Phillips 50PF7521d/10 psu fault

[netdent]

Hi guys, went to pick this tv up to have a look at it for a friend, when powered up in his house went on to green led but no sign of life! I took it home removed the back then plugged it in and it worked! but I noticed a couple of domed caps on the psu, so I decided to replace these, acesss was difficult but managed to get at them by removing the 2 large resistors first, the caps were both 470uf 35 volts, not having the same value I replaced with 1000uf 35 volts (maybe a bad move?) anyway now when I power on it tries to power can hear the high volts etc but psu shuts off to 3 led blinks on the psu led, could it be these caps are now to high to do the job they were inteded to do? or coincidence, not able to find service manual, in pic 3 I have arrowed the 2 caps, the psu is PS-505-PNH or LJ44-00125A the panel is Samsung, any help would be great

thanks Ronnie

[tom66]

Re: Phillips 50PF7521d/10 psu fault

Did you use Maplin specials?

Looks like Lelon. Ugh. Probably was better with the bulged ones.

I believe this Samsung chassis has common problems with those two caps... there's a post somewhere about this.

[netdent]

Re: Phillips 50PF7521d/10 psu fault

Did you use Maplin specials?

Looks like Lelon. Ugh. Probably was better with the bulged ones.

I believe this Samsung chassis has common problems with those two caps... there's a post somewhere about this.

No they are recon 105 degree caps, will search for that thread, thanks

[retiredcaps]

Re: Phillips 50PF7521d/10 psu fault

the caps were both 470uf 35 volts, not having the same value I replaced with 1000uf 35 volts (maybe a bad move?)

In this thread tom66 finds a whole bunch of bad Capxon caps in a PSU and measures them with his ESR meter. He finds that some of the bad ones (bloated) measured 2x their capacitance.

https://www.badcaps.net/forum/showthread.php?t=17778

So moving up by 2x may have an effect on your Philips as well?

[netdent]

Re: Phillips 50PF7521d/10 psu fault

In this thread tom66 finds a whole bunch of bad Capxon caps in a PSU and measures them with his ESR meter. He finds that some of the bad ones (bloated) measured 2x their capacitance.

https://www.badcaps.net/forum/showthread.php?t=17778

So moving up by 2x may have an effect on your Philips as well?

Thanks for that will order up some proper caps to rule that out

[tom66]

Re: Phillips 50PF7521d/10 psu fault

In this thread tom66 finds a whole bunch of bad Capxon caps in a PSU and measures them with his ESR meter. He finds that some of the bad ones (bloated) measured 2x their capacitance.

https://www.badcaps.net/forum/showthread.php?t=17778

So moving up by 2x may have an effect on your Philips as well?

Take note however the PSU was still working with these.

Increasing the capacitance probably isn't the major problem, although it may change the filter characteristics (if it has an LC filter), which in rare cases can increase ripple. Then again, I didn't design the supply, so there could be things like rise time limitations playing into the problem (power supply might be shutting down if voltage does not reach nominal in some amount of time, which is longer with 2x capacitance.) Just speculating...

[netdent]

Re: Phillips 50PF7521d/10 psu fault

Take note however the PSU was still working with these.

Increasing the capacitance probably isn't the major problem, although it may change the filter characteristics (if it has an LC filter), which in rare cases can increase ripple. Then again, I didn't design the supply, so there could be things like rise time limitations playing into the problem (power supply might be shutting down if voltage does not reach nominal in some amount of time, which is longer with 2x capacitance.) Just speculating...

Ok thanks, now working, changed the caps for 2 rubycon 105 degrees, so far so good, now on soak test

cheers guys

[Johnboy78]

Re: Phillips 50PF7521d/10 psu fault

Sorry to drag up an old post but ive just got this tv, when plugged in the green light came up and i could hear relays clicking a few times but not much else, no pic or sound. Ive taken it apart and replaced 2 caps that were domed....but also on the board there is 2 large 130c 63v caps which are gold in colour and these are really bulged so need replacing, does anyone think it could be those 2 causing the problem? im struggling to find them anywhere for sale.

Is it also worth trying to unplug the audio board which i read in another post about this tv and did the trick? any help would be good. thanks

[Alfa12]

Re: Phillips 50PF7521d/10 psu fault

My Philips Plasma 50PF9631D/10 had a bad Y-sus which I replaced.
After checking all voltages the only problem is that the Vs voltage cannot be set lower than 206 V with the pot.
On the panel label is indicated 198V. I changed numerous suspicious caps already with no effect.
The screen image is perfect and everything works, but won't close the cover until the voltage is correct again.
Does anybody has experience with this problem?

[tom66]

Re: Phillips 50PF7521d/10 psu fault

It is odd that you cannot set it lower, but in my experience most 50" Samsung panels use Vs in the 205 to 210V range. I am working on a similar generation now with 207V Vs. Are you definitely reading off Vs voltage correctly?

[Alfa12]

Re: Phillips 50PF7521d/10 psu fault

Correct.
All plasma's (newer than 2007) I repaired thus far have normal readings of 207 V.
This one is different, I don't know why. I am still guessing and replacing parts on this psu and still no change.