Samsung PN50A5550P3F Power Supply Board BN44-00222A

[aaronwt6]

http://www.shopjimmy.com/samsung-bn4...upply-unit.htm

I've got one of these power supplies here from an eBay customer and am trying to track down the issue. I repaired the main board for the TV and was notified that the TV was still not working properly. The TV originally was having the typical rebooting issue related to the failure of C102 on the main board. I repair these often and offer a service on eBay for them.

For testing, I have only a LN40A630 to check the main boards for the LCDs and an PN58A550 for the plasma boards. These boards have auto LVDS so you can check them all in one model.

Now, on to the customer's issue with the power supply. I offered to look at it out of kindness after the main board repair failed to get the TV going. I'm unable to live test it since my plasma on hand is a 58". I've dealt with plenty of these supplies before and typically, they either have a couple failed caps and sometimes that's followed by blown diodes, fuses and/or other components. This particular board seems to have none of the above and all the solder joints look fine. It has standby voltage, but when I ground the PS-ON pin I get no relay click at all.

Has anyone experienced this symptom on the BN44-00222A? I'm at work right now and won't be able to troubleshoot further until this evening but wanted to get the ball rolling. I've read all threads I can find here as well as several other sites but I cannot find anyone else that had 5V but no relay click. Once again, I can only bench test this board and have no TV on hand for it.

Any help is greatly appreciated as always.

Thanks,

Aaron

[aaronwt6]

Re: Samsung PN50A5550P3F Power Supply Board BN44-00222A

After hours of scouring this board, I have it resolved. It was a cold solder joint on one of the relays itself. Found it had no continuity then saw the crack under a magnifying glass. I spent more time on it than it's worth but such is life. It's on the way back to the customer and I'm awaiting the update when it arrives.

[dick_barton]

Re: Samsung PN50A5550P3F Power Supply Board BN44-00222A

It may have taken more time than you wished it to, but well done in finding the fault.

[aaronwt6]

Re: Samsung PN50A5550P3F Power Supply Board BN44-00222A

It may have taken more time than you wished it to, but well done in finding the fault.

Thanks. I was really happy in the end and will know for the next time. I did do one thing I've never tried in order to troubleshoot this board. I hooked the power supply up to a main board with speakers and a Blu-ray attached to let it run for a bit after touching up the solder on a bunch of components. I've done similar things on some LCDs with the screen not working but never with the boards completely out of the TV like this. It was quite funny listening to a movie play via two circuit boards, a wiring harness, and a pair of speakers.

[Spector]

Re: Samsung PN50A5550P3F Power Supply Board BN44-00222A

I'm just asking out of curiosity, but what was the problem with the main board originally?

[tvtimmy]

Re: Samsung PN50A5550P3F Power Supply Board BN44-00222A

The c102 fault will cause re-booting, greenish screen, and a screeching sound coming from the speakers. I also had one that turned on normally but when you tried an input, such as HDMI, it would go crazy. I replaced c102 with a new 47uf 10 volt tantalum capacitor and it was fixed, and still is 2 years later.