Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink

[mp300zx]

Model: PN50C450B1DXZA
Symptoms: Colored thin vertical lines in two places on the right side of screen. One approx. 2 inches wide and the other maybe 1/2" wide. Developed a different issue upon reinserting the cards. Upon power on, screen flashes brightly, then solid black. Red standby LED light flashes red 5 times and stops. Logic board light flashes about 5 seconds on, and two seconds off.


So, I was messing with an old TV that got lines in it a few months back since I have some extra time on my hands. I have read just about every justanswer reply, badcaps article, and off the wall google result page imaginable on this model and its original issue. I've taken all of my voltages and most were within a few volts of spec, and were adjusted to be precise.

Voltages Spec/Actual:
VS: 209/209.6
VA: 55/55
VSC: -178/-178 ****drops to -175 following the flash***
VE: 86/86
2VE: 74/ unable to find test point.

Initially, my only problem was that it had vertical colored lines, so I figured it was the Y buffer board. I was going to replace the Y buffer and Y main at the same time as I read that sometimes the Y main can fault out the Y buffer, generally ruining the replacement.

Physical tests:
Disconnect Y main power supply = Cannot remember... can't reattempt in current state.

Disconnect Y buffer ribbon cable = Left one black horizontal line across screen. Black through sections which colored lines appeared.

Disconnect X main power supply cable = Cannot remember... can't reattempt in current state.

Swap ribbon cables coming from logic board to E and F buffer boards in hope to get the video to swap sides, putting the colored bars on opposite side to test if logic output was bad = No Video

I removed the Y main, Y buffer and Logic Control boards to do some short testing as described in the video by Tom66 on Youtube. I found some shorts to ground in the Y buffer. At this point I came across another good justanswer article and the little box popped up to prompt me to ask my own question. I wanted a photo of my issue to accompany, so I reinstalled the boards. I was careful to seat each ribbon cable and clamp fully, and all connectors. I DID only place a few mounting screws to hold the boards in place... not sure if that could have caused some arcing, ruining some more stuff.

Upon power up, I saw a bright flash, the screen went dark, and the standby LED was flashing red 5 times. I looked at the logic board and instead of the "heartbeat," it had an on/off of 5 sec/2 sec.

This morning, I did some more power tests at each connector and came up with the following short to ground/continuity results:

Y Main
CN5801
Pin 3 - OC1
Pin 9 - YSC

X Main
CN7401
Pin 13 - VDD

CN4001
Pin 14 & 15 - VDD

Main
C123D
Pin 7 - B5V
Pin 8 - B5V
Pin 12 - B5V

CN710
Pin 9 - A3.3V
Pin 10 - GND (Has no Ground)

I was only able to find one fuse on the SMPS/PSU board, and it tests good.

I'm at a complete stop, and have no idea what this could be, or how to fix it. I've followed the Fast Track Troubleshooting manual and tried to jumper the logic board and main>SMPS cable to display the test patterns, but I got nothing.

I'm still new to troubleshooting these, so work with me, please! Thank you in advance!

[mp300zx]

Re: Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink




My vertical colored lines appeared the same as this, just not in the same quantity.

[Alastair E]

Re: Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink

Don't waste your time with this set.

The initial symptom indicated COF Chip or Tab failure in the section of screen with the vertical lines.

These are part of the panel itself, and Un-Fixable.

As to the faults Now present--In Addition to the panel, could be you put summit back in wrong....

[mp300zx]

Re: Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink

Hmm. That's disappointing. I reviewed my photos I took and left everything taped in place.... Its pretty impossible to route cabling anywhere else since they taped so closely to the connectors.

[mp300zx]

Re: Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink

Anyone else? Not to say Alastair's word is not valuable or correct... I'm just curious on the thoughts... Is it really a complete scrap case? :/

[ReeceyBurger123]

Re: Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink

Faulty panel end of IMHO common issue on this model not fixable and will need a whole new screen ! Whats up with Alastair's word he knows alot about PDD's ?

[mp300zx]

Re: Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink

I was saying that I was just asking for more input on the symptoms and possible issues. It seemed that the vertical cool bars could be fixed with the Ysus board and y main board being fixed.

Just looking for information. Not really just a "scrap it" type deal. I'm trying to learn as much as I can.

And as far as Alastair's word, I was saying that it's not a matter of it not being good enough or incorrect or that he knows nothing. I'm just looking for more. I'm sure he is very intelligent given his status on the forums.

[Alastair E]

Re: Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink

Nothing wrong with a second-opinion...

That Alastair E, He dont kno' Nuffin' Haha, Status--? 'E be a glorified bin-man!............

[mp300zx]

Re: Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink

Looks like I'm not going to get any other information out of the community =/

I was hoping for some insight and not just a "throw it out" answer, unless it really is worth nothing. The boards are cheap, so I hate to throw it out if something board-wise can be replaced and clear up the issue.

[awyatt2]

Re: Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink

there is no board that you can replace to fix it the screen, it has bad cof on the film going to the tab bonds or tab bonds themselves. either look for a replacement screen or part it out.

[Alastair E]

Re: Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink

Looks like I'm not going to get any other information out of the community =/

I was hoping for some insight and not just a "throw it out" answer, unless it really is worth nothing. The boards are cheap, so I hate to throw it out if something board-wise can be replaced and clear up the issue.

Nothing is Impossible--seeing someone Made it in the first place, it is not inconceivable its possible for it to be repaired.

However--With the equipment at our disposal--ie, any TV repair place anywhere on earth probably--Its impossible.

It would need to go back to the factory that Made the panel, have them remove the COF thats suspect/faulty and replace it with new using their 10 million dollar bonding-machine....
--That is, IF the old one can be removed and leave the panel traces intact, Ive no idea....

--On a panel with several thousand hours on it already--Its highly likely its days are numbered anyway,--so what would be the point--Even if (Somehow) you got the factory--probably in another country, probably Korea or China..., to do this work--And at what cost the repair!!

--Just shipping a PDP across country is expensive--let alone across the world!

They would be much happier to sell/supply a complete new replacement PDP that is guaranteed to be good for several thousand hours, whether the rest of the set would be is certainly debatable...

So--As they say, Nothing is impossible, just completely impractical.

[mp300zx]

Re: Samsung PN50C450B1DXZA Screen flash, red LED blink, Logic Slow Blink

Thanks Awyatt! You basically said what Alastair said, but the part about the boards having nothing to do with it was a little more e guidance. I was still under the impression something was causing it at the board.

Alastair.... Damnit man. That's an in depth reply. And I know you know your shit. I wish you had just said that earlier! Haha.
So, vertical red lines in a plasma are not fixable with a replacement board and are due to a bad COF. That's_______ on film... Right?

That's a shame. Any clue what happened or what's causing the bright flash at power on?

Sorry for bugging. I'm just trying to learn what I can by speaking directly. Sometimes searching can be mind boggling as you get conflicting response.