Samsung PN50A450 - No Power

[newtothis]

Re: Samsung PN50A450 - No Power

Can you just check on your PSU for a code... starts BN44

Just want to check we have the right service manual

[steveh_131]

Re: Samsung PN50A450 - No Power

I did did check on that and it is the right one. I looked at the pdf posted earlier.

[newtothis]

Re: Samsung PN50A450 - No Power

Ok yes unplug from maniboard side - CN801

Jumper pin 6 and 7 on connector CN807

Jumper pin 9 and 10 on connector CN807

Unplug LVDS cable

Turn tv on

[steveh_131]

Re: Samsung PN50A450 - No Power

Excellent. Should I leave CN807 connected while I jumped them?

[newtothis]

Re: Samsung PN50A450 - No Power

Yes

[tom66]

Re: Samsung PN50A450 - No Power

Pins 3-4 on logic board need to be jumped to get test patterns -- https://www.badcaps.net/forum/showpos...61&postcount=2

[newtothis]

Re: Samsung PN50A450 - No Power

Pins 3-4 on logic board need to be jumped to get test patterns -- https://www.badcaps.net/forum/showpos...61&postcount=2

Oh yeah sorry that too.

https://www.badcaps.net/forum/showpo...61&postcount=2

[steveh_131]

Re: Samsung PN50A450 - No Power

LVDS is unplugged.
Power supply to main board is unplugged at main board.
Jumpered from 3-4 on pins on control board.
Jumpered 6-7 and 9-10 on CN807.

Tried to turn on and didn't do anything.

Noticed that pin 6 is RTN, not GND as Tom mentioned...so I jumped pin 7 to the ground and the tv turned on. It's flashing white red and green and purple, etc. now.

Is this a clue?

[newtothis]

Re: Samsung PN50A450 - No Power

LVDS is unplugged.
Power supply to main board is unplugged at main board.
Jumpered from 3-4 on pins on control board.
Jumpered 6-7 and 9-10 on CN807.

Tried to turn on and didn't do anything.

Noticed that pin 6 is RTN, not GND as Tom mentioned...so I jumped pin 7 to the ground and the tv turned on. It's flashing white red and green and purple, etc. now.

Is this a clue?

Oops sorry about the RTN, error on my part.

Mainboard is at fault then

Main board diagnostics are beyond me at the moment, I would simply replace it.

[steveh_131]

Re: Samsung PN50A450 - No Power

Very cool, thank you!

Maybe this is a dumb question, but if I jumped the PWR_ON like that while it was all plugged in, would that make it work?

Steve

[tom66]

Re: Samsung PN50A450 - No Power

Unfortunately not: the main board is simply not turning on the signal because it is stuck in some kind of fault mode. If you did that you would be left with a slightly glowing black screen with no image. The fact that you got test patterns means the fault is with the main board.

[steveh_131]

Re: Samsung PN50A450 - No Power

Ok, you guys are awesome.

Last question:

I found this on ebay: http://www.ebay.com/itm/Samsung-BN94...50A450P1DXZA-/

I can't find a part number on the main board that matches anything on ebay for this model. It has several stickers with with different part numbers.

How do I tell if this eBay board will match my unit?

[tom66]

Re: Samsung PN50A450 - No Power

See this video:
http://www.youtube.com/watch?v=R1jmj_foId0

[steveh_131]

Re: Samsung PN50A450 - No Power

Thank you, fellas.

I ordered a replacement board on ebay. I will replace it next week when it comes in, and I plan to update this thread with the results for the future use of anyone else with the same problem.

This was very educational and I appreciate all of the input.

Steve

[newtothis]

Re: Samsung PN50A450 - No Power

Your welcome.

Look forward to hearing the results

[steveh_131]

Re: Samsung PN50A450 - No Power

Installed the new main board today.

Fired right up with no problem!

This turned out to be a heck of a good deal. Thank you all for your help. I'm soldering a few new capacitors into a Viewsonic sometime this week, so I'm sure you'll be hearing more from me as I venture into even more unknown territory.

Take care!

[aaronwt6]

Re: Samsung PN50A450 - No Power

Not to dig up an old thread but I wanted to give thanks as always to newtothis and tom66. Got one of these TVs on the bench right now and followed this thread to determine that the control board was faulty. Not sure why more TVs don't have a test mode like this. Sure does make sense.

[johnboy1313]

Re: Samsung PN50A450 - No Power

Aaron, what's the number of the control board? I have a PN50B450 and a C450. If you need the board and I have it, I'll give you a good price.

[aaronwt6]

Re: Samsung PN50A450 - No Power

Thanks for the offer but I already had one on order when I wrote this.