Samsung 32 Inch power supply problem BN44-0260A

[provider10]

Hi
This set uses the BN44-0260A Power supply
It came in with IC UM8015 (ICE3BR0665) Blown
Replaced IC but now I have a stable 13 Volt but the 5volt rail is pulsing around 2.5 volts. Checked diodes and caps but getting nowhere
Can anybody Help

James

[provider10]

Re: Samsung 32 Inch power supply problem

Hi looking through the forum I find that the post from Moolink on 07-28-2012, 03:43 AM is basically the same set. But the diodes in my set seem to be OK. The fault occurs with or without the main board connected

Thanks

[dick_barton]

Re: Samsung 32 Inch power supply problem

What voltage do you have on inductor LM851
If it is pulsing then I would lift one end of LM851 and check the voltage across CM852 and if it is not pulsing then I would check QM853 However if it is still pulsing then I would check DM851.

I can't find a schematic but I did find this
https://archive.org/details/Samsung_...0260A/mode/2up

[R_J]

Re: Samsung 32 Inch power supply problem

Check the voltage across CM804 and see if it is steady (around 20~25vdc) CM804 or CM808 could be bad. You should also check the voltage across the main cap CP815, this voltage should be around 385vdc if the pfc circuit is working.

[provider10]

Re: Samsung 32 Inch power supply problem

Hi Guys

Thanks for the help. I found the voltage across CM804 was only 12v. Changed the caps didn't help . Found Zener diode ZM801 faulty

Thanks for the assistance

James