dreaded Philips power supply

[ajshoe]

Have a Philips 46PFL5505 TV that won't power up. Originally would after unplugging set and waiting - power up ok. got worse and now won't power up. 5V is not there - When power is applied - 5V is there for a second and then trickles down to -. I have bench tested power supply. same scenerio - 5V comes up then goes down. Have checked everything on PWB - can't find problem. Does anyone have any experience with these Power supplies ?? It is a UPBPSPDEL004. Also a UPBPSPDEL003 is the same PWB. Any suggestion would help - can't seem to find any of these boards available for purchase.

tests - have 0V at +5.3V C0N2 pin 9
have 600V @ C800 & C808 (across them)
checked all optos
thought T901 was bad - but now think its freq circuit before that, this circuit turns on transformer.

[budm]

Re: dreaded Philips power supply

https://www.badcaps.net/forum/attach...2&d=1468865850
Did you check those two electrolytics cap in the top left section where the 5VSTBY circuit is? Did you check the diodes D952, ZD951 in the cold side of the 5VSTBY.
You can also heat up those two caps with hair dryer to see if the 5VSTBY will come up and stay up?

[ajshoe]

Re: dreaded Philips power supply

Have checked all diodes and zeners. r u talking about caps C800 & C808 under heatsink ?

[budm]

Re: dreaded Philips power supply

Top left corner of your pictures, you can see two small lytics caps by the small transformer and the SMPS IC for the STBY..
https://www.badcaps.net/forum/attach...2&d=1468865850
Pictures are not clear enough to read the designators.

[ajshoe]

Re: dreaded Philips power supply

you must mean C906 & C912 ??

applied heat to area you posted - 5V did come on. put a 2k resistor on 5V to ground - 5V fluctuated a little but stayed on. not sure if caps, transformer, or smps made it turn on. checked caps - they tested good on ESR, transformer seems good also.

[ajshoe]

Re: dreaded Philips power supply

If anybody has a UPBPSPDEL003 or UPBPSPDEL004 for sale - please PM me. Don't think these PWB are repairable. thanks

[budm]

Re: dreaded Philips power supply

Why not trying replacing those two caps?

[ajshoe]

Re: dreaded Philips power supply

Just a follow up on this PWB - sent it to PTS and they repaired it. I spent many hours on this PWB and never got +5V standby to stay on. These PWB are tricky to say the least. Thanks PTS !

[R_J]

Re: dreaded Philips power supply

I would change the ic901 dnp005, also check the voltage on zd901 (UDZ7V5B-7), should be around 7.5 volts (use hot ground not chassis), if its there, check Q902 (transistor),q903 & q9o4(fets)

[ajshoe]

Re: dreaded Philips power supply

wish I had that info earlier !! I did replace zd901 and 2 other diodes. I had a feeling that IC901 was bad. I hope I don't see another one of these sets. does have a decent pic but doesn't warrant working on another one !

[R_J]

Re: dreaded Philips power supply

Does this manual help? I think its the same power supply, not sure if you had it or not.