LG 50PX4R-ZB stuck in standby mode

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

The power supply produces the voltages, which come up at those outputs.
Do you hear a relay click when you press the power button?

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

Do you think it will be a power supply replacement or do you think it may be repairable ?? I cant see any indication of badcaps though??

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

I am not sure if your power supply or main board is bad now. RL ON should cause the output voltages to come up, but you are not seeing them rise? On the other hand, the power supply might be waiting for VS ON before turning on the outputs fully.

OK So the output voltages i presume go from the power supply to the main board then back to the power supply on the 19v gnd pins connector ??

But there is a possibility like you said that the power supply board is waiting for a voltage at vs ON before turning the output voltages to the main board ??

The main board does have a red led light on it ???

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

I am not sure if your power supply or main board is bad now. RL ON should cause the output voltages to come up, but you are not seeing them rise? On the other hand, the power supply might be waiting for VS ON before turning on the outputs fully.

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

Hi Tom

RL ON = 0.04V DC then switch power button on remote then 4.23V DC then back to 0.04 V DC after 10 seconds

Vs ON = 0.04V DC switch on power on remote still 0.04V DC

Thanks

It looks like you have a main board fault as it's never switching on the VS ON.

yes i did these checks before ?? and the same readings ??

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

Did you note that with your old board? Because that indicates power supply not working? Did I miss something?

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

When you press the power button, or turn the TV on using the remote, do RL ON, VS ON or anything else change?

RL ON goes to 4.25v when power button pressed then back to 0.037v

The rest the same ?

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

When you press the power button, or turn the TV on using the remote, do RL ON, VS ON or anything else change?

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

DC. Do you see any other voltages that are measuring low?

yes they are all low except STBY 5V and AC ON

AC ON = 4.338v
RL ON = 0,0037v
STBY 5V = 4.97v
Vs ON = 0.038v
5V MONI= 0v

19v = 000.8mv
19v = 1.3mv
6V = 0.1v
3.4v = 0.464v

Do you need me to take any other measurements ? thanks

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

DC. Do you see any other voltages that are measuring low?

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

I measured 19v and GND and it only measures 0.008 mV DC Should i measure in DC or AC ?
thanks

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

On the power supply.

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

Voltage measurements on the power supply or main board ??
thanks

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

Make measurements of the power supply connector, and do not rule out the chance that the board you received was defective...

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

I have only just got the part !!! It was a nightmare to get hold of this part, I eventually got one shipped from Holland !

Anyway I swapped the board over and the problem is exactly the same !!!

Can anyone please help ????

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

Problem is, the 42" and 50" use same boards; the only difference is software on the boards.

Hi Tom

i have another question ???

When you say the only difference between 42" and 50" is the software ..... is it easy to install the 50" software to the board ?? If so how is this done .... I am presuming it is from the RS232 port on the board ??

thanks again ste

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

There may be differences between those boards due to production changes, which has nothing at all to do with 50"/42".

Hi Tom

I am still stuck with the LG TV !!!!

I have still not been able to find the part

However Do you think it is possible to use the AV board from a LG50PX4D

They are the same except the Audio Outs are on different sides ??

I thought i could also use the back cover of the LG50PX4D so then the holes would match up on the back ??

What do you think ?

thanks ste

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

There may be differences between those boards due to production changes, which has nothing at all to do with 50"/42".

It looks like it is back to the drawing board !!!

The shop in Italy selling the part i thought i needed has replied back and told me it is for a 42"

It looks like the 50" main board i need is going to be hard to find !!

thanks again Tom for all your help ... wish me luck !!

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

There may be differences between those boards due to production changes, which has nothing at all to do with 50"/42".

mmmm ok !! So there are also boards with 4 smd capaacitors and the connector for the 42" also ??

mm i didnt realise how difficult it would be in getting parts ??

Do you think i should get this board ??

thanks

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

There may be differences between those boards due to production changes, which has nothing at all to do with 50"/42".