Philips 37PFL5603/D Feint flickering picture

[dicky96]

Hi guys, I got this Philips LCD TV here. I don't work on many LCDs, mostly LED so not had a lot of experience with them.

I actually repaired this about 18 months ago - it had a bad AS15, which I replaced and it has been fine until recently

Now it powers up, after several seconds the PSU makes a fizzing warbling noise (hard to describe) and I can see the CCFLs flkickering, then after some seconds it shuts down. It powers then back up again and the cycle repeats.

The voltages to the main board are OK (3.3V, 12V, -12V). All the caps are visibly OK.

Obviously there is some problem with the inverter or the CCFL lamp(s) but can I determine which without a spare inverter or lamp?

The PSU is a Delta DPS-279BP

best regards

[dicky96]

Hmm there are repair kits on ebay for this model TV which consist of four high voltage 6kV caps (they seem a bit steep at 15 euros!)
https://www.ebay.co.uk/itm/Reparatur...UAAOSwOVpXfSrB


Kondensator C327: 33pF x 6KV
Kondensator C329: 22pF x 6KV
Kondensator C330: 33pF x 6KV
Kondensator C333: 33pF x 6KV


Which would be the caps on the output of the inverter coil. You can't tell on my attached pic as the angle is wrong but the area of the PCB around two of those caps look like has been getting rather warm and is discoloured

It doesn't say on the repair kit what the symptom is that this fixes, but this may be my problem.

Does anyone know about those repair kits and what they are for?

Cheers

[R_J]

Have you removed the board and checked for poor solder connections on the transformer? It could be those caps are bad but they usually short, burn or crack open. It could also be a bad ccfl causing the issue or one of the transformer secondaries breaking down. If it is arcing, check it in a completely dark room, you "might" see the a slight corona arcing

[dicky96]

That was a good call R_J

One pin on the secondary of the transformer had a bad soldered joint, on my microscope it was clear to see there was a circular fracture all around the pin.

I used Solder braid and flux to clean all the soldered joints on the secondary and primary, then resoldered them

It works fine now, so thank you for the advice

best regards
Richard

[ivtec]

Originally Posted by dicky96

That was a good call R_J

One pin on the secondary of the transformer had a bad soldered joint, on my microscope it was clear to see there was a circular fracture all around the pin.

I used Solder braid and flux to clean all the soldered joints on the secondary and primary, then resoldered them

It works fine now, so thank you for the advice

best regards
Richard

dicky96, isn't this badcaps forum top notch ,and it's folks the best.