Schematic needed for Samsung Power Supply BN44-00502A

[DXseekerMO]

Hello everyone!

I'm needing a schematic for a Samsung Power Supply part# BN44-00502A. Can anyone help me with this? I checked the usual suspects, Electrotanya etc. and have had no luck.

In particular I need to know if capacitors CP818 and CP819 are the same value?

CP819 appears OK (at least not short anyhow), but CP818 was blown to smithereens. There's no getting a value from that one! It looks like it even caught fire as there was a smoke trail and soot on the board from that cap up!

Thanks!

[SMDFlea]

Re: Schematic needed for Samsung Power Supply BN44-00502A

There`s no schematic. Found a repair kit on ebay, if the cap values in the picture are the real values then they are the same https://www.ebay.com/itm/154313170055 ,its worth checking the other parts listed in that kit to find what made that cap go up in smoke

[DXseekerMO]

Re: Schematic needed for Samsung Power Supply BN44-00502A

There`s no schematic. Found a repair kit on ebay, if the cap values in the picture are the real values then they are the same https://www.ebay.com/itm/154313170055 ,its worth checking the other parts listed in that kit to find what made that cap go up in smoke

Thank you for the reply and the link SMDflea! I didn't see that listing, but I bought basically the same kit on Ebay from a company 17 miles away from me, minus those caps.

Of the components that come with this kit here's what I found on the board:

Fuse FP801S was open

The Rectifier Diode BD801S had good diode readings (about .5) on three terminals and did not reverse bias on any of them, but from the - to + terminal the reading was .950, a bit too high so it will be replaced.

QP801S was shorted across all three legs and will be replaced.

Diodes DP802 and 803 tested ok.

Diode DP808 did not reverse bias and tested at .420, but will be replaced for safety's sake since it was closest to all the carnage.

Capacitor CP819 tests OK. Capacitor CP818 was trash. Both will be replaced with ones I have in-stock.

Diode D9102 tests ok

Resistor RQ951 tests short in-circuit. Diode DQ851 also tests short and does reverse bias in-circuit, but both are in-circuit with transformer TM801S. As I'm installing the kit I'll probably de-solder and lift one leg of each to verify.

I'll likely replace ICP801S due to the carnage near QP801S, and because legs 5 and 6 test short to each other.

I'm not sure if I will replace IC9101 unless there's an issue with the backlights after the repair. I'm pretty sure this is the LED Driver IC.

My only remaining question: On the blue plastic caps does it matter in which direction they are installed? They aren't polarized like an electrolytic are, correct?

Here's a link to the kit I bought: https://www.ebay.com/itm/312222006412

[SMDFlea]

Re: Schematic needed for Samsung Power Supply BN44-00502A

The caps are ceramic and non polarised

[DXseekerMO]

Re: Schematic needed for Samsung Power Supply BN44-00502A

The caps are ceramic and non polarised

Thank you much!

[SMDFlea]

Re: Schematic needed for Samsung Power Supply BN44-00502A

You`re welcome. Let us know in a follow up post if the repair is successful

[DXseekerMO]

Re: Schematic needed for Samsung Power Supply BN44-00502A

You`re welcome. Let us know in a follow up post if the repair is successful

Will do!

[DXseekerMO]

Re: Schematic needed for Samsung Power Supply BN44-00502A

You`re welcome. Let us know in a follow up post if the repair is successful

So the kit came in today. Upon inspection the resistor they sent for position RQ951 is blue-bodied, 2ohm 1% tolerance and almost too long for the holes in-place. The one in-place upon the board is green bodied and 2ohm 5% tolerance. Can anyone tell me if this is a problem?

Thanks!

[DXseekerMO]

Re: Schematic needed for Samsung Power Supply BN44-00502A

Ok, I installed BD801S, QP801S, DP808 and CP818 and 819...and I have a result.....kinda.

Immediately after installing the PSU into the TV I turned it on and it looked good, so I went in to the other room to get an antenna lead. When I came back the TV was in the process of re-starting on it's own. It then stayed on for about 10 minutes.

The next thing I know I hear a faint but rapid "clicking" noise. The TV shut off and tried to re-start but turned right off. The stand-by light turned on solid, blinked 2 times, came back on solid, repeat.

