LG 50PA5500 Plasma - No picture then no sound

[freakaftr8]

Re: LG 50PA5500 Plasma - No picture then no sound

I have this TV here at my shop I'll look and see what the red light means give me a minute

[Moreno83]

Re: LG 50PA5500 Plasma - No picture then no sound

Dont worry , i was also new ( still are ) and thanks to these guys i learned alot!

I think the tv is in standby mode and when you try to turn it on it detects a problem and it shuts off
Its the same problem why it shut off in the first place.

[Mac 108]

Re: LG 50PA5500 Plasma - No picture then no sound

Thanks for being patient with me. Obviously, I'm clueless when it comes to this sort of problem.

If the red light in front left hand corner of the TV is on, does that mean the TV is on? At first I thought it did. This TV has never worked since it was given to me, so I don't know for sure and I don't want to give the wrong information.

[tom66]

Re: LG 50PA5500 Plasma - No picture then no sound

Not necessarily... I've had an LCD like that. Standard story, "customer says" TV lost picture then a day later lost sound. Picture was inverter fault... sound was them muting it accidentally when the picture was out.

[freakaftr8]

Re: LG 50PA5500 Plasma - No picture then no sound

Don't know yet. The power supply may not be getting the turn on signal from the main board. That's why we have to go thru a series of tests to determine what's going on.

[Moreno83]

Re: LG 50PA5500 Plasma - No picture then no sound

Isnt this just a PS problem? I mean , first the screen goes black and later on the sound is gone. Is it not the PS losing its voltage to the other boards? Just trying to think with you guys...

[tom66]

Re: LG 50PA5500 Plasma - No picture then no sound

You shouldn't test fuses with power on, always unplug and wait for set to discharge.

I meant voltage tests are to be made with power on.

[Mac 108]

Re: LG 50PA5500 Plasma - No picture then no sound

With the TV on, the fuse shows 008. Does that mean this is my problem?

[tom66]

Re: LG 50PA5500 Plasma - No picture then no sound

Ok, now try with the Z-sustain out... by the way, are you turning the TV on (taking it out of standby)?

[Mac 108]

Re: LG 50PA5500 Plasma - No picture then no sound

Fuse tests good

[freakaftr8]

Re: LG 50PA5500 Plasma - No picture then no sound

Check the fuse above the two yellow transformers on the power supply with an ohm meter. If it's open that's your problem

[Mac 108]

Re: LG 50PA5500 Plasma - No picture then no sound

With the Y-sustain board disconnected and the TV off, Vs 002 Va 008.

[tom66]

Re: LG 50PA5500 Plasma - No picture then no sound

Ok, now remove the connection between the power board and Y-sustain board; the Y-sustain is the large left hand board.

[Mac 108]

Re: LG 50PA5500 Plasma - No picture then no sound

With the TV off, Vs reads 014 and Va reads 008. When the TV is on, it reads nothing. I had it set to 1000v.

[tom66]

Re: LG 50PA5500 Plasma - No picture then no sound

OK, using it, test the Vs and Va voltages on the power supply. These are usually available on test points. The multimeter needs to be set to the highest DC range available (usually 600 or 1000V.) For convenience, you can attach the black probe to the chassis. For now, leave the top buffer board out of the set.

[Mac 108]

Re: LG 50PA5500 Plasma - No picture then no sound

I do. I have a Velleman DVM890F. http://www.vellemanusa.com/products/...=enu&id=521426

[tom66]

Re: LG 50PA5500 Plasma - No picture then no sound

Good. That is what was needed, thanks for that.

Do you have a digital multimeter available?

[Mac 108]

Re: LG 50PA5500 Plasma - No picture then no sound

Here's the board I removed:

[Mac 108]

Re: LG 50PA5500 Plasma - No picture then no sound

I'm not sure which those are. TV is at work. I'll post pics in the morning of exactly what I did.

Thanks for the help so far.

[tom66]

Re: LG 50PA5500 Plasma - No picture then no sound

Just to make sure, you unplugged the Y-buffer from the Y-sustain board?