LG 42PQ3000 Plasma TV Not Starting (clicking relay)

[safesurfer65]

Hello all

I've got a LG 42" plasma TV (42PQ3000) that won't start. Relay clicks for about 30 seconds with a red flashing standby light. I've isolated the X & Z sus boards with the same problem. Upon closer inspection I noticed a fried diode (highlighted in red) which I removed for identification (1N4007). Is it likely the IC (W6252) beside the dead diode on the heat sink is also faulty and is there and easy way of testing with a multimeter. Thanks for the help.

Mark

[Moreno83]

Re: LG 42PQ3000 Plasma TV Not Starting (clicking relay)

I got the exact same problem but my diode is not the problem....
Im going to test the 22 Ohm resistors this afternoon see if they are ok.

Btw my led is not flashing , it stays on but relais keeps clicking.

[safesurfer65]

Re: LG 42PQ3000 Plasma TV Not Starting (clicking relay)

Yes I tested the 2 x 22 Ohm resistors at the top of the board and they tested ok.

[tom66]

Re: LG 42PQ3000 Plasma TV Not Starting (clicking relay)

Start checking if the standby rail, 17V, Vs and Va are working.

[safesurfer65]

Re: LG 42PQ3000 Plasma TV Not Starting (clicking relay)

Hi Tom

Thanks for the help again. I'm getting 5v on the standby pin, getting no power at all on both the 17v pins when switched on. Can't see the VA and VS test points, can only see the VA and VS adjusters ?

thanks

Mark

[tom66]

Re: LG 42PQ3000 Plasma TV Not Starting (clicking relay)

Check Vs/Va at connectors to Y-sus...
Check all fuses on PSU board.

[safesurfer65]

Re: LG 42PQ3000 Plasma TV Not Starting (clicking relay)

All 3 fuses on PSU good, fuse on Y-Sus good. No voltage at all on both VS and VA on the Y-SUS connection when switched on.

thanks

[tom66]

Re: LG 42PQ3000 Plasma TV Not Starting (clicking relay)

Check the control signals from the main board then, see if it's sending the turn on command (VS ON, RL ON, M5V ON etc)

[safesurfer65]

Re: LG 42PQ3000 Plasma TV Not Starting (clicking relay)

Getting very erratic readings

In the off position

STBY_5V ranges from 0.5-3.5v
KEY_ON ranges from 4.3v-5v
M5V_ON 0v
VS_ON 0.0v
RL_ON 0v

In the on position

STBY_5V ranges from 1.8-3.9v
KEY_ON 0.3v
M5V_ON ranges from 0.05 0.1v
VS_ON 0.0v
RL_ON ranges from 0v-2.4v

[tom66]

Re: LG 42PQ3000 Plasma TV Not Starting (clicking relay)

The bouncing STBY 5V should be investigated.

[marty_cam]

Re: LG 42PQ3000 Plasma TV Not Starting (clicking relay)

Hi. I know this is an old post but I seem to be having the same problem on the abovementioned model.

On power on the loud clicks are very noticable and the LED area around the power button just flicks red this eventually dies completely after a minute or so and just seems unresponsive after that (until powered off for a few minutes), then it's back to the clicking...

I don't want to spend money on a new (or even refurbished power board) if that will not solve the problem and I don't mind replacing certain components on the board, if I'm given some help in doing so. My soldering skills are decent enough as I've replaced small IC's and Caps etc on boards before but alas, the only equipment I have is a multimeter and Soldering iron.

Any help would be much appreciated.... as the learning would also be beneficial in learning a little more on electronics...

cheers,

Marty (Ireland)