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

[tibimakai]

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

Sorry about that, I have just realized what you were referring to.

[tom66]

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

Great. Now I know. Do you see CN2 with lots of little silver dots next to it, below "RUNTK"? Connect the ground probe of your scope to the brown copper exposed to the LEFT of these. Then carefully touch and hot the probe on the dot. Press AUTO on the scope (cheating, but it will work for now.) Do you see anything? If so, the main board is probably sending data but the T-con isn't listening.

If you don't get anything, try the a few other dots until you get something. But if you still don't get anything, the main board is faulty.

[kevinm34232]

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

Also you have 12v on at the fuse but no voltage at IC201 right? So it would appear that something on the T-Con is shorted..

[tibimakai]

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

Not shorted, but bad. What that could be, that is the question.

[tibimakai]

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

I don't know Tom, what is going on, but I can't see any sinuses or square waives. There is something going on, but it's all concentrated along the horizontal line. No matter what kind of adjustment I'm doing on the scope, can't make that signal to show bigger.
The voltage measured is 14.4V-15.2V on the scope.

[tom66]

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

That would mean the main board isn't sending a signal some how. You pressed AUTO when you probe one of them?

[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.

[kevinm34232]

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

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

[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?

[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.

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.

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.

[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.

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

[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.

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.

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

[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.

[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.

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