Samsung BN44-00506A power board dead no standby

[london-freddie]

Hi again all
just been given for free a dead Samsung LT27B3000EW LED Tv, it was going to the skip
Just wasted several hours of my life looking at the power board, but it is beyond me
Power board is BN44-00506A
No output voltages at all on any pins, no standby voltage or led
I do have 338V at the big cap
Anyone had any dealings with this board or any ideas where to start looking next
Nothing appears visibly popped on this board
thanks in advance

[petehall347]

Re: Samsung BN44-00506A power board dead no standby

check fuses and fets

[london-freddie]

Re: Samsung BN44-00506A power board dead no standby

pics of boards

[dick_barton]

Re: Samsung BN44-00506A power board dead no standby

Post #11 may interest you.
https://www.badcaps.net/forum/showthread.php?t=54437

[dick_barton]

Re: Samsung BN44-00506A power board dead no standby

Is there a burn mark on this resistor or just a speck of dirt?

[london-freddie]

Re: Samsung BN44-00506A power board dead no standby

thanks for that, re the resistor no burn mark, however looking even closer at this board I think it has had some work done on it in an attempt to fix it.
some solder joints been done looks like the little blue cap CM804 next to that resistor has been changed out, also looks like CM801S has also been played with, me now thinking may be easier just to try and source another board

[london-freddie]

Re: Samsung BN44-00506A power board dead no standby

just been looking at that post you pointed me towards, looks exact same problem as my board even down to same components, coincidence ???

[ReeceyBurger123]

Re: Samsung BN44-00506A power board dead no standby

Checked the output diodes for SC ?

[dick_barton]

Re: Samsung BN44-00506A power board dead no standby

just been looking at that post you pointed me towards, looks exact same problem as my board even down to same components, coincidence ???

No, it's probably a standard failure for this board.

[london-freddie]

Re: Samsung BN44-00506A power board dead no standby

Thanks for the help guys
Pretty sure this board has the same problem as Modrobert in the previous link
looks like STR-W6052S is shorted
CM804 blue ceramic looks to have been changed markings on cap are 47k 2kw not sure if this is the correct cap for the board
Diode DM801 is short when fitted, also checked this off board still short
Anyone know the correct blue ceramic that should be fitted

[london-freddie]

Re: Samsung BN44-00506A power board dead no standby

Output diodes all seem to be ok

[dick_barton]

Re: Samsung BN44-00506A power board dead no standby

In the link I gave earlier

I have replaced IC STR-W6052S, ceramic cap [CM804] (0.22nF 1000V "221K 1KV") and the TV is working again.

[london-freddie]

Re: Samsung BN44-00506A power board dead no standby

ok will get these parts ordered and give it a go, thanks

[london-freddie]

Re: Samsung BN44-00506A power board dead no standby

ok have ordered this ic STR-W6052 and diode DM801 which was def short, I have the cap CM804 221 1Kv
However with these components now removed from the board I now have another question re do I have another problem on this board
I believe the ic has one leg which is ground, however when checking the board connections with the ic removed I am getting a ground on all 3 solder points on one side of where the ic solders in, dont know what pin numbers they are but they are all on the outside edge of the chip/board,
Does that sound right or am I worrying over a problem that is not there, I am thinking there is something else on this board that has a short to ground

[london-freddie]

Re: Samsung BN44-00506A power board dead no standby

update !!!! got a used power board off ebay tv is now working again, now wait for ic and diode to arrive and try and get old faulty board working
thanks for the help guys

[dick_barton]

Re: Samsung BN44-00506A power board dead no standby

Were you able to compare the two boards regarding your concern over the 3 pins grounded.

[london-freddie]

Re: Samsung BN44-00506A power board dead no standby

No, did not check just put the board straight in the tv and powered it up, may take it back out and check out of curiosity though, I was being a bit impatient as the ic is coming from china and did not want to wait when I saw this board on ebay got it next day

[andrearimini]

Re: Samsung BN44-00506A power board dead no standby

Hi all, i'm trying to repair this board and lost few hours without no results.
I've changed STR-W6052S (the old one makes a "click loop" when powered) and CM804, checked all diodes and capacitors, changed everything was faulty but this damn board doesn't work and nothing appears on output.
It seems STR-W6052S (correctly powered) doesn't oscillate and obviously transformer doesn't work.
Does anyone has any suggestion? Any schematics? My curiosity is higher than time i've spent on it so i'd like to find the faulty.
Many thanks, have a nice day.

[gray.matter]

Re: Samsung BN44-00506A power board dead no standby

Hello new member here looking for helpwith
Samsung BN44-00506A power board dead no standby, but i can hear something cycling on the board and advice on wat to check or replace?

Many thanks

[vinceroger69]

Re: Samsung BN44-00506A power board dead no standby

Hello new member here looking for helpwith
Samsung BN44-00506A power board dead no standby, but i can hear something cycling on the board and advice on wat to check or replace?

Many thanks

Can you upload good clear pictures of your power supply front and back if possible.