This is a very similar scenario to the PN51F8500AFXZA I just worked on with a bad PFC Mosfet. It turned on but there was a clicking noise coming from the PSU. I re-did the solder joints and it worked OK for about a week.

I started thinking about common denominators between the 2 TVs. Both "repairs" were done with an old soldering iron tip that wasn't in very good shape at all. This has me wondering if the solder joints are contaminated.

So this may be a dumb question.....but here goes. Could contaminated solder joints be causing the problem? On the surface they look good, but I can't see inside the joint to tell. I tried to keep the iron's tip as clean as possible, and I used flux too so I thought the flux would help keep the joints clean.

Boy I feel full of stupid questions a lot here lately, but at least the TV turned on and the screen is good!

[DXseekerMO]

Re: Schematic needed for Samsung Power Supply BN44-00502A

Well guys I think I may have figured this out.

I turned the TV back on to see if I could ascertain the exact location of the clicking noise. The TV faulted again, except this time I heard a low-volume "pop" on the Power Supply and cut the AC power immediately.

As I got to thinking about it, the soft "pop" I heard sounded a lot to me like an arc. I removed the PS from the TV for inspection.

What I found was flux on the PFC IC that looked like it had an arc go through it. Upon further inspection I found several spots near the components I replaced that still had flux near them.

I spent the next 25 minutes carefully inspecting the board and cleaning up any flux I found. After I was satisfied I got it all I installed the PS back in to the TV, fired it up and it's been running without fault for the past 20 minutes. As soon as I turned it on there was a noticeable difference in the picture quality.

So the apparent moral of this story....after component replacement make sure you clean the flux out of the board, or your TV might get fluxed up!

I'm going to leave it on for the next couple hours and see what happens. Tomorrow I'm going to pull the Power Supply out of the F8500 and check it to see if it's fluxed up too.

I'll update the post again tomorrow and let everyone know if it's still alive.

[DXseekerMO]

Re: Schematic needed for Samsung Power Supply BN44-00502A

You`re welcome. Let us know in a follow up post if the repair is successful

Well since this morning the TV was on for 8hrs without any problems. I turned it off to go to the store, came back and turned it on again, it turned on just fine!

As far as I can tell this is a successful repair. On top of that this is my FIRST successful diagnosis and repair on any power supply without having to ask a bunch of noobie dumb questions (just a couple) and frustrate the socks off those who tried to helped me. It's a red-letter day for me and TV repair, and there's no way I could have come this far without all the help I've received since joining BADCAPS.NET!

My sincere thanks to everyone who's helped me get this far, indeed I am grateful to all of you and TOPCAT for providing the site.

CHEERS!

[Zaman Kay]

Re: Schematic needed for Samsung Power Supply BN44-00502A

Hello TS,

I have a same board like u from samsung ua40ea5600r. My problem is led backlight damage. So i change to a new backlight. But the new backlight seem to get a low volt because it not so bright and keep flickering. I check the led driver output and its not get the real output. It is the ic 9101 problem? Because you mention it was the led driver

[therealovy77]

Re: Schematic needed for Samsung Power Supply BN44-00502A

Hello from Romania. I have problems with the same power supply in an UE40ES5800. When I apply power, i hear a buzzing noise in power supply, and the stand-up led blinks twice, and then stop buzzing (with solid red led). After that, this cycle repeats....
The LEDs connector gets 5-6 volts on left and ZERO on right, and goes down to zero both after.
I think the power supply is broken, but i ask you for help.
What voltage must be on led connector (left and right) at power up (with and without LEDs connected?
What sis the good led voltage on leds connector (left and right)?
Thank you.

[R_J]

Re: Schematic needed for Samsung Power Supply BN44-00502A

The led voltage is marked on the board, it is 191v/367ma. Check RM807, if it is open, icm801 is likely bad, Also check the solder connections on tm801s transformer.

[therealovy77]

Re: Schematic needed for Samsung Power Supply BN44-00502A

Problem solved.
I buyied another power supply module second-hand (from an TV with broken screen) and I solved the problem.
Thanh you.