Samsung PN58A55081FXZA pops main fuses

[LameCooter]

Re: Samsung PN58A55081FXZA pops main fuses

@vinceroger69: I had the outer one bent forward but just to be sure I insulated it and the problem was still there.
BUT
I went back to square one and was testing all the components for shorts and it turns out the second MOSFET is now shorted. Wasn't before but it is now.... go figure. Anyhoo, I have ordered another one and we'll see what happens then.


Thanks for all the help.

[LameCooter]

Re: Samsung PN58A55081FXZA pops main fuses

I replaced the bad FET but the unit will still not go into standby. The relay clicks over and over. I want to test this unit isolated but I want to be sure what pins to short to do this. Do I short direct or use a resistor?

Thanks

Greg

[LameCooter]

Re: Samsung PN58A55081FXZA pops main fuses

any help appreciated.

[LameCooter]

Re: Samsung PN58A55081FXZA pops main fuses

I tested the PS without the mainboard attached by shorting PS_ON on the connector to the logic board and the relay still pops over and over. I did have my test light bulb jig installed which has only a 125w bulb, but I figure with all other boards disconnected the wattage of the bulb was a non issue.

So what I have is a bn44-00183a SMPS that will not go into standby. Using the schematics I am testing each individual component for shorts or irregular behavior.

My question is this: What parts of the board are only used to put the unit in standby? It seems to me that I can focus my attention on that part.

Any tips of how to troubleshoot this are appreciated.

Thanks

[LameCooter]

Re: Samsung PN58A55081FXZA pops main fuses

bump

[LameCooter]

Re: Samsung PN58A55081FXZA pops main fuses

I really don't know what to check next. I checked every component on the PFC schematic for shorts.
I also checked the following for shorts:
ICB804, ICQ802, QS801, QS802, QX801, QX802, ICM802, DS851-DS854, ICX852, ICX854, CP817S, CP818S, ICS801, ICX801.

Basically I checked every diode and transistor I could see and if it looked suspicious I would pull it and test again.

All I get it this: With PS plugged and no connectors connected -or- only logic board connected I get 3.3V on the STBY port on CN801 (to mainboard) and something higher on PS_ON.. Dont recall at the moment but a little higher.

If I attach Mainboard -OR- short PS_ON on Mainboard connector I get rapid relay clicks on RLQ802S.

Also it should be noted I am using a light bulb jig and it flashes in unison with the relay.

What am I missing?
Thanks

[tom66]

Re: Samsung PN58A55081FXZA pops main fuses

It is normal for some PSUs to rapidly cycle with a lightbulb in series. You may have to use a bigger lightbulb.

[LameCooter]

Re: Samsung PN58A55081FXZA pops main fuses

Thanks for the reply.

I am using a 125W bulb. What would you suggest? 2 100W in series?

Thanks
Greg

[TadTV]

Re: Samsung PN58A55081FXZA pops main fuses

Have you had any luck? Where did you find the thermistors? Part number? Also do you have more pages of the schematic for bn44 00183a power supply. I've got a 58A550 that wont power up as well. One of the thermistors has no reading. Thanks

[LameCooter]

Re: Samsung PN58A55081FXZA pops main fuses

Still not working but I put it aside to finish making my isolation transformer... I feel like I'm going to need to run power through it to find the short.

The thermistor I used is B57364S100M from Mouser. Seems to do the trick.

Good Luck

[TadTV]

Re: Samsung PN58A55081FXZA pops main fuses

Thanks LameCooter for the part #. I got it through Digikey because they had cheaper shipping for such a tiny part.
I put in the thermistor LameCooter mentioned and the TV powered right up! It was a bitch to get it into the posts that were soldered into the board but after an hour I got it. I ended up desoldering the posts off the board and then cleaning out the posts and then sticking the posts back onto the board and then inserting the thermistor leads into the post sand then soldering the both (post and lead) to the board from the under side and then clipping off excess leads. What a pain. Not sure why they put the thermistors into posts and not just the board. Maybe something to do with heat?

Anyhow, it all works but as others have mentioned, this just might get me back to hearing the clicking no start issue in a few weeks. As I read on another forum, The thermistor going out was just a indicator to a deeper issue. Lets hope time will tell. For the next month though I will not attempt to hang it back up above the fireplace- its just too heavy if I have to work on it again.

[LameCooter]

Re: Samsung PN58A55081FXZA pops main fuses

Well I bought another PS on ebay that look ins pretty decent shape. Should work out of the box but if not I have a board I can scavenge spare parts from.

My question: Other than adjusting the Vs and Va to spec, are there any other adjustments I need to make?

Thx

[tom66]

Re: Samsung PN58A55081FXZA pops main fuses

That should be all, as long as you don't replace any other boards.

[Lloyd6202]

Re: Samsung PN58A55081FXZA pops main fuses

Thermistors burned up on my set but also damged the two relays beside it RLQ801S i need to find these relays but no part number