Old Samsung LCD

[n01d3x]

I am trying to repair an old samsung lcd, board
BN44-00264A. I followed the steps I found herehttps://www.badcaps.net/forum/showth...t=26568&page=2
Continuity on all points of the rectifier are ok except for 2&3. All caps look ok visually, I assume its either the rectifier or a mosfet, thoughts. Oh, originally it turned off and wouldn't turn back on, no stand by or nothing. The main fuse was blown and blew a new fuse immediately.

[n01d3x]

Re: Old Samsung LCD

I tried to edit the topic to include the model info, but for some reason it doesn't show up in the title. Here is the info, Samsung LCD LN40B640R3F Power Board BN44-0026A

[budm]

Re: Old Samsung LCD

Can we see the straight shot pictures of YOUR board top side and bottom side?

[n01d3x]

Re: Old Samsung LCD

I'm at work, but I'll take some pics when I get home, thanks!

[n01d3x]

Re: Old Samsung LCD

Best pics I could get, if you need better I can get a better camera later and take better ones. It's the same board as the one in the link I posted. You gave the guy in that post a list a points to test on his rectifier, I did the same and got in the 50 range with the 200 setting on everything except point 2 & 3 I got nothing.

[n01d3x]

Re: Old Samsung LCD

Bump for help. I guess i could just ohm out all of the mosfets and caps, replace any bad ones as well as the rectifier?

[n01d3x]

Re: Old Samsung LCD

One last bump before I give up

[budm]

Re: Old Samsung LCD

OK, your pictures are too blur to use, so I found good pictures at SJ.
Since it blows the main AC fuse, so the shorts will be in the load some where so:
Check the resistance between the two legs of the main filter cap CP815, if it shows <100 Ohms or so, then remove the fuse FM802S to see if the low resistance will go away, if not then you have shorts circuit in the main power supply/ PFC Voltage booster section, if the shorts go away then the shorts are probably in the switching power supply or in the inverter section.

[dick_barton]

Re: Old Samsung LCD

You have include pictures of the inverter boards but you say in your first post that the fuse is blowing on the power supply so surely that's the board you should have initially included with nice clear focused photo's of the top and bottom of the circuit board?

[budm]

Re: Old Samsung LCD

It is power supply/inverter board combo.

[n01d3x]

Re: Old Samsung LCD

Sorry for the blurry pics. Yes this is an inverter\power combo. The resistance on cp815 was around 10, once I removed the fuse it was around 120. Thanks for your help!

[budm]

Re: Old Samsung LCD

Sorry for the blurry pics. Yes this is an inverter\power combo. The resistance on cp815 was around 10, once I removed the fuse it was around 120. Thanks for your help!

10 Ohms with the fuse in place, and 120 Ohms when fuse is removed?
Then you have two bad section, one before the fuse and also after the fuse, I t should not be that low.