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Old 11-16-2011, 04:37 PM   #1
sagie
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Join Date: Sep 2010
Posts: 10
Default Philips LCD TV with Sound, No Picture (model 42PFL5322/10)

Hello everybody,

First of all, many thanks for all of the good people that has been contributing here.
I got here about a year ago via Google search and was able to fix a malfunctioning LCD monitor by replacing some swollen caps, following just the advice I read here, with no need to bother any of you

I have now on my hands a malfunctioning Philips LCD TV, model 42PFL5322/10 with a 42" AUO 1366x768 LCD panel.

Symptoms: after turning set on, image shows up within about 4secs, then the display shuts down about 2secs later (with backlight turned off as well) and remains off till the next time the TV set is turned off and back on. After the display shuts down, sound still audible, and I can't seem to see anything if I shine a light on the screen.

I thought I'd be able to easily fix it as I did with the other monitor a year ago, but this time I can't see any obviously malfunctioning capacitor.
A certain capacitor has a radioactive-yellow tint on its top, but it looks to me like it was simply marked with a highlighting marker.
Also, some caps are mounted under enclosing metal plates which prohibit me from examining the caps properly. Looking from the side they look OK, but I might be wrong. The plates are a PITA to take off as they are soldered and also have some components externally stuck to them (to be used as a heatsink, I reckon).

I went ahead and downloaded the service manual, which unfortunately includes schemes for the SSB board only, with no schemes for neither the PSU, nor the inverter boards.

Some voltage and control lines I went through all showed voltages well within the range specified in the manual, these lines are labeled "+12v_disp", "+5v_standby", "+5V_SW", "+3V3_SW".

Also, control lines labeled "BL_ON_OFF" and "VDISP" show what appears to be a normal behaviour, meaning they go active about 4secs after I turn the set on, and remain active for as long as it is on, even though the display shuts down 2secs later.

I can order a replacement PSU on eBay, but I'm not sure if this is where the problem's at. From the control line behaviour I tend to believe the fault might be with the inverters.

Many thanks in advance for any advice/opinion.

I've attached pics of the set, various close ups, including of the capacitor with the radioactive-yellow marking.
Attached Images
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