LG 60PA6500 - won't turn on

[garfield-cat]

I have an LG 60PA6500 that will not turn on.
When I fisrt plug in the TV a relay clicks and the red led on the from comes on and then nothing. Nothing when pressing the power button or using the remote.

I tested the power going to the Y and Z boards and got va and vs power reading as they should (vs = 205v and va=55v) but the 5v was only reading 2.6.

I pulled the power board and bench tested it (nothing else connected to it) and when plugged in the relay clicked and have the same voltage readings (vs = 205v, va=55v, 17v=17v but 5v and stand-by =2.6).

I am curious why this board is staying powered up on va, vs and 17v with no logic board or main board attached to it and why 5v and stand-by is only showing 2.6v

I m not sure where to start with this one. Any help is appreciated. Thanks

[maxvalutech]

Re: LG 60PA6500 - won't turn on

I would test for the 5v from source to output connector to find where it drops then when 5v is at output th3 main should activate. Possibly resistor/s on the feed circuit gone a bit high.

[garfield-cat]

Re: LG 60PA6500 - won't turn on

thanks. I have no idea where to tell where to find the "start" of the 5v. Any ideas?

[maxvalutech]

Re: LG 60PA6500 - won't turn on

With standby on your power board is "idling" to save on electricity but there should be voltage around 160v as measured between two legs of big capacitors rated 450v. From that section the 5v is derived and when power on is executed this voltage signal is sent to main board which responds then to ps-on basically saying "Ok I'm good let's go" and the power supply then switches on all the other voltages. If your Va etc is on then the Ps-on must be picking up a voltage from somewhere on the power board. Try to find a schematic for that board by maker and model number of the board itself. Holding the board up to a light source eg sky you can sometimes see where what goes. If you are fairly certain the power board is faulty perhaps shopjimmy site may have a fixit kit or replacement. Here in Oz I usually look to China via aliexpress site. Pay the price and take your chances type of thing but at least plenty of compatible spares with two boards from which you may make up a good one if both had a problem

[garfield-cat]

Re: LG 60PA6500 - won't turn on

Thanks .. I'll keep poking around and see what I can find out. I was thinking of ordering a new power board but wanted to be 90+% sure it was that before I dished out the cash for a new one.

[garfield-cat]

Re: LG 60PA6500 - won't turn on

OK .. I decided to poke around a bit and display all the voltages. I really can't figure this one out and really need your help. EVERYTHING looks right and can't understand what is going wrong.

The attached pictures show all the voltages on the connectors.

As soon as I plug in the board when bench testing it the relay clicks and all voltages are present. With the board in the TV, the red light on the main board is on , the green light on the logic board flashes green and the light on the front of the TV is on (red) .. but the screen does not come on and all buttons on TV and remote do nothing.

I am not sure about what I am suppose to have on connector P813 (with the error_det, ac_det, etc).

Hoping someone can help as I don't want to buy a new power board if it is not the faulty board.

Thanks