Lg 42pj350

[sekino]

I have clicking sound when turning ON tv, red light goes off and on. When I disconnect white cable from the left side of power board the tv stays ON but of course no picture. Anyone knows where can be the problem?

[sekino]

Re: Lg 42pj350

I have replaced on power board:
2x 5W22R Vertical Ceramic Resistor
1x 3BR1565JF
but that not helps this time, but works fine with my LG 50pk350.

I have no backlight and can hear buzz sound when turning on tv for a second.

[sekino]

Re: Lg 42pj350

Meanwhile I've measured voltage on power board on the connector to the Y-sus board with disconnected Y-sus board:
VS - 205
VA - 60
M5 - 5

and on the connector bottom right:
17V - 17
5V - 5
STB - 5
AC DET - 4.1
AUTO GND - 3.2

what else should I troubleshoot?

the buzz sound is going from center of the y-sus board.

[Alastair E]

Re: Lg 42pj350

You have a fault on one of the 'SUS' boards.

Re-connect the PSU plug, remove the plug from X-SUS and re-try.
--If PSU stays on--fault is on the X-SUS. If just the same--fault is on Y-SUS.

[sekino]

Re: Lg 42pj350

hopefully i get your point right, please look at my picture attached:
1. if I disconnect plug from power board to Y-sus board (yellow rectangle) the tv stays ON
2. if plug from Y-sus board is connected but i remove plug from X-sus board (red rectangle) the tv is turning off and on.

I assume now that Y-sus board is faulty, what can I check on this board?

[Alastair E]

Re: Lg 42pj350

Ah--But.....

Isnt the PSU plug going To the Y-SUS and the X-SUS thick wiring going TO the Y-SUS?

So--You would need to test as I described.

Power first goes to Y-SUS from there it goes to X-SUS.......

[sekino]

Re: Lg 42pj350

I don't get it. Please look at my picture.
1. First I disconnected plug 1 > TV stays ON
2. Then I reconnected plug 1 (that means all plugs connected) > tv turns off and on.
3. With reconnected plug 1 (that means all plugs connected) and disconnected plug 2 > tv turns off and on.

If I should test something else please highlight it on my picture.

Thank you very much.

[Alastair E]

Re: Lg 42pj350

OK so.....

Short or fault on Y-SUS board, probably on the Vs supply.....

Set Unplugged from mains, and PSU plug (1) unplugged, what resistance to chassis do you get on the pins marked Vs of the Y-SUS board plug?

[sekino]

Re: Lg 42pj350

I measured resistance with unplugged plug (1), see picture.

[Alastair E]

Re: Lg 42pj350

OK--so no obvious shorts then.....

How about if you disconnect the buffer-board from the Y-SUS and re-try with all plugs back in?

[sekino]

Re: Lg 42pj350

Not sure which plug to disconnect, hopefully ot's one in bottom left corner o Y-sus board (red square on picture) or something else?

[Alastair E]

Re: Lg 42pj350

Not quite.....

The long green panel on the left is the Buffer-board. As I recall--there's a row of screws that connect the buffer to the Y-SUS where they overlap.

You'll need to remove all those screws, and separate the boards so there's a small gap between the boards as well as that small white flat lead--Then re-try.

[sekino]

Re: Lg 42pj350

I've disconnected flat lead and unscrewed almost every screw and left 0,5cm gap between boards, nothing changed, tv turns off and on.

[tom66]

Re: Lg 42pj350

Bad Y-sustain. Common fault with these models. A repair kit might be available but you also might have to swap whole board...

[sekino]

Re: Lg 42pj350

what parts are in repair kit, I would like to find out what is wrong, rather than changing the whole board.

[Alastair E]

Re: Lg 42pj350

As there's no obvious shorts, I would start looking around the DC-DC converter stage at the bottom of the board.
(No supplies from this, I would expect the set to shut down)
Check the IGBT's/MOSFETS and diodes on the heatsink anyway for any leaks/shorts....

[sekino]

Re: Lg 42pj350

I've checked resistance on all black caps and green things (sorry I'm not technician ) can you please mark on my picture what everything should I check? I'm desperate. I don't know which one is DC-DC converter etc... Thank you very much

[Alastair E]

Re: Lg 42pj350

TBH--I think in your case, the replacement of the complete board would be the best solution.

Some knowledge of the different parts, how to test them and correctly interpret the results is needed, as well as the skill and tools to safely remove and re-fit the parts without damage.

The DC-DC Converter--Isnt a single item, but on that board is probably 20 or 30 parts make it up--Any one of those parts could be faulty--Or not!....

--They are around that square yellow thing at the bottom (Transformer)

[sekino]

Re: Lg 42pj350

OK, do you have any links for cheap YSUS board EAX61332701 from Europe or China... ???

[sekino]

Re: Lg 42pj350

I bought new YSUS board from eBay and tv works like a charm. Thanks