Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

[Bafury]

Hey guys.. i have a 42pfl5332d/37 Philips that's playing tricks on me.. when i press the power button from either the remote or from the tv, the backlight comes on...assuming everything is okay. Tired of watching tv, i then turn the power off. five minutes later, I turn the set back on, but there no backlight. I just can't figure it out, and was hoping you guys can guide me in the right direction. I provided a link to my video showing the symptoms.. Also, if someone can show me the right setting on the multimeter for testing would be helpful.

VIDEO LINK

http://youtu.be/uyYpv8wuHg8

[philliesfan30m]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

you have it on the right setting for testing anything under 200 dc volts. your slave inverter is working intermittently i am assuming. when it does work did you get the 24 volts on the slave? the 1 on the right looking at it from the back.

[philliesfan30m]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

i'm just here learning myself but i would say it might be a bad solder joint if it is intermittent. you can disconnect the connector for the slave board at the power board and power it up and check to see if you have voltage on the pins where the connector attaches. if you have a hairdryer you could heat up the slave board and see if anything changes.

[Bafury]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

Thanks for replying philliesfan30m

Yes. When the backlight does come on, the first five pins read 24 on the slave inverter, as well as where it's connected on the power supply board.

[tom66]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

And when it fails to come on, is 24V present or not?

[philliesfan30m]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

this thread mentions your tv as being 1 of the possible tv that may have the same problem.

https://www.badcaps.net/forum/showth...2pfl5332d%2F37

check the ic with 26 legs located to the left of the caps in your pic of the master inverter board to see if it has any tiny pin holes or the legs are broken i can't really tell my looking at it in the pic but this problem doesn't state it is intermittent but check to make sure

[philliesfan30m]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

tom is here he will be able to assist you better than i will!

[philliesfan30m]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

he said in his video that he doesn't have 24v on the slave when the backlights don't come on tom

[Bafury]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

Hey Tom
The first five pins read 24 when the backlight does not come on as well

philliesfan30m

i checked the 26 pin ic, but it seems okay

[philliesfan30m]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

in that pic you just took the connector on the master board is it just the pic or does it look like the 6th pin from the bottom got hot at 1 time?

[Bafury]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

yeah.. i made a mistake and touched it with the multimeter point, and it made a spark, but the backlight issue was still present even before i did that..

[freakaftr8]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

Either you have a fault with dry solder joints on the inverter transformers or a circuit within the inverter is not working properly. I believe the BL_ON controls the 24v to the inverters so the power supply is doing its job. You could check the ballast connectors for bad contacts sometimes you will see an arc or a burn spot within the output connectors to the bulbs. If all the inverter transformers are not within spec of each other the inverter will fail to start. Do you have voltage at BL_ON when the tv fails to light up?

[freakaftr8]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

Also those 35v 470mfd ccapacitors on the slave and master inverters in the lg philips tv's have been known to cause issues. Can't tell from the pics but do they look domed at the top, leaky? I would replace them first.

Also reading your post when you're back light does not turn on do you still have audio? Can you take a flashlight and look into the screen and see that the TV is still working?

[tom66]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

BL ON does not switch 24V on most TVs, 24V is active before BL ON turns on inverters.

[Bafury]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

freakaftr8,
thanks for replying, but you lost me at BL_ON, but i did check the capacitors on the inverters , and they look okay.. Can you explain what and where the BL_ON is?

[freakaftr8]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

Gotta listen to Tom on this one. 24 v should always be there BL_ON is the reference to turn on the inverters. This pin should be labeled on power supply output to inverters.

[Bafury]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

The power supply board doesn't have any labels at all.. Or maybe i don't understand.. In any case, i get 24v from both master and slave when the backlight decides to come on or not. That test was done from where the inverter plug into the power board.. The only difference is that the slave only gives me 24v in the first five pins, and the rest of the pins reads 00.0. thanks guys for responding.

[freakaftr8]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

I believe the other pins that Give you 0 are grounds. But there should be a reference pin for backlights to turn on there somewhere. Ohm the pins that give you 0 against ground. One of those that have no power but does not ground out may be your backlight on pin. That should be like 3.3v thereabouts
Best to measure with your meter set to diode range so you can take black lead and use a ground point on the TV red lead on each of those pins that give you 0 see if your meter Beeps

[freakaftr8]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

either Pin 11 or pin 12 on the right-hand board should be your backlight on signal

[Bafury]

Re: Philips 42pfl5332d/37 blacklight headaches... WATCH VIDEO

here is a picture of the test results..The test was done while the blacklight was on.