LG 60PA6500 - blank picture wont boot

[skyver]

Re: LG 60PA6500 - blank picture wont boot

so bridge which ones here? Im presuming the M_ON RL_ON & STBY

[skyver]

Re: LG 60PA6500 - blank picture wont boot

The more i read LG docos i think it might be the SMPS in some way. Well the way SMPS receives from the main board

Doco says:
-------------------------------------
.."Main Board receives a “POWER ON“ Command from either the Power button or
the Remote IR Signal, it outputs a high (2.43V) called RL_ON at Pin 15 of P813. This command causes the Relay Circuit to close both Relays RL101 and RL103 "
-------------------------------------
The mainboard is sending - 2.54v


Doco says:
-------------------------------------
next step is for the Microprocessor IC1 on the Main Board tooutput a high (3.27V) on M_ON Line to the SMPS at P813
Pin 17 which is sensed by the Controller IC701, turning on the M5V line and outputs at P811 pins 9 and 10 to the Y-SUS
board.
-------------------------------------
The mainboard is sending - 3.29V

* With the mainboard removed then the floating ground on SMPS kicks in and of course relay clicks , i can do auto gen test and turn on the display etc.
* When i bridge M_ON and RL_ON im sending 5+Volts and that is causing relay to click but , continually click.

[skyver]

Re: LG 60PA6500 - blank picture wont boot

Was just thinking if I pull that floating ground pin so it isn't hard grounded, theory the relay should close when power is supplied and then power the main board, or blow up me house

[skyver]

Re: LG 60PA6500 - blank picture wont boot

And she works : )

[tom66]

Re: LG 60PA6500 - blank picture wont boot

That's surprising. I wonder why the main board "works" but won't send the power on command. Will the TV go into standby properly? (It might leave the screen glowing slightly, consuming ~60W in standby...)

[skyver]

Re: LG 60PA6500 - blank picture wont boot

That's surprising. I wonder why the main board "works" but won't send the power on command. Will the TV go into standby properly? (It might leave the screen glowing slightly, consuming ~60W in standby...)

Nope when i turned it off it went off in a way that the standby light wasn't even on the front of the TV which is wierd.
pressing power then brought on the standby light but couldnt be powered on. Had to unplug and replug power back in for it to turn on again.

So pretty much main board is knackered in some way, i can live with turning it on and off like this but it is a bit of a pain, but at least its working i guess

Ill keep going till i track down what it is thats failing, getting closer

[skyver]

Re: LG 60PA6500 - blank picture wont boot

cant find out the weird and inconsistent issues with this one

so just going to live with how it is with the floating ground floating , until i see a mainboard for my model as that still looks like the likely cause , some sort of communication issue with smps and main.

but hey the tvs working in now, powering it on and off with at the power point.(put a plastic tab over the power button on the remote so no one presses it and freaks out the TV)

cheers for all your help and info tom

[garfield-cat]

Re: LG 60PA6500 - blank picture wont boot

Hi Skyver .. I am having the same issue and found it strange that the power supply powered up va and vs with no other boards connected. Can you explain what you did to turn yours on and off? Did you ever find a main board to replace yours?

Thanks

[garfield-cat]

Re: LG 60PA6500 - blank picture wont boot

ok .. just to clear it up .. i pulled the power board thinking that was the issue as when i fisrt plug in the TV a relay clicks, 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 but the 5v was reading 2.6.

I pulled the power board and bench tested it and when plugged in with no main/control or anything connected, the relay clicked and have the same voltage readings (va and vs right and 5v = 2.6)

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

[garfield-cat]

Re: LG 60PA6500 - blank picture wont boot

when i mean what the va and vs should be I mean when powered on .. vs = 205v and va=55v

[dick_barton]

Re: LG 60PA6500 - blank picture wont boot

Is it the same as in the picture in post #21. You say you have STBY, VA, VS but not 5.2V and how about the 17V when disconnected from the main board? Is that correct.

[garfield-cat]

Re: LG 60PA6500 - blank picture wont boot

"Is it the same as in the picture in post #21. You say you have STBY, VA, VS but not 5.2V and how about the 17V when disconnected from the main board? Is that correct."

With the power supply disconnected from everything, on the plug shown in post 21, I have 17v but where I should have 5.2 I have 3.7-3.9 (won't lock steady)
and my standby voltage is only 3.7-3.9 as well