LG 50ps3000 power fault

[Mr.deep]

Hi guys

I'm currently looking into a power fault, where when the main board is connected the dc relays don't hold in and power to the rest of the TV fails.

When I disconnect the main board the power Is distributed around the TV (I think In my basic knowledge) as normal.

Would I be correct in replacing the main board or could there be more to it than that?

Many thanks

[Hamie]

Re: LG 50ps3000 power fault

The power supply won't power on without the mainboard.
You'd need to jump it on.

Run test patterns with the mainboard disconnected.

[candy-men]

Re: LG 50ps3000 power fault

Try to disconnect the both PCBs: ZSUS Board (Right Side) and YSUS Board (Left Side). If You Power on now, and the Relais is still holding, than you know that the Fault is somewhere there. Measure tzhe Voltages on the Connectors, explicit VS and VA. They should be there if the Power Board work properly.

[Mr.deep]

Re: LG 50ps3000 power fault

The power supply won't power on without the mainboard.
You'd need to jump it on.

Run test patterns with the mainboard disconnected.

Thank you.. But I think u misunderstood?
It's only when the main board is connected that the power shuts down, I think maybe due to an overheat cut out because I can't then power up at all until some time has passed.

When the main board is disconnected the power on the board is fine, 5vdc to all points and relays hold in..

[Mr.deep]

Re: LG 50ps3000 power fault

How can I jump the board please?

[Mr.deep]

Re: LG 50ps3000 power fault

The power supply won't power on without the mainboard.
You'd need to jump it on.

Run test patterns with the mainboard disconnected.

Can you help me powering up the TV with the mainboard connected and running the test please

Many thanks

[Mr.deep]

Re: LG 50ps3000 power fault

Try to disconnect the both PCBs: ZSUS Board (Right Side) and YSUS Board (Left Side). If You Power on now, and the Relais is still holding, than you know that the Fault is somewhere there. Measure tzhe Voltages on the Connectors, explicit VS and VA. They should be there if the Power Board work properly.

As long as the main board is disconnected everything else connected will power up.. Apart from the screen. But the Voltages travel to the other boards.

[Mr.deep]

Re: LG 50ps3000 power fault

So I disconnected everything from the power board, switched the power on, and u can here the relays kick in and then drop out.

Connected everything except the main board, switched it on and again they click and then drop out, as above.

Then I disconnected everything, connect the the main board, switch on, and nothing happens.

Now even when the main board disconnected nothing will happen even with the relays until about 10 minutes has passed..

[Alastair E]

Re: LG 50ps3000 power fault

Hmm--

WHICH board are you Calling the 'Mainboard'....?

Set WONT Power-On WITHOUT the (Real) mainboard connected!

Real mainboard has Antenna socket and all the other inputs on it....

[Mr.deep]

Re: LG 50ps3000 power fault

Hmm--

WHICH board are you Calling the 'Mainboard'....?

Set WONT Power-On WITHOUT the (Real) mainboard connected!

Real mainboard has Antenna socket and all the other inputs on it....

Hi Alistair, the 'main board' I'm referring to is the board with the hdmi/scart etc on it...

[Alastair E]

Re: LG 50ps3000 power fault

OK--And you reckon the set is powering up--without it?

--It Shouldn't as far as I know....

[Mr.deep]

Re: LG 50ps3000 power fault

OK--And you reckon the set is powering up--without it?

--It Shouldn't as far as I know....

When the y sus is connected the relays stay in,
I'm getting readings from the bridge rectifiers. Theres 5vdc on the pins to the YSUS ... Leds flashing on the ctrl(?) board.

Once I take out the YSUS, the relays drop and everything dies.

But regardless of what is plugged into the power board, as soon as the main board is connected, everything dies, and won't come back on until about 10 minutes after the main board has been disconnected...

[Mr.deep]

Re: LG 50ps3000 power fault

Power board fault maybe??

[Mr.deep]

Re: LG 50ps3000 power fault

Anybody??

[ReeceyBurger123]

Re: LG 50ps3000 power fault

So with Ysus unplug you get Vsus voltage ?

[Mr.deep]

Re: LG 50ps3000 power fault

With YSUS and ZSUS unplugged it's not holding on. With the left board plugged in only (YSUS) I was getting 196vdc. With the right board (ZSUS?) plugged in only it was giving me same 196vdc at first but now it isn't and the relays aren't holding in.... So I plugged in the main board and it all tripped out

[Mr.deep]

Re: LG 50ps3000 power fault

Is anyone making sense of this problem?? I would love to get to the bottom of it but I'm out of my depth here....

[steved271]

Re: LG 50ps3000 power fault

can i ask a few questions.....

when everything is plugged in do you get the red standby light?
when you press power on/standby button does nothing happen(red light doesnt change state)?

sounds similar to an issue i had with my old philips BDS42V, it turned out to be a Voltage regulator on the standby line..... When i unplugged the connector that fed back the to the stanby line, my Plasma would power up, but obviously no signals from mainboard......

Not sure what the voltages were exactly but i remember that input voltage was 5v and output was 1.2 or something like that... when i replaced it the voltage on the output came back up to 1.8v as far as i can remember, this may not be your issue but your initial post is a little confusing.....

[Mr.deep]

Re: LG 50ps3000 power fault

Thanks for responding Steve.

No standby light comes on at all when everything is connected.

Basically when the main board is connected it's like an overheat devise is triggered but I can't see where that is, and then basically the TV will not do anything for approximately 10 after the main board has been unplugged (I'm assuming the overheat is cooling)..

Hope that helps

My number is 07506690823 if anyone can talk me through some trouble shooting.

Thanks

[steved271]

Re: LG 50ps3000 power fault

can you get some pictures of the boards.... then some pictures of the connectors... freferably showing the pin values... maybe there is a legend for them near to the connectors.... If you have no standby/power light at all then i would assume that something on the powerboard has failed..... so that is the first place i would look and check where all the voltages are.... Once we have pictures we can ask you to take readings from for specific pins and work out from there.... i am happy to call you and talk you through the things i would do but i cant without a visual representation of what i/you are seeing first...