Lg 60pk550

[Dortoh08]

Hello

I am looking for some help with my LG 60PK550. When I try to power it on
(remote or front panel) I hear 3 clicks from then relays on the power supply board. I called shopjimmy to inquire about repairing the PS board. I was told that it is not likely a PSB issue but it was more likely a control board or main board issue. What would your advise be on proceeding forward?

[Hamie]

Re: Lg 60pk550

Hmmm don't know how shop Jimmy could rule out the psb.

Unplug the y and z sus.

Turn on the tv. Does the power supply turn on and provide steady vs and va voltages?

[Dortoh08]

Re: Lg 60pk550

I'm not sure either. I told him the symptoms that I explained here. Either way, unplug the y and z sus boards and still the same 2 clicks then immediately after a third click. I've turned the lights off in the room to see if I can see any activity on the screen when I plug in the set and I can't see any action. The only thing I notice is the optical output on the main board lights up with the first two clicks then shuts off with the third.

[ReeceyBurger123]

Re: Lg 60pk550

Do you know how to check resistors ?

[Dortoh08]

Re: Lg 60pk550

Yes, sir. I checked the 3 large ones at the top right of the board and they were good to go.

[Hamie]

Re: Lg 60pk550

Ok so connect 5vstby and RL-ON with a piece of wire like this.

Plug in the tv. Does vs and va stay up?

[Dortoh08]

Re: Lg 60pk550

My apologies for the delayed response. I am on toddler duty today. Do you have your wire in the side that would be plugged in to the main board?

[Hamie]

Re: Lg 60pk550

Yes, unplug from the mainboard.

Look at the table on the powersupply.
And connect the corresponding points RL-ON to 5vstby.

[Dortoh08]

Re: Lg 60pk550

10-4. Will do momentarily and report back.

[Dortoh08]

Re: Lg 60pk550

Same thing, 2 clicks immediately followed by a third click.

[Hamie]

Re: Lg 60pk550

Ok so you have a faulty power supply.

During the clicks does vs or vA rise then fall?

[Dortoh08]

Re: Lg 60pk550

I checked VS and VA at the top left corner of the PS board. I assume these are the test points as they are marked VA TP & VS TP? No voltage fluctuation at all. Registers 0 volts. Let me know if I was wrong in my assumption about the test points.

[ReeceyBurger123]

Re: Lg 60pk550

Did you bridge the Vson signal ? If so have you checked all fuses ?

[Dortoh08]

Re: Lg 60pk550

All 4 fuses check good with a meter. Vson signal?

[Hamie]

Re: Lg 60pk550

You don't need to bridge vs-on. This is an LG not a Samsung.
I can assure you both vs and va will come on with RL-ON to 5v

check is IC701 shorted?

[Dortoh08]

Re: Lg 60pk550

I will check later today.

[Dortoh08]

Re: Lg 60pk550

I have the PS board back out and have located IC701. But wouldn't I need a diagram of the IC to know the configuration to determine if it is shorted? Or am I missing something? Visibly, nothing jumps out at me as being wrong.

[Dortoh08]

Re: Lg 60pk550

Ok, I tried to check ic701 for shorts. The only pin that I can tell is shorted to ground doesn't seem to be connected to a trace on the board. Does this seem correct?