Samsung LE32B455 intermittent loss of power

[PowerAmpFreak]

Hello all,
According to owner, it would sometimes appear all dead. Not even the standby light is on. Can't get the fault to show up, and a check of standby supply didn't give any clues.
Is there any known issues with this supply?
All caps looks good,

[PowerAmpFreak]

Re: Samsung LE32B455 intermittent loss of power

Check the attached picture if your memory can come up with something
I touched up the soldering on power components, replaced the secondary caps just to be sure they're ok. But this SMPS has worked every time for me, but the customer is sure it won't.
Over time it was harder and harder to start it up (like typical cap problem).

[tom66]

Re: Samsung LE32B455 intermittent loss of power

Replace the startup cap if encounters further issues.

[mtoivanen]

Re: Samsung LE32B455 intermittent loss of power

Hi! I have same TV, with same problem. It's totally dead, standby line shows up 0.2V. Any clue what could be broken, both of fuses are good? PSU model is BN44-00261B.

[CapLeaker]

Re: Samsung LE32B455 intermittent loss of power

Check if you have power on the primary filter cap

[mtoivanen]

Re: Samsung LE32B455 intermittent loss of power

Check if you have power on the primary filter cap

Checked, there is power going to primary filter cap But nothing is coming out from PSU

[CapLeaker]

Re: Samsung LE32B455 intermittent loss of power

O.k. you have power to the big 400V filter cap, that's good. Now look if you are getting 5V on the 5V rail. The 5V should be always on, with the TV on or off. If there is nothing there, check the diode and caps right after the transformer (see schematic, p1 top right).

[tom66]

Re: Samsung LE32B455 intermittent loss of power

Also check voltage across Vcc cap for PSU controller.