Samsung LN32C540F2D will not power up

[mrb3715]

Hi everyone,
I have a Samsung LN32C540F2D, Ver CN05, that will not power up. I was watching it a few days ago and it shut off like i hit the power button. The red standby light is illuminated. I visually inspected the power supply board, and main board, and found nothing interesting. All of the caps looked good, no bulging, leakage, etc. I checked the P_ON line for the 5V feedback from the main board and it was at 0 volts. I kept my meter on that pin at the power supply and touched the power button on the face of the TV. The P_ON input to the power supply board jumped to 1.35 volts for a couple of seconds then went right back down to 0 volts. This happens every time i hit the power button. The main board is part number BN96-16368A V2004.1. The power supply board is part number BN44-00338B and the date on it is in 2010 if that matters. Thanks for any help!!

[budm]

Re: Samsung LN32C540F2D will not power up

Try disconnecting the LVDS cable between the main board and the T-CON board to see if it will power on OK.
Also post good clear pictures of the back of the TV and the boards so we can see what we are dealing with.

[mrb3715]

Re: Samsung LN32C540F2D will not power up

I believe I disconnected the cable you suggested and still no change. To be sure i disconnected the correct cable I have attached a picture of it as well. Here are pictures of the main and PS boards. Thanks!

[mrb3715]

Re: Samsung LN32C540F2D will not power up

After doing a little more research I think that the T-CON is part of the main board in this model. The only other board on the back of the TV other than the ones in the pictures is the high voltage board.

[martino]

Re: Samsung LN32C540F2D will not power up

you need to read this thread >>>>>>>>>>>

https://www.badcaps.net/forum/showthread.php?t=30259

[mrb3715]

Re: Samsung LN32C540F2D will not power up

WOW! That sounds pretty familiar. I will try jumpering the 5V stby pin to the P_ON pin and see what voltage I have being output by the PS. If the power supply works as it should with the 5V applied to the P_ON pin, is it then logical to say that the main board is faulty since it is not providing the 5V to P_ON itself? Thanks!

[budm]

Re: Samsung LN32C540F2D will not power up

Ah, I forgot about that thread. Make sure not to have the cable connected between the main board and the power supply board, otherwise the PS_ON will be kept low by the main board.

[martino]

Re: Samsung LN32C540F2D will not power up

I remember it cause I have the same tv with the same problem. You will find when you power up the psu with the jumper, that the voltages will act like in that thread. Very common on those boards.
Parts can be bought on eBay. Just eBay search your board number

[martino]

Re: Samsung LN32C540F2D will not power up

http://www.ebay.ca/itm/SAMSUNG-LN32C...item2c73b563cf

There ya go

[budm]

Re: Samsung LN32C540F2D will not power up

By the way, this is the SCH of the BN44-00338B (provided by TOM66) so you can see the suspected IC and the cap, but we will wait until you do the force on first.

[mrb3715]

Re: Samsung LN32C540F2D will not power up

I will try this as soon as I get home and report back, thanks for the help!

[mrb3715]

Re: Samsung LN32C540F2D will not power up

Well it took me a little while, but after taking the readings at the power supply they seemed odd like in the string you posted for me earlier. I purchased the chip and capacitor and replaced them today but it didnt work, still standby light on, but no power on, any more ideas? Now however I have no output from the power supply board at all. I triple checked my solder joints and all, everything looks great. wondering if i got a DOA chip?? Thanks!

[martino]

Re: Samsung LN32C540F2D will not power up

Did you try a force on after replacing the parts?
Is there by chance a insulator between the chip and the cooling block that didnt get installed?

[mrb3715]

Re: Samsung LN32C540F2D will not power up

I did do the force on, but still no outputs other than the 5v for the stby light. there was no insulator between the chip and the heatsink. there was a bit of thermal compound so i put some on the new chip but that was it. I looked over my work several times but am at a loss. Budm, for some reson i am not able to open the schematic you posted, is it possible to email it to me?

[martino]

Re: Samsung LN32C540F2D will not power up

Only 5volt standby, no other voltage at all?
Wonder if there's something a miss with how you do the force on.
Could you explain how you do that? Or a pic would be even better.

[budm]

Re: Samsung LN32C540F2D will not power up

You can directly download the SCH here:
http://www.tgohome.com/ServiceManuals/

[mrb3715]

Re: Samsung LN32C540F2D will not power up

Thank you for the link! Martino, i had 5V on pin 16 of the power supply output connector and I jumpered it to pin 18 which was indicated to be the PS_ON pin. I have a bit of new info. The leftmost pin of the IC801 that I replaced is fluctuating between 140V and 280V. The rightmost two pins fluctuate between -3V and approx 15V. The fluctuations are simultaneous from input and output. Sorry I am not a TV repair guy normally, just trying to help out my mom. I will definitely tale a picture of what i am doing tonight when i get back home if that will help. I have downloaded the PS board schematic so that will help. Thanks for all of your help!