Samsung Power Supply Board BN44-00874F

[Nicktronic]

Thank you all, I will check tomorrow.

[nomoresonys]

If you have not, check DP802 and 803 Diodes on underside of board by the big caps. Also double check all those resistors, make sure none are open or drifted.

[nomoresonys]

I wonder if CP810 is ok.

[lotas]

I posted a pdf in post 20. Your VCC supply is underestimated 10v, but it should be about 18-22v

[Nicktronic]

I will. Is there any chance it could be the FA6B22N?? I was saying that there was 7 volts on the FB line, but am not sure if that is normal or possibly is keeping the IC from fully operating...

[nomoresonys]

There's some very smart folks on youtube, diving deep into how these boards work. In some basic ways they all work the same but of course there's just enough variance in some to make it complicated at times.

[nomoresonys]

Guess this ones too tough for me, maybe test all your blue ceramic caps on top of board, test them in ohm mode in circuit, they should probably read in the m or k ohms. They can be bad and not show externally, I assume you did check all the solder joints paying extra attention to transformers and things on heatsinks, the joints can get micro-cracks that are not easily detected. Just tried this test but didn't work on my meter tho.

[Nicktronic]

Maybe check DM807 and that little transistor next to it.

Did already, they are good.

[Nicktronic]

Let me know if these are sufficient

[nomoresonys]

Make sure none of the resistors are bad or have risen in value, it doesn't take much to mess up the balance.

[nomoresonys]

Can you post a good clear picture of that IC and the mosfet area you replaced? can be two pictures just need a little more detail.

[nomoresonys]

Maybe check DM807 and that little transistor next to it.

[nomoresonys]

Maybe reflow the solder joints on the transformers and anything on a heatsink or any others that may need it, just in case it's a simple thing like that.

[nomoresonys]

That explains it, picture was not very clear.

[Nicktronic]

I am not mistaken in this case, in post #10, the datasheet clearly labels pin 12 as VCC, so it must not have been a match to your IC.

Oh, lol, we are talking about two different ICs....I'm talking about the FA6B22N and you are talking about UCC28064A

[lotas]

UCC28064A and FA6B22N are completely different microcircuits and we were talking specifically about FA6B22N.

[nomoresonys]

What do y'all think? seeming like a capacitor issue maybe?

[nomoresonys]

400-500 Kohms

Ok, this is good, that IC may be alright.

[nomoresonys]

I am not mistaken in this case, in post #10, the datasheet clearly labels pin 12 as VCC, so it must not have been a match to your IC.

[Nicktronic]

Ok, not exactly sure but might be able to get a clue by testing resistance from neg. leg of filter cap to pin 10 VCC, see what you get, done with tv unplugged from power.

400-500 Kohms