Samsung 26in LN26B360C5D no picture good sound

[DakotaH]

I have a Samsung tv BN44-00259A power/inverter board. The tv powers on and indicates that the buttons work just fine. I have taken apart to the screen to get in behind where it is lighted to run my own light and it shows the image but the light doesn't light up. I have full power to the video board in it and everything else works just not the back-light. I wasnt sure if it was the inverter board or the lights. on the inverter board the heat sinks hs4 and hs1 isn't producing any heat unlike the rest the one has 2 transistors on it and the other i am not sure cause i am not to savvy on electronics but i know some and how to test point to point.

[ratdude747]

Re: Samsung 26in LN26B360C5D no picture good sound

Moved out of the FAQ. Please do not post questions there... it is only for formal or semi-formal how-to guides.

[budm]

Re: Samsung 26in LN26B360C5D no picture good sound

Please post good, clear, focused pictures of all the board so we can see how they are connected together, then the pictures of this power supply board. Use 'GO ADVANCED' to upload the pictures.

[DakotaH]

Re: Samsung 26in LN26B360C5D no picture good sound

5v power at inverter

[budm]

Re: Samsung 26in LN26B360C5D no picture good sound

OK,disconnect the multi white cable from the power supply-inverter board combo that goes to the main board, if the power supply-inverter board is OK, the backlights should come on when you plug the TV into the outlet. We need to find out the reason the backlights are not is due to main board not sending the BL_ON to the power supply-inverter board or the power supply-inverter board is bad.
By the way, what is the P/N of this power supply board, the pictures are way too out off focus for me to read any labels or names on the board. Can you please take better pictures? It should be BNXXXXXX for the P/N
Service manual:
http://elektrotanya.com/samsung_ln26.../download.html

[DakotaH]

Re: Samsung 26in LN26B360C5D no picture good sound

with that cable unplugged it still doesn't turn on the backlight

[budm]

Re: Samsung 26in LN26B360C5D no picture good sound

OK, then we need to troubleshoot the power supply-inverter board, so as I have indicated, I will need good clear pictures of both sides of this power supply board, they must be clear enough for me to read the labels and traces, just remember I do not have the board in front of me to look at, so good pictures are very important.

[DakotaH]

Re: Samsung 26in LN26B360C5D no picture good sound

Bn44-00259a

[budm]

Re: Samsung 26in LN26B360C5D no picture good sound

OK, you can download the diagram for this board here:
http://www.tgohome.com/ServiceManual...g_BN44-00259A_[SCH].pdf

Time for bed for me, I will look at the diagram tomorrow to see where to test the voltages.

[DakotaH]

Re: Samsung 26in LN26B360C5D no picture good sound

here is the best i can take with the camera at hand

[DakotaH]

Re: Samsung 26in LN26B360C5D no picture good sound

here is the last few

[DakotaH]

Re: Samsung 26in LN26B360C5D no picture good sound

hey i had to get it from a different link cause it wasnt working with your link

[budm]

Re: Samsung 26in LN26B360C5D no picture good sound

OK, we can work on the power supply-board by itself without having the cables from the main board attached. Please check the DC voltage on the fuse FM802S, it should have about 390~400VDC between the fuse and the negative leg (this is the primary circuit ground ref point) of the main filter cap CP815.
Be real careful since you will be working in the LINE/HOT side of the circuits, do not touch anything with your hands, you should plug this TV into a GFI outlet to protect yourself.

[DakotaH]

Re: Samsung 26in LN26B360C5D no picture good sound

and its dc voltage? i went to school for electronics and i normally work with high voltage stuff so i know the risk

[budm]

Re: Samsung 26in LN26B360C5D no picture good sound

Yes, DC voltage.

[DakotaH]

Re: Samsung 26in LN26B360C5D no picture good sound

im only getting 56

[DakotaH]

Re: Samsung 26in LN26B360C5D no picture good sound

cap is at 165

[budm]

Re: Samsung 26in LN26B360C5D no picture good sound

Fuse check OK then?

[DakotaH]

Re: Samsung 26in LN26B360C5D no picture good sound

fuse ohms at 2.7

[DakotaH]

Re: Samsung 26in LN26B360C5D no picture good sound

QP802S gets really hot and thats the only one heat sink that gets hot