View Full Version : Philips 47PFL3603D/F7 no video


pac.attack76
11-02-2016, 02:34 PM
Chassis #LC8. 1U LA
Power Supply # 272217100571
bought this 47" lcd yesterday for $30 with the information that the set had to be turned on and off 2 or 3 times to get working which seemed to lean towards a flaky power button. Had nothing to do b with that as the same happened with the remote. Some times it would take a bit to get it to light up. Had it running for 30 minutes while updating my ps3 and the screen went black. Sound only. After that. Re powering would only quick flash and back off with still only audio. Tried again late last night and there was a rapid relay click a few times and a light hiss and now no power. Going to remove the power board today for some testing. What could I expect from this. Easy fix?

pac.attack76
11-02-2016, 05:43 PM
So far, this is what I've come up with. Two large caps circled in red have bulged. As a result, the fuse circled in red is blown. Caps are 450 WV 150 uf. Keep in mind, these pics are not from my set and my caps are swollen and deformed. I could see what looked like leakage as well. Does anyone have a couple of these they could spare?

CoogarXR
11-03-2016, 08:40 AM
You can't see it in that picture, but in the corner of that board there is a transformer for the CCFL inverter. Check the posts for cold solder joints. If that's not your problem, it will be eventually. I used to work on that model all the time, and when those solder joints fail, it will arc so bad, some times the board catches fire. I saw badly burned boards several times in that model and the 7603.

It's been a few years since I have worked on one, but I don't remember those big caps being a problem. Those plastic discs appear to bulge sometimes, but the caps themselves aren't bulged underneath. You can take that plastic disc off the top of the cap and look without hurting anything.

I know the Philips/Magnavox of that era did have bad caps, but it usually wasn't the big ones. It was usually the 1000uf, 2200uf, 220uf, etc, medium-sized ones.

Electronic M
11-03-2016, 01:18 PM
Might want to check the diode bridge that feeds those big 'spensive caps before you change them...

pac.attack76
11-03-2016, 01:19 PM
You can't see it in that picture, but in the corner of that board there is a transformer for the CCFL inverter. Check the posts for cold solder joints. If that's not your problem, it will be eventually. I used to work on that model all the time, and when those solder joints fail, it will arc so bad, some times the board catches fire. I saw badly burned boards several times in that model and the 7603.

It's been a few years since I have worked on one, but I don't remember those big caps being a problem. Those plastic discs appear to bulge sometimes, but the caps themselves aren't bulged underneath. You can take that plastic disc off the top of the cap and look without hurting anything.

I know the Philips/Magnavox of that era did have bad caps, but it usually wasn't the big ones. It was usually the 1000uf, 2200uf, 220uf, etc, medium-sized ones.

Unfortunately, those two large ones failed. Very low readings on both, bottom bulging as well as top. They even messed up the plastic rear panel for the tv but you can't see it with out close examination. One of v the c as rattles when you shake it. I'll check the transformer as well. All my other caps look good.

pac.attack76
11-03-2016, 01:21 PM
Might want to check the diode bridge that feeds those big 'spensive caps before you change them...

I believe it was checked but I'll find out.

pac.attack76
11-04-2016, 12:36 PM
Where's the diode bridge on this? Also, is the are mentioned earlier which is prone to arc in the top left corner?

Electronic M
11-04-2016, 02:15 PM
I believe the diode bridge is on the center heatsink...It is likely a 4 leg semiconductor (because who uses discreet diodes anymore?) that feeds gets it's input from the power cord (through some LC filters) and directly feeds those big lytic cans DC. If the bridge is shorted it will feed AC to the new cans and blow them quickly.

CoogarXR
11-04-2016, 02:36 PM
Where's the diode bridge on this? Also, is the are mentioned earlier which is prone to arc in the top left corner?

Yep that transformer circled is the one prone to cold solder joints and arcing.

I just happened to find a pic one online:

http://videokarma.org/attachment.php?attachmentid=192882&stc=1&d=1478284579

pac.attack76
11-05-2016, 12:17 AM
Does the bridge have to be de-soldered to test? The transformer connections look good. Found two caps for $8. Is that a good price? They appear to be a brand called Negetive. Never heard of them.

pac.attack76
11-17-2016, 01:06 AM
i want to check that bridge before i put new caps in. does it need to be pulled to test? what brands of caps are recommended? i dont want to use cheap caps and Radio Shack is out of the question.

miniman82
11-18-2016, 06:15 PM
Not usually, just use your DMM in diode test mode to go through the 4 internal diodes.

pac.attack76
11-20-2016, 11:56 AM
What reading should I get?

pac.attack76
11-25-2016, 07:51 PM
Not usually, just use your DMM in diode test mode to go through the 4 internal diodes.

What should they read if it's good?

Findm-Keepm
11-25-2016, 11:14 PM
With the DMM on the diode scale, you should place the negative lead (black lead) on the + lead of the bridge - that is where two cathodes are connected. Then place the red lead on one of the AC leads of the bridge (may be marked with a sinewave) - you should see the forward voltage drop of the diode, anywhere from 0.45V-0.7V. Then move the red lead from your DMM to the other AC lead on the bridge rectifier - and look for the same.

To test the other two diodes, place the red lead of your DMM on the negative lead (-) of the bridge - two Anodes are connected there. Then, alternate between the two AC leads of the bridge, again looking for the 0.45-0.7V voltage drop across the diodes. Any lower than 0.45V reading,and you've got a shorted diode in the bridge.

Youtube? https://www.youtube.com/watch?v=50Cwo3Of288

Hope this helps...

Celt
11-26-2016, 07:45 AM
Those big caps are marked as being made by Sahwah...and they do tend to fail early.

pac.attack76
12-27-2016, 06:04 PM
Ordered new caps and replaced blown fuse. Found power mosfet transistor shorted so now waiting on that. Everything else is ready to go.

pac.attack76
05-15-2017, 08:55 PM
For the record, I figured I'd mention that I finally got this set running a few days ago when I received my mosfet transistor. Great set for the $30 plus the couple dollars in parts.:thmbsp: