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

[tibimakai]

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

The good one, is running hot too?
Those little electrolytic capacitors never need replacing? Since the board it's running so hot, these capacitors should dry out too, no?

[kevinm34232]

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

It's got to be something on the T-Con board. It is strange, the customer I bought mine from had intermittent picture too, and then finally it went out completely. I replaced the bad fuse (which I may have blown by accident with a slip, not sure) and it came back on for 2 days then went out again, and fuse was still good. A new T-Con board has been going good for weeks now. Maybe it is something close to the fuse that temporarily fixed it when heated up in that location...

Also when no picture, no voltage at that IC201 when 12v is present at the fuse, that has to be a clue for something...

[tibimakai]

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

Most likely you are right about it. I will try it out when I have a little bit of time.
Do you think since with a fan it's running can be a bad joint too?
All these are on/from the power supply and not the T-con?

[tom66]

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

I doubt it... I'll bet you've got a thermally intermittent cap or solder joint on the board somewhere. You could use your scope to check the power supply ripple on the rails. AC coupling, 20mV div, 100ms div, it should not exceed one division maybe two at most.

[tibimakai]

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

I have left it all afternoon yesterday running with the fan and it worked.
Turned it on and off and it still worked.
My next step is to install some heat sink to the T-con shield.
Anybody knows if that heat transfer pad can deteriorate in time?
Maybe just that has to be replaced?

[Scuuba Steeve]

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

Hi everyone new to the board. I am having the same problem with my Philips 52". TV was working perfect i turned it off and the next day when i turned it on no picture just sound. I called the repair man he ordered a part and it did not fix it so he said it had to be the TCON board but he can't find it. So i let the TV sit for about a week. I plugged it back in and it worked fine. I left it on for 2 days it worked perfect then i turned it off and now no picture just sound. I am so glad i found the forum so i can get a little help and to try to help others with this problem.

[tibimakai]

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

I have done that already. Thanks for the advice though.
I have a feeling that it's heat related.

[tom66]

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

Try cleaning the cables with a little isopropyl alcohol or contact cleaner.

[tibimakai]

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

Initially when I've got the TV were crocked and not inserted all the way in.
After re-seating them correctly, the TV fired right up and I thought that I have fixed the TV.
After a couple of hours of run time, I have turned it off(wanted to do a firmware upgrade) and after I have turned it on, the video signal it was gone. For a couple of days I was doing some measurements and the ribbon cables were removed from the T-con. After reinserting them last night, the TV fired back up again. It seems, that every time I'm reinstalling the panel ribbon cables the TV turns on again.
Something weird it's going on here.

[kevinm34232]

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

Do you think then the ribbons weren't fully seated before?

[tibimakai]

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

I have left it overnight(9-00PM-6:00AM) with a fan pointed upwards at the TV(TV vertically with removed back cover and the fan-Tornado- pointed up) and in the morning it was still running.
I will install some heatsink and see how it will work. I think that I have some PC CPU heatsink around the house and see what happens with that.
The mainboard processor it gets pretty hot too.

[kevinm34232]

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

Yes mine run hot too, I also noticed that too and put on the shield just while I was testing the boards. It would probably be a good idea to put some good aluminum heat sinks where the sponges are.

[tibimakai]

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

Here are the pictures when it wasn't working(no video signal either).

[tibimakai]

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

I have reconnected the panel ribbons and the TV started right up.
Explain this one.
I have noticed that all the processors on the T-con are running very hot. I have reinstalled the shield to take over from that heat, but it doesn't seem enough.
Now I have put a fan on top of it and let it run and see if it will fail this way.
I took some pictures with the scope screen. I will post it in a bit.
The VDO(if it's a VDO) measures 3.2V/0.003V/2.5V now when is working.

[tibimakai]

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

I have measured the first pad from the side of the board, but it comes out a .ref file.
I can't view it or attach it here.

[tom66]

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

Set it to 1X and go to the Ch1 menu and select 1X too. Take a screenshot of your scope image - try STORAGE->BITMAP and save to USB.

[tibimakai]

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

Not sure to tell you the truth.
Today I have measured those taps with the DMM and I was getting only 1.1V-1.2V, then I realized that I have a switch on the probe(1x, 10x) and most likely I was on the 10x setting.
Could you please tell me how would you set yours(our scopes are probaly identical scopes) step by step as you turn it on?

[tom66]

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

Yes and then bumped up the voltage to 20V and I was adjusting the time from min to max.

You want to lower it to possibly as little as 100mV/div and 100ms/div but you still see nothing? Scope is definitely RUNNING, not waiting for trigger?

[kevinm34232]

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

Sorry I don't have a scope to compare readings for you...

[tibimakai]

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

Yes and then bumped up the voltage to 20V and I was adjusting the time from min to max.