LG 42PC5D request for knowlege

[scikris]

I was wondering if I could get some advice on a problem I am having with my TV, It's a LG PDP42x40201

Symptoms:

Red light on
>Pushes power button
Green light flashes
Green light sustains
No picture
Has sound

I got the tv like this so I don't know how bright the back light should be when the screen is black, but it doesn't look like the back light is on.

Testing:

power going to z board
v-s: 190.5
v-a: 59.6
5 v: 4.97
(all pretty good by my judgement)

power going to ysus board
v-s: ~3 (decreases longer I leave multimeter lead on it)
v-a: .57
5 v: 4.97
(indicating something is faulty)

My thoughts are that the ysus board is probably messed up and it took out some of the y components on the power supply. So is it just a matter of replacing the power supply board, ysus board and probably the y-drive board to be safe? or are there known issues/components that I can replace to get this thing working? I don't see any bulging caps, but there is an oily residue on the ysus board.

Thanks for any advice, I don't really want to spend nearly 200$ on these new boards when at the beginning of the day I knew nothing about tvs. I don't know if this is even the real problem, I don't see any backlight light up when I push the power button like i would expect…

tl;dr: power supply board bad, don't see bulging caps other easy fixes? Do I have to replace ysus and y-drive boards too?

[PlainBill]

Re: LG 42PC5D request for knowlege

This TV appears to have problems with the hybrids, just like the previous generation did.

My suggestion: Disconnect the power cable to the Y-Sustain and measure the voltages at the power supply. Do the same at the Z-Sustain. Also check fuses on both.

If your preliminary diagnosis is correct, you have a problem. Y-Sustain and Y-Buffer each cost upwards of $70 from reasonably reputable sellers on eBay; the power supply costs over $100.

I doubt it is necessary to replace the Y-buffers, the damage is usually limited to the hybrid. The 15V power supply caps should be checked. Still, the hybrid is $40, and from experience is a pain to remove.

PlainBill

[scikris]

Re: LG 42PC5D request for knowlege

This TV appears to have problems with the hybrids, just like the previous generation did.
PlainBill

Sorry, but what is a hybrid in this context? I'm completely new to TV repair

[PlainBill]

Re: LG 42PC5D request for knowlege

Sorry, but what is a hybrid in this context? I'm completely new to TV repair

See the big black heat sinks in the second and third pictures? The hybrids are under there.

PlainBill

[cadillacman]

Re: LG 42PC5D request for knowlege

check the fuses on the sustain boards....(use a ohmmeter) find a blown one? thats the board with issues. Most likely the hybrid, but i have seen these have smd stuff fail on them as well..

this set does not have a backlight(its a plasma), the light is actually generated within the panel itself.

its ok rookie mistake, untill about 2 months ago i did not know that either...

[b700029]

Re: LG 42PC5D request for knowlege

Sorry for grave digging, but I have same TV and same issue. I feel confident to locate and replace bulged caps, but not much after that.
I wonder if OP ever fixed the issue and what his solution was

[fierce]

Re: LG 42PC5D request for knowlege

I have the same tv with what sounds like the same problem,green light flashes 5 times,but the screen won't turn on. I have a few other LGs are the Hybrids interchangeable? What other problems could I have? No blown fuses by the way.

[tom66]

Re: LG 42PC5D request for knowlege

The hybrids are usually interchangeable if the boards are the same, sometimes if the pin outs match but I wouldn't guarantee it.

[fierce]

Re: LG 42PC5D request for knowlege

The pins are all the same,so is the writing on the back of the board labeling all the pins.

[tom66]

Re: LG 42PC5D request for knowlege

Is it from same or bigger screen size? It should be OK.

[fierce]

Re: LG 42PC5D request for knowlege

It's from the same size screen,almost the exact same looking board

[tom66]

Re: LG 42PC5D request for knowlege

Then it is likely to work.

[fierce]

Re: LG 42PC5D request for knowlege

Ok thanks,now I just gotta get them off the boards

[fierce]

Re: LG 42PC5D request for knowlege

So are the Hybrids the same as far as which sides they're on (looking at the back of the tv),like can I take one from the left side and put it on the right side?

[tom66]

Re: LG 42PC5D request for knowlege

Not as far as I'm aware...