LG 50PC3D Power Issues.

[ZRICE28]

Hello everyone. I'm new here and came across a few other posts from members who seem to have been experiencing similar problems to what I am. They all seemed open ended, and I haven't found a solution yet. I'm to tv repair, but learn quickly. I have had luck in the past with simple capacitor replacement on a few other tvs. This one seems to be a bit trickier.
I picked up a lg 50pc3d. It flashed three times and powered off. I bought a cap kit and replaced 9 10v 3300 uf, and 3 others, whose values I don't have in front of me right now. Same problem, turns on, and shuts back off, now the optical light on the back comes on though. I unplugged both of the other boards from the power supply, same result. I'm lost now. Thank you in advance.

[ZRICE28]

Re: LG 50PC3D Power Issues.

I found some of tom66's posts regarding ac detect. Just checked that, and the voltage was 4.85 and only dropped to 4.83 when it clicked itself off. Same thing with the ysus board unplugged.

[tom66]

Re: LG 50PC3D Power Issues.

And with Z-sus unplugged?

[ZRICE28]

Re: LG 50PC3D Power Issues.

Doesn't z come from y? 5v off of the power supply going to ysus is only 1.3. V-a is1.0 and drops. V-s is.068 and drops.

[tom66]

Re: LG 50PC3D Power Issues.

With all boards unplugged except main board, do you have 5V/Vs/Va?

[ZRICE28]

Re: LG 50PC3D Power Issues.

with everything unplugged, nothing at 5v. v-a is .1 and dropping, v-s is .06 and dropping. y board and everything else plugged back in, .668 and holds at 5v, .50 at v-a and drops quickly, nothing at v-s. that is checking the pins leading to the ysus board. the smaller gauge wires at the bottom of the board that run down to where I tested dc detect, 5v is at 4.99

[tom66]

Re: LG 50PC3D Power Issues.

OK, can you locate the pin marked PS-ON and acquire a couple of 470 ohm resistors for a test that can be done?

[ZRICE28]

Re: LG 50PC3D Power Issues.

I will look for ps-on when I get home tonight. Do the resistors have to be 470s? I could pull some resistors from another board that I have laying around. Or should I stop and buy a few 470s on my way home?

[tom66]

Re: LG 50PC3D Power Issues.

Anywhere from 100 ohm to 470 ohm should be usable.

[ZRICE28]

Re: LG 50PC3D Power Issues.

I have the resistors. All I see marked on the main and power supply boards are rl-on vavs-on and 3.3v-on

[tom66]

Re: LG 50PC3D Power Issues.

Can you post a picture of the particular connector?

[ZRICE28]

Re: LG 50PC3D Power Issues.

I think this is the connector you're talking about.

[tom66]

Re: LG 50PC3D Power Issues.

OK, please connect resistor from S-5V to RL-ON and M5V-ON. You should have +5V main and other voltages like 19V available. You should also hear a click from the PSU.

[ZRICE28]

Re: LG 50PC3D Power Issues.

Like this?

[ZRICE28]

Re: LG 50PC3D Power Issues.

Same as this right?

[ZRICE28]

Re: LG 50PC3D Power Issues.

Ps stays running, but nothing on the screen.

[tom66]

Re: LG 50PC3D Power Issues.

Yes, but do you get +19V, etc.? Vs/Va should be missing for now.

[ZRICE28]

Re: LG 50PC3D Power Issues.

19.17 v, 4.94 v, v-a .093, no v-s, fan is not running.

[tom66]

Re: LG 50PC3D Power Issues.

OK, now take an additional resistor to VS ON in the same manner, do Vs and Va come up? Y-sus and Z-sus to be disconnected for now.

[ZRICE28]

Re: LG 50PC3D Power Issues.

I think I have it right. It's hard to get the resistors to stay in place in such a tight spot. The ps keeps wanting to turn off if the resistors aren't positioned just right. v-s is .033 drops slowly, v-a is .265 and drops faster, 19v is 19.19, 5v is 4.97.