Samsung UN55D6003 BN44-00424A won't power up

[Daveleone]

Hi all! I was given a UN55D6003 TV that won't power up. This uses the BN44-00424A power supply. I've read all the threads on here on both UN55D TVs and BN44-00424A.

My TV has a similar issue where you can hear it cycle (click...click), but backlight does not power up and LCD shows nothing even when shining a flashlight on it. However, mine is slightly different than all of the other posts in that A5V (CNM803, pin 14) is NOT stable. It cycles up and the back to 0, it only gets to ~1.7V (but that could be because my multimeter isn't fast enough to catch it hitting 5V?). It does this even when the main board and LEDs are not connected to the power supply.

A lot of the other threads determined that filed LEDs were the problem. I _can_ rip the TV apart and check all the LEDs, but I'd rather not especially since I'm thinking that this is a power supply problem because of the A5V instability.

Looking for your input.
1) Should I see A5V stable at 5V when the mainboard and LEDs are disconnected from the power supply? (is that the correct expectation, or would it cycle with no load)?
2) From my description, do you think the power supply is defective?

As always, your help is greatly appreciated! Thanks!
--Dave

[R_J]

Re: Samsung UN55D6003 BN44-00424A won't power up

The A5v should be stable, The standby circuit is seperate from the main supplies. shopjimmy has a repair kit for these power supplies, have a look and check the parts it shows to replace, Check the diodes etc. that are mounted to heatsinks.
Usually a ticking sound coming from a power supply indicates a short in the output somewhere, as the supply is trying to start but shuts down, (protection)

[Daveleone]

Re: Samsung UN55D6003 BN44-00424A won't power up

Turns out I had a blown fuse in my multimeter causing bizarre readings. I got a new multimeter and A5V is stable, B5V fluctuates, similar to the other threads. Now I highly suspect the power supply is ok and the LEDs are faulty. Time to take apart the panel!

[Daveleone]

Re: Samsung UN55D6003 BN44-00424A won't power up

Finally got this panel apart. Damn Samsung for using weak metal screws and loctite. I stripped 5 of the screws on the panel frame and had to drill them out. Anyways, definitely a failed LED strip. I counted 24 failed LEDs on the LEFT100 strip (used a voltage generator to test each one). There were ZERO failed LEDs on the RIGHT 100.

Even though the RIGHT100 is ok, I'm planning on buying two brand new replacement strips on AliExpress and replacing both. I figure it's better to have brand new LEDs on both sides. $44 (including shipping) for the pair.

[neilc6]

Re: Samsung UN55D6003 BN44-00424A won't power up

https://www.badcaps.net/forum/showthread.php?t=69627

[Daveleone]

Re: Samsung UN55D6003 BN44-00424A won't power up

Thanks for the link. Yes, my strips have the 8-pin connector. There are other strips with a 2-pin connector. I found the ones I need on AliExpress.

[Daveleone]

Re: Samsung UN55D6003 BN44-00424A won't power up

UPDATE: I received the new LED strips in the mail. Installed them. FIXED!

Here are the strips I used: https://www.aliexpress.com/item/100-...856481262.html