thin white line on start up:
http://www.johnabbott.net/images/philips/IMG_7963.JPG
(sample)
I found that by turning it off and on several times, it eliminated the problem for a month or so.
Most recently, the problem "stuck". I tried turning it on and off, only to find this problem:
http://www.johnabbott.net/images/philips/IMG_7957.JPG
The bottom half of the screen white, distorted, and out of alignment. Occasionally, it would appear brighter, and then shut off after 30 seconds or so.
http://www.johnabbott.net/images/philips/IMG_7960.JPG
After much searching online, I've found that this seems to be a familiar problem with Philips sets, particularly a 27 inch. But since its a different chassis, I can't match the parts.
I also found a service manual for the set, so I've been able to take it apart and look for burnt resistors and bad capacitors. But as of yet, nothing has stuck out.
The LED on the front of the set blinks a code that doesn't seem to match any of the error codes I've found. (It seems to be 8, followed by 34, followed by 33.)
The service manual suggests, on a thin horizontal line, to check three transistors at the Vertical Deflection circuitry.
My questions:
There is a deflection board that stands up on the side, and is separate from the mainboard. Is this part of the vertical deflection circuit?
Two of the three transistors that it asks me to check (7451, 7523, and 7543) seem to be on the mainboard, but I can't get to them easily and don't know how to check them. Is there a way to check them with the power off?
If not, is it okay just to replace them?
The third transistor (7523) doesn't seem to exist on the board or the parts list. Now what do I do?
And then there is this:
http://www.johnabbott.net/images/philips/IMG_7987.JPG
Note the resistor in the center. When I removed the deflector circuit board, I found that resistor soldered between two points. It doesn't exist on my schematics. , or PCB layout from the service manual.
The set was bought as an open-box item, but this appears to be some sort of nasty repair job? Or am I completely wrong?
Where do I start?
Is the deflection board (the one I can remove) a vertical or horizontal deflection board? If its a horizontal deflection board, can I assume that the problem is not there... but somehwhere on the mainboard.
Also, while following other suggestions on what to check, I found resistor 3414; which is supposed to be 4.7 ohms on my parts list, but is coming up on my multimeter as 90plus ohms. Is that significant, or more likely a bad reading?
Any and all help is appreciated, and I'm pretty much willing to try anything.
-John
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