Lg 42pn5400 won't turn on

[Malachi]

I haven't been on in a while. I picked up a free lg 42pn5400 that shut off during a storm.
I had a working psu for it so I swapped it out. Tv won't turn on. Only the red standby light is on.
I've disconnected the mainboard from the control board and jumped the pins for test patterns but the screen stays black. No change to the standby led.

I've forgotten a lot of what I had learned. Any help?
Could it still be the main board if there are no, test patterns.

[maxvalutech]

Re: Lg 42pn5400 won't turn on

Sounds like y or x problem screen not lit etc you need the voltages check and jumper PSU with main disconnected I.e pson vson to see if screen lights, briefly disconnect y side is vs up on psu . I've got a PJ and a PG in front of me now and yes takes awhile to recall the steps to follow.

[Malachi]

Re: Lg 42pn4500 won't turn on

It's the main board. It wasn't enough to disconnect the lvds cable from the main board to the control board. I disconnected the power cable from the psu to the mainboard.
Once I did, I got test patterns.

[maxvalutech]

Re: Lg 42pn5400 won't turn on

Well done. On the PG I only had to take out lvds as otherwise PSU wouldn't start without jumpers. I've got a 60PV with no pic to work on when I manage to wrestle it to the table - more self abuse I think !!!