Samsung PN60E550D1FXZA Won't power on

[MagicSmoke]

After a power surge resulting in tv not powering back on after surge.

Trying to work on the power supply. When its plugged in I have 4.2v on ps-on and 5.2 on stby. But I get no standby light on unit. Using power switch results in nothing happening. No clicks or buzzing from PS. This is with cable to X-main disconnected and main board still plugged in. No led lit on logic board either.

Removed PS for testing, jumpered ps-on with ground and get correct voltages on main board connector. Which is 15v and 5.3v. But no clicks like my other plasma smps does when turned on.

On X-main connector 15v and 5.3v are correct but get no VA or VS volts at all. No spike to 0 when jumper first inserted to ps-on. I replaced all caps except for the 2 large 450v, 1 250v and a 100v 470uf. None showed any visual bulging or damage.

My camera is not that great so pics are not up to par. Model # on ps is BN44-00512a or PSPF391501a.

Nothing on either side of board is burnt or exploded, some discoloration around the 2 green disc resistors close to AC in. Anyone have any idea what to look at next?? Thanks. Todd

[tom66]

Re: Samsung PN60E550D1FXZA Won't power on

Sounds like main board fault.
Can you supply a picture of the control board?

[MagicSmoke]

Re: Samsung PN60E550D1FXZA Won't power on

Will get it out and get pics up in just a minute or 2

[MagicSmoke]

Re: Samsung PN60E550D1FXZA Won't power on

Got main out but nothing looks burnt or degraded. No traces fried from surge. Cant tell about chip under the heat sink though.

No components on back side of main just the circuit traces. None look damaged under the magnifying lens.

Could the power surge wipe the programming on the eeprom chip?

[tom66]

Re: Samsung PN60E550D1FXZA Won't power on

Damage is very rarely seen.
The control board is to the left of the main board. Don't remove it from the set. For this test, all boards should be installed as before.

[MagicSmoke]

Re: Samsung PN60E550D1FXZA Won't power on

Not seeing the control board. My set looks like the one here


Will reinstall all boards and await next instructions. Thanks.

[tom66]

Re: Samsung PN60E550D1FXZA Won't power on

That's interesting - the control board is built into the bottom panel driver, hope it can be replaced if bad. You may have to remove the bottom plastic stand base to see it. You are looking for the "LOGIC/Buffer Board"

[MagicSmoke]

Re: Samsung PN60E550D1FXZA Won't power on

Okay I know which one that is, will take base off. Do I need to remove the Logic/buffer board?

[tom66]

Re: Samsung PN60E550D1FXZA Won't power on

Keep it in the set for now.

[MagicSmoke]

Re: Samsung PN60E550D1FXZA Won't power on

Base off, board has 2 fuses smd, both test good. No visible damage to be seen while installed. One ribbon cable appeared to be off just a bit so I reseated it in the connector.

Logic board looks like this one. Sorry for the link but camera won't take a good pic indoors.

http://www.shopjimmy.com/media/catal...22111A-TOP.jpg

[tom66]

Re: Samsung PN60E550D1FXZA Won't power on

OK, right hand side of the board, near the top, you have four holes marked 1,2,3,4. Block marked CN2008. You need to jumper holes 3 and 4 together. A piece of wire, alligator clip, etc. works fine.

Then disconnect the connector between the power board and main board on the main board side, and connect the PS ON pin to GND with a piece of wire.

When you plug the set in you may or may not see test patterns, so let us know.

[MagicSmoke]

Re: Samsung PN60E550D1FXZA Won't power on

Jumpered 3 & 4, Jumpered ps-on to ground. Nothing no led, no glow, no patterns, no sounds of any kind. Cant see any damage to any components???

All other cables connected except ps to main board as instructed.

[tom66]

Re: Samsung PN60E550D1FXZA Won't power on

OK, on PSU, can you test for Vs and Va voltages?

[MagicSmoke]

Re: Samsung PN60E550D1FXZA Won't power on

Yes ps has test pads for VA & VS but I did not get any voltage ever out of ps when I tested it out of chassis except for the 4.2v,5.3v and 15v. Not even a spike on VS or VA when first powered on. See 1st post. Will retest with everything installed and ps jumpered like in post 11. Be back in a few with results. Thanks.

[tom66]

Re: Samsung PN60E550D1FXZA Won't power on

Yes, you will need VS ON signal from ctrl board to get Vs & Va, to prevent damage to PDP & sustains from incorrect sequencing.

[MagicSmoke]

Re: Samsung PN60E550D1FXZA Won't power on

Retested with everything connected except ps to main. Is this correct? If not will reconnect and try again.

With ps to main disconnected and jumpered I got 8v on VA and 0v on VS.

Just to be sure I reconnected ps to main w/jumper still installed and got the same readings. 0v VS and 8v VA.

Panel sticker says VS should be 211v VA 57v.

[MagicSmoke]

Re: Samsung PN60E550D1FXZA Won't power on

Does this indicate a bad PSU or other board failure? Thanks.

[tom66]

Re: Samsung PN60E550D1FXZA Won't power on

OK, now try Vs/Va but unplug the X- and Y-main boards.

[MagicSmoke]

Re: Samsung PN60E550D1FXZA Won't power on

With all cables disconnected at X & y main boards, all others still connected I get 0v on VA & VS on test points on PSU.

Cables I disconnected were CN5000 & CN5001 on Y drive

CN4003, CN4004, And CN4005 on X Main according to schematic here

[tom66]

Re: Samsung PN60E550D1FXZA Won't power on

It does seem to be pointing towards a bad PSU. Just to make sure could you measure the voltage at VS ON on the control board or power board, it should measure >2V