Samsung PLASMA PS50C450B1W: Y-Buffer board Problem!!

[Ahakim]

No light on screen. TV ON by TLC or by hand on front panel: power red led blinks once and TV goes back off. Relay can be heard switching on and off again repeatedly...
When Y-main board or Y-drive Buffer completely disconnected: relay doesn't switch back off and green led on MAIN board remains lit.
Most probably (my diagnostic says) there is a short on Y-Buffer...Am I right? Where Should I look for this short? There are 8 ICs of 33*4 pins each on the board! Are theese "microscopic" ICs replaceable? or should I look for a board for replacement? HHHelp!!

[Alastair E]

Re: Samsung PLASMA PS50C450B1W: Y-Buffer board Problem!!

Unplug the buffer-board from the Y-Main, (can leave it connected to panel by the flex-connectors), plug all cables back into Y-Main and re-test.

If it still trips, then the fault is unlikely the buffer-boards, but likely on either the Y-Main or the X-Main as the supplies loop from Y to X on these sets.....

[Alastair E]

Re: Samsung PLASMA PS50C450B1W: Y-Buffer board Problem!!

Also--If it trips, disconnect the X-Main thick cables and then re-test.

If it still trips, then its likely the Y-Main is the culprit, and probably has a short on the Vs supply-line....

[Ahakim]

Re: Samsung PLASMA PS50C450B1W: Y-Buffer board Problem!!

Sorry...I don't really get what you said in the first reply. Can you be more explicit. Ok ...I'll try ... Thanks anyway.
Note: There is only ONE long Y-Buffer board in this TV.

[Alastair E]

Re: Samsung PLASMA PS50C450B1W: Y-Buffer board Problem!!

Ah--yes, should have thought, Have a couple of 50" buffers here, as you say--one long board--bit like the 42" version I have running here.....

The Buffer is plugged into the Y-Main--yes? (Or is it the type--that has the Buffer--as part of the Y-Main,--all one board?)

Unplug that buffer from the Y-Main, then re-test as above....

A couple of pics would help clarify the chassis, the boards, the connections etc....

[Taban]

Re: Samsung PLASMA PS50C450B1W: Y-Buffer board Problem!!

hello, I had the same fail. At first time the tv was died. only can hear clikc the coil or psu. First I Replace the x-main LJ41-08457A, and the I have sound but no picture. After that I replace the y-main LJ41-08458A and the buffer board LJ-4108459A and the tv continues only with sound. when i begin to repair this tv a found a shortcircuit in the mosfet of the x-main. I bought these boards on flattvparts.com and they are used. I´m not sure that the boards are good. the last change its replace the psu, because the Va and Vs start good, but going down too fast when start power. if I disconnect the x-main board and the y-main board these voltages dont be ok.
i bought the psu, used too, and i will try for the last chance.
sorry for my english, I am from Spain.
If somebody knows some solution I will be gratefull.

thanks
javier

[Alastair E]

Re: Samsung PLASMA PS50C450B1W: Y-Buffer board Problem!!

Sounds like you have bought some faulty boards and your original board/s have fault/s too...

IS there ANY combination of boards from original and replacements that allow the set to 'run'--but have no picture-- as in--sound only, and the Vs etc stay supplied?

How is your electronic knowledge...? Can you trace short circuits, test semiconductors, replace individual components etc...?

If not, I would send those boards back to the supplier as (probably one or more) faulty, and get known working and TESTED boards from a different vendor.

I have a full set of boards from a 50C450 set, BUT have NO IDEA if they are good or not, (therefore, I cannot sell them) they came from a broken screen set and I haven't a 50" set to test them in, Ive been waiting for a 50" to try them in to see.....

Have you tested the Vsc voltage on the Y-Main? Ive had a situation with the 42C450--where this voltage didn't come up Fast enough (because I put a larger value cap in the stage) and the set wouldn't start on first attempt, Va and Vs were shut down by control board--Switch off, then straight away back on, would run normally all day till next day.

Think maybe your Vsc isnt there, too low or something wrong with that inverter stage on the Y-Main--that is if there's no blown/broken parts obvious on the Y-Main.....

[Taban]

Re: Samsung PLASMA PS50C450B1W: Y-Buffer board Problem!!

I'm technician in electronics. I was working for 4 years in telecomunication electronic repair. Now I am working in industry electronics.
Flatvparts.com say that they test all the boards, but I'm not sure. I'm not sure that the panel plasma its ok. But I will try replace all the boards. The last chance its replace the psu.
The original fail was clicking the start relay. And the normal solution its replace the xboard. But I replace all the boards and I only get the sound. But the picture its dark. I will tell what happen when replace the psu.
Thanks