Samsung LN40A630M1FXZA no power

[PotShotScott]

Just grabbed a Samsung LN40A630M1FXZA. It looks to be in good shape. Got it all apart and don't see too much going on other than two disc capacitors that look a little warm. The front power LED just flashed about once a second. The previous owner claimed that the set would work after about 30 minutes or so for quite a while until it basically gave up the ghost. I've already tried heating the capacitors on the cold section of the PSU board and it didn't work. I did probe the power connectors and voltages appear to be there on some pins. ShopJimmy has a capacitor kit for this set. Is this a slam dunk to re-cap the PSU?

Attaching pics of the boards to the thread.

Why would I have 13VDC on two of the three pins listed... I *think* my VOM was making good contact. Does each capacitor feed a pin? I would think not...

[budm]

Re: Samsung LN40A630M1FXZA no power

You need to report the voltage readings of all the pin of the connector of the power supply board that goes to the main board when TV is OFF and when power switch is activated.
You must put down the pin name and follow by the Voltage reading, there are chart printed on the board indicating what each is, make sure to count the pins correctly, the exposed pins you can see on the top side of the board are the ODD number pins.
BTW, what is the power supply board number? BN44-?????

[PotShotScott]

Re: Samsung LN40A630M1FXZA no power

Thanks Budm. It's a BN44-00198A. Hard to use the power button since it's one of those touch sensor dudes. I have discovered a couple of things. I have the 13V and 5.3V that the TV calls for. However - something odd is happening every ~20 seconds (like stopwatch predictable). The voltages change on components. This board has a cooling fan. If I meter the fan line I get 9V constantly except for the complete loss of voltage every 20 seconds there. Really seems like a PSU problem at the moment. I'll grab ALL the pins and voltages in the morning.

[aaronwt6]

Re: Samsung LN40A630M1FXZA no power

This is going to be a main board issue. Most likely with capacitor C102 on the underside of the board. If you do a search on here for Samsung C102, you will find tons of info. If the previous owner continued to use it as described, the prolonged rebooting may have damaged the board even further but 99% of the time, changing that capacitor will remedy the issue.

I have repaired well over 1000 of these Pearl series boards now with excellent success.

[PotShotScott]

Re: Samsung LN40A630M1FXZA no power

Placed a 47uF 25v cap at C102. Same symptom. Thanks for the help.

[aaronwt6]

Re: Samsung LN40A630M1FXZA no power

Placed a 47uF 25v cap at C102. Same symptom. Thanks for the help.

Ok. Without the board in front of me to check in a known working TV, I couldn't really tell you where to go next but my belief based on your pictures and description of the power supply is still that the main board is at fault. Again, it's possible that continued use in the state the previous owner described may have damaged it beyond just changing the capacitor. I've seen some of those myself.

[aaronwt6]

Re: Samsung LN40A630M1FXZA no power

What type of cap did you use on that test? Make sure the polarity is correct. The line is on the + side of the one on the board.

[PotShotScott]

Re: Samsung LN40A630M1FXZA no power

I metered each side of the traces to ground and then (thought I) placed the cap accordingly. I used a simply electrolytic cap.

[aaronwt6]

Re: Samsung LN40A630M1FXZA no power

I'd be glad to take a look if you'd like to post a picture but that should have worked for you if it was the only issue.

[PotShotScott]

Re: Samsung LN40A630M1FXZA no power

Thanks - I buttoned it up a while ago and am taking it to the recycler. I wished I had more time but I do not plus boards are a little more than I want to spend online. Appreciate the help and the offer though!!