Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

[Michale32086]

Got in a Sammy PN63...

Initially, voltages were all over the place at power up.. Determined it was the Y-SUS.. Replaced it with a probable good one...

Now I get Sammy Startup Tones and voltages are good. But nothing on the display panel and voltages drop like a rock after initially reading GOOD...

No obvious bad caps and fuses all check out..

I was thinking Power board, but don't think I would get good voltages initially if the Power PCB was toast...

Control board??

[Michale32086]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

Speaking of the Control Board..

It has an LED that has a pattern when the TV is turned on.. 6 sec on, 3 sec off, 6 sec on, 3 sec off, etc etc etc...

There are also a pair of jumpers that, if I remember right, can be used for diagnostics??

[R_J]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

Your plug CN2006 on the control board is NOT seated properly. The leds indicate temperature and indicate the board is working

[Michale32086]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

Your plug CN2006 on the control board is NOT seated properly. The leds indicate temperature and indicate the board is working

DOH!!! Thanx...

[Michale32086]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

Fixed it.. Didn't change anything..

One thing I noticed.. Normally, when you power up the TV, the Power LED blinks a couple times and then goes off and the TV comes on..

IN this case, the Power LED stays on...

[mmartell]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

You mean doing as R_J suggested fixed it or something beyond that ?

[Michale32086]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

You mean doing as R_J suggested fixed it or something beyond that ?

I fixed the issue that RJ pointed out.

Unfortunately, it didn't fix the problem in the TV..

Due to the Power LED not functioning normally (stays on after TV powers up) I am leaning towards the Main Video Board...

[Michale32086]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

I have an opportunity to buy all the parts for this TV sans the Power PCB for $100....

I think I am going to go for it cuz it doesn't look like a Power issue...

[Alastair E]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

Buffers or Xsus....

[freakaftr8]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

Freeze that IC under the wafer to the right of the yellow transformer on the ysus. Then immediately power up. See if you get picture. I believe this is an infinion IC tjat controls VSCAN

[Michale32086]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

Freeze that IC under the wafer to the right of the yellow transformer on the ysus. Then immediately power up. See if you get picture. I believe this is an infinion IC tjat controls VSCAN

I'll check that, once I get the LG off the bench... Thanx...

[Michale32086]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

Freeze that IC under the wafer to the right of the yellow transformer on the ysus. Then immediately power up. See if you get picture. I believe this is an infinion IC tjat controls VSCAN

No luck..

I froze the marked component and still got the same.. Sammy tones, no display...

The replacement parts should be here Thu... As long as the problem is not a bad Power PCB, I should have this up and running by Thu.

Thanx for the reply...

[Michale32086]

Re: Samsung Plasma PN63C550 Replaced Y-SUS Voltages Good, Then Drop

OK Looks like the problem was the Y-SUS board...

I got the gamut of parts from this model.. All but the Power PCB...

Replaced the Main.. Nope.. Still no go.. Replaced the Control Board and then X-SUS.. Nope...

Replaced the Y-SUS... Ahhhhh Houston, we have a picture!!

So, then I reversed my steps and put all the old boards back in... X-SUS, Control Main... All good..

Thanx for all the replies.. Chalk this up as another win...