Philips 52PFL5704D/F7 Sound and Backlight, No Video.

[tom66]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

Noise reduction on many sets I have found causes motion blurring, due to the filter used. I don't really recommend it unless an analog source you're using is extremely noisy, don't use it at all on digital sources (MPEG NR may help but not by much...)

[dejo87]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

Also, I believe the motion/scene blending problem on digital stations I described before was a firmware glitch when Noise Reduction is turned off, try turning it on and possibly off again to fix it, I just left it on.

[dejo87]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

Be sure you clean it again though, alcohol will work too

[dejo87]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

Mine did that too, been working fine since I took off the shield and thermal pads (take the thick gray pad and cut it down so it just barely covers the one small chip on the back of the tcon board, and slice it in about half thickness-wise) and zip tied a 120mm computer case fan to the tcon board area and plugged it into an empty spot on the power supply. Watch out for the tcon ribbons when you zip tie the fan down.

[sammy76]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

ok update time. after doing the acetone soak the tv worked great for about two weeks. then out of nowhere it showed the same symptoms when i tried turning it on. took apart again soaked in acetone replaced and worked great, for about an hour then vertical lines everywhere and when turned off and back on no pic. seems like a weak solder joint somewhere that breaks when heated up. so would the tcon cause the vertical lines?

[dejo87]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

TV has been working great for me now, not sure what caused the streaking issue.

[dejo87]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

Now for some reason when I tune the TV to digital cable channels through coax they have an interframe streaking effect where there is motion, as if the interpolation/120hz feature is broken. Doesn't happen on 1080p from my computer through HDMI 3. Opening and dismissing the menu makes the TV work properly. It only does this about 50% of the time.

Seems to be working better after being on for a few minutes, maybe the digital signal was weak? or maybe removing the heat shield is allowing interference to reach the TCON board on certain stations? or possibly a firmware problem I didn't notice before.

[kevinm34232]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

One of these just popped up on ebay

http://cgi.ebay.com/ws/eBayISAPI.dll...23#ht_64wt_934

[dejo87]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

I may try baking it if this doesn't work, anyone have any input on that? I've fixed an old 8800GT video card by baking it, three times... still works amazingly, using it right now. I'd put it in the oven for about 10 minutes at 385 degrees or so, I figured this board might be good with a little less time though.

[dejo87]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

I took the TCON board off again, wash, rinse, repeat, and left off the thermal pads and heat shield, except I took the small thick gray thermal pad and cut it down to be slightly smaller than the chip on the backside of the board, I wanted it to still have a pad on it since it doesn't get direct airflow and the gray pads seemed less likely to cause any kind of shorting issues since they felt less sticky and oily than the white pads. Cleaning the board causes it to work again every time, I checked to make sure that it was still acting up before removing the board and after unplugging and replugging the two cables that go to the main board. Works so far, fingers crossed. I don't know if the alcohol is making a temporary electrical connection somewhere, I wouldn't figure that though since it's 91% and evaporates really quickly. The TV has never stopped working on me until I turn it off and then turn it back on, but it's only been on for a max of about 3 hours.

[tibimakai]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

Maybe for some it's to late, something got damaged. Maybe I was lucky and repaired it in time.
I don't have that TV anymore, but I'm wondering from all that heat can't be that some capacitors(not sure if there are any) got damaged?

[dejo87]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

And it's still acting up, so much for the fan idea.

[dejo87]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

Hopefully the fan won't suffocate and be noisy with the back on, I think it will have enough clearance to work fine though.

[dejo87]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

I figured the fan would do more good than a heatsink, as it will cool everything (kind of), not only the chips, and it's cheaper and easier to put on a fan (depending on what you have on hand, but still easier even if you had everything you needed to do both.) I only had some Arctic Silver 5 on hand and there's no way I'm putting that on there (conductive), nor did I have any heatsinks that I could use (so many Socket A heatsinks lying around, being worthless.)

[tibimakai]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

I have found the same plastic layer, but on both sides of those thermal pad.
I have put thermal paste on every surface and installed a CPU heat sink on the shield and it was running like a champ.

[dejo87]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

So I got this TV and have this problem. I've cleaned the board in 91% alcohol and with a toothbrush twice, as it worked for awhile then on the next power on (I tried turning it back on after it being on for a couple of hours) and the screen would turn on for a split second and fade to black. The second time I took the TCON board off I looked at all 5 of the thermal pads more closely and noticed that it looked like whoever put together this TV only took off one side of the protective layer of each thermal pad. So the 3 gray pads had a thin plastic layer on one side, and the 2 white pads had a hard to remove paper? layer on one side. I recommend using a razor blade to get the paper off. I assume those aren't any kind of electrical insulator, I took them off and everything is fine. The TV still had this issue after doing that though, so I strapped a 120mm computer case fan and spliced the wires with a computer front panel (LED/power/reset) lead and hooked it into one of the two empty 4 pin connectors on the TV's power supply. Now the fan kicks on and off with the TV. I just got done doing this, I'll let you know if it makes any difference, the "heatsink" is nice and cool to the touch now though so if there is any problem still I doubt it will be heat related.

[cjacobs129]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

Thanks for all the posts on this subject. I pulled my board out and saw no immediate problems. Being that I am not a pro at do this I took it to a local repair shop who checked everything (for free even) and found no problems. They told me that often the problems is simply a poor connection somewhere. I put the board back in and made for certain that all connections were solid. The TV started right up. I really do appreciate all the advice on this subject, it sure helped me a lot. Thanks for taking the time to post!!

[sammy76]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

I got one of these off craigslist for free about 3 months ago figuring I'd replace a part and have a nice free tv. After pinpointing the problem to the tcon I figured I'd have to pay $125 to have it rebuilt, however I couldn't see any burn spots on the ic's so I tried rons solution.
Soaked it in acetone and cleaned the board thoroughly. Reinstalled it and amazingly it turned right on! Thank you Ron!!!
Also want to say that after my 7yo bumped into the tv it went from turning on with just a backlight to only clicking when plugged in but no response to the power button. Checked the power supply and saw one of the copper windings with a black plastic center was sitting higher than the rest. Apparently the solder on the legs had heated up and the part slid out some.
If anyone else has the dead except for clicking when plugged in problem I would recommend checking the rows of little copper wound capacitor things(not sure what they are) on the top right where the ssb cables plug in.

[RON_CET]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

Here's tip you can try on a repair for these T-Con board which more likely are very hard to find if one can and also most likely will never be available for part purchase from Philips or Sharp.Here's the method we have used.
(1) remove the metal shield from T-con
(2) remove the T-con from panel
(3) remove all four thermal heat transfer pads from T-con board
(4) we used tin pan that would hold T-con and use Acetone cleaner and pour
in pan to amount that would just cover top T-con let board sit for about 2/3 min.
(5) remove T-con and use tooth brush rub entire top and then bottom vigorously to clean both top and bottom.
(6) let dry for 30- 45 min reinstall T-con back to panel
(7) reinstall thermal heat transfer pads back from where previously remove
(8) reinstall ribbon connector and cables,reinstall metal shield
(9) turn on and bench test

Now our theory of whats happening is the oily residue after period of time from the thermal heat transfer pad is getting on the board and becoming some what of resistive coating and shunting the 3.3 volt source for the T-con

[kevinm34232]

Re: Philips 52PFL5704D/F7 Sound and Backlight, No Video.

It's the 2 large ICs that apparently go bad, there is a guy on ebay who repairs the boards, but it costs $150.

http://www.ebay.com/itm/Philips-52PF...#ht_426wt_1172