LG 42PA4500 mainboard LED codes

[DeniS182]

HI all,
I have this TV , without picture,sound.. only LED on mainboard blinking all the time : 1 second blink, then 5 second nothing and then again 1 second blink and again, again...
Have someone blink code table or something like that? Thanks for answer.

[tom66]

Re: LG 42PA4500 mainboard LED codes

Is that on control board, or on actual main board (with HDMI ports, etc.)

[DeniS182]

Re: LG 42PA4500 mainboard LED codes

It's on mainboard , board with all connectors like hdmi, scart etc.
Led on front panel is turned off and nothing changed when I pushed start button or other buttons ..

[tom66]

Re: LG 42PA4500 mainboard LED codes

I've never seen led like that on a newer LG plasma. It's not optical port or for Ethernet?

[DeniS182]

Re: LG 42PA4500 mainboard LED codes

It's not optical port or for ethernet.. I attached some photos.

[tom66]

Re: LG 42PA4500 mainboard LED codes

OK, what you can try and do is jumper the two holes marked EXT AUTO GEN on this board:
https://www.badcaps.net/forum/attach...1&d=1421777971

And disconnect LVDS (right most ribbon connector)

Then plug TV into mains power.

Do you get a sequence of test patterns appearing on the screen?

[abdekader]

Re: LG 42PA4500 mainboard LED codes

i have the same TV check the Y-sus IGBT transistor shorts , but after i change it the same transistor shorts , this problem to me in all of kind of LG PLASMA Y-SUS T KIND
something problem in it
check 18v in Ysus

[DeniS182]

Re: LG 42PA4500 mainboard LED codes

tom66: I jumped these two holes and disconnect lvds cable too (ribbon cable with blue end), but nothing.. no picture. But LED on mainboard was off and LED on front of TV was ON and when I push start button , then this led turn off and again turn on and stay ON.
abdekader: I'll check it tomorrow.

[DeniS182]

Re: LG 42PA4500 mainboard LED codes

I didn't have time to work on this sooner.
Now I measured components on heatsink, on YSUS and some are short circuited. I can ask you how to remove board from tv? I unscrewed all screws, but I have problem with three connectors. I don't want damage it. Any idea to remove it without damage connectors / board?

[drussell]

Re: LG 42PA4500 mainboard LED codes

It can take a fair bit of pulling force, yeah...

I generally use a pair of needlenose pliers, opened slightly and twist between the buffer board and the Y to help pry them apart while pulling. This is much kinder to the edge of the board than a screwdriver, for example, since the outside of needlenose pliers are generally rounded. Just be gentle and take your time.

If there is a spot that has the little protrusions from where the boards are snapped apart during manufacture and you need to pry them apart, do it there since it gives a bit of added protection to the edge of the board. If you ever run across ones that are really tight or have many connectors you can always shim in a little plastic against both boards when you stick something in there to pry them apart.

[DeniS182]

Re: LG 42PA4500 mainboard LED codes

drussell: thank you for advice.
I found three short circuited components. First on heatsink Q709 - KF7N60 (N channel mosfet), second and third on bottom of pcb both in DPAK package. And I don't know what they are. You can see on photo of bottom PCB - eight components in dpak in a row and first and last are these short circuited. On first is written JF63K2 A3P 02 and on last is written F2A A1P 069. Have someone service manual/schematic of this TV or can help me with identification of these burned-out components? thanks for answer.

[DeniS182]

Re: LG 42PA4500 mainboard LED codes

I can't find schematic of this YSUS board. Can you help me?

[jamesb6]

Re: LG 42PA4500 mainboard LED codes

I have one of these sets as well. It has the exact same behavior as DeniS182 tv. I have also found shorted components on the YSUS but my board has different ones shorted. My shorted FETs are Q734, Q735, Q736 and Q737. Two on the under side and two on the heat sink.

I suspect a new YSUS is the fix. Any advice?