Philips 42PFL9703D/10 No picture

[Moreno83]

Just bought this tv with the symptoms that it does not turn on.
I asked the owner what happened and he said he heard a buzzing noise and the tv went to black. ( Sound and ambilight works ).

Removed the cover and i didn't see any visible damage. Removed the PS and checked the bottom and no damage there.
When i turn on the tv it stays on , front light flashes on start up but then stays on. Tv responds to the remote , going to standby etc but i don't get a picture on the screen. I don't see any backlight.

Been searching the forums but most problems for this model are " tv does not turn on" so replacing capacitor "2179 + 2165" won't do much i think.

Will post some pictures in a minute and do some measuring! If anyone has a tip for this particular model..i would appreciate it!

[CapLeaker]

Re: Philips 42PFL9703D/10 No picture

Backlight board fried or a bad ccfl is my guess.

[Moreno83]

Re: Philips 42PFL9703D/10 No picture

I replaced the caps on the PS , i now get a faint picture if i use a flashlight. So there is no backlight.

What can i test now?

[zomi]

Re: Philips 42PFL9703D/10 No picture

Check you inverter board/ Boards ( if you have 2)

Check if voltage is present there..

Sounds like blown inverter..

Also post picture of them so it is easer to advise you.

[Moreno83]

Re: Philips 42PFL9703D/10 No picture

Ok , i will check the inverter board. Requires to remove the complete back cover right? :o

Also , as seen on the pictures! When the TV is on i don't get any voltages on the 4 blue capacitors ( 22nF I think ). Is that correct?
I could remove those 4 and see if i get backlight back?

[newtothis]

Re: Philips 42PFL9703D/10 No picture

Ok first thing you need to do is make sure the PSU is getting the signal to start the backlights, Check all other voltages to make sure they are correct at the connector.

If all are present check fuses on Inv boards.

Then take it from there

[Moreno83]

Re: Philips 42PFL9703D/10 No picture

Argh haha , already removed all the cover

Will check the inverter board first.
What voltages do i need for the backlight? What i measured before removing everything was 25V for ambilight and 12V on a "spool". spool is right next to the blue capacitors.

[newtothis]

Re: Philips 42PFL9703D/10 No picture

~24v for backlights generally

Can you get a picture of the entire layout of the back of the TV please. One of each board inc invertors.. Plus close ups of connectors on boards

[Moreno83]

Re: Philips 42PFL9703D/10 No picture

These are the lamps and inverterboards. Dont see any burned lamps or spots.

Shall i rebuild the tv?

[Moreno83]

Re: Philips 42PFL9703D/10 No picture

Last picture is the main board connectors going to PS.

[Dang]

Re: Philips 42PFL9703D/10 No picture

Hi, I'm quite sure the inverter board is actually built into the main PSU board, I direct you to picture two on your first post, top left and across to the right a little. If you have a DMM you need to test as many components as you can in that area, so which one's are shorted or blown.

[Moreno83]

Re: Philips 42PFL9703D/10 No picture

Removed the 4 capacitors and now the tv works! Probably 1 or 2 lamps were asking to much power from the PS.

Will the tv last long without those 4 caps? How much voltage drop will the lights get with those 4 caps in place?

On the pic its clear to see that a few lamps are not on. Are these for sale?

[Moreno83]

Re: Philips 42PFL9703D/10 No picture

On first startup after removing the blue caps , the screen on the bottom was flickering. Can it be it needs more voltage to turn them all on?

[vr2yxt]

Re: Philips 42PFL9703D/10 No picture

I have the same problem. Replace the 4 capacitors (330pF 3KV) can only work for one or two days. Before no video, the back light will flash.

[vr2yxt]

Re: Philips 42PFL9703D/10 No picture

I have the same problem. Replace the 4 capacitors (330pF 3KV) can only work for one or two days. Before no video, the back light will flash.

I found a circuit for the high voltage inverter. The variable resister 3224 is for current adjust for 32"and 42" TV. Should I adjust it?

[CapLeaker]

Re: Philips 42PFL9703D/10 No picture

either that or "beefier" caps. In what condition are the CCFL's? If they are getting kind of pink hue, then they are toasted.

[vr2yxt]

Re: Philips 42PFL9703D/10 No picture

The TV are ocassionally work, so the CCFL and the active component should be fine. I intend to replace cap 2231, 2216 and 2247. These three caps are high voltage cap.

[vr2yxt]

Re: Philips 42PFL9703D/10 No picture

I have not replace the three high voltage caps but the TV is working now. It may be the new 4 caps are not stable in the beginning.