LG 50PX4R-ZB stuck in standby mode

[surferbum]

Hi

Im new to "badcaps" and this site helped me fix my samsung tv last week !! I have now decided to put my HNC in electronic electrical engineering to good use and start fixing tvs !! well try anyway
I know a bit about electronics but no way near as much as you pro's on this site ....
Anyway .....I have a problem with an LG 50PX4R Plasma TV, The fault is that it reverts back to standby mode : this is what happens -
1.the red light comes on
2.press power on remote
3.relays on power board clicks
4.goes to orange light
5.goes back to red light
6.black screen as if in standby mode

I thought it would be a quick fix by seeing a bad capacitor BUT i cant find one?
However I dont have my capacitance meter YET only my multimeter ( i have bought one it s been delivered this week)
I did see what looked like a leaky SMD capacitor on the board where all the ribbons come off. It looked like bird poo had spirted out of it ???
The values on the SMD where:
Y1352
100
16F
I presumed this was a 100uF / 16V with F been the tolerance ?

the shop didnt have 16V so I got a 100uF/25V

Replaced but problem still persists.

Also on this board with the chips and ribbons it had a red led light on the board ? If that is normal ??

Any help would be gladly appreciated

I will take pictures of the back of the tv and capacitor tommorow when i get back from work !!

thanks guys

[cadiman]

Re: LG 50PX4R-ZB stuck in standby mode

ipm chips on the y board most common failure.

troubleshoot y board by unplugging main power feed cable going to y board.

power supply should come on and stay on when powering up tv again.

to reset from protect mode just unplug the tv and plug it back in. (ac in)

On this model the cable for the z board may feed off of the y board.

There are plenty of l/g threads on this forum.

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

ipm chips on the y board most common failure.

troubleshoot y board by unplugging main power feed cable going to y board.

power supply should come on and stay on when powering up tv again.

to reset from protect mode just unplug the tv and plug it back in. (ac in)

On this model the cable for the z board may feed off of the y board.

There are plenty of l/g threads on this forum.

Hi ... Thanks for the reply. Sorry for the delay I have been workibg away and not been getting home until late.

I have unplugged the main power feed (4 pin connector) to the YSUS board and the problem still persists.

I also unplugged the other power cable with Vs on (10 pin connector) to the YSUS board and also the problem still persists ??

On power up still get the red lightm press power on remote, goes to orange light and clicks .... then after about 7 seconds goes back to red light. If i then press power on the remote again it does the same EXCEPT it does not click ?? It only clicks when i unplug it and plug it back in ??

Do you think it might be the main board ??

thanks

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

Can you post pictures of your power supply. I've had AC detect issues cause this problem.

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

Can you post pictures of your power supply. I've had AC detect issues cause this problem.

Hi Tom

ThAnks for your reply...... I have attached some pictures... i hope they are ok... I took them on my samsung s2 so they are normally pretty clear ?

Thanks for your help tom

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

This photo:
https://www.badcaps.net/forum/attach...9&d=1371677416

Bottom of the board, is that all of the connectors installed? Those positions unused?

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

Hi Tom

Yes that is all the connectors installed/ how it was when i opened up the back of the tv ?

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

OK, along those connectors do you see a point marked AC-DET, AC-DETECT, or AC-D?

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

OK, along those connectors do you see a point marked AC-DET, AC-DETECT, or AC-D?

Hi Tom

No it doesnt ? This is how they are marked ......

Top 8 PIN connector NOT CONNECTED
GND/GND/GND/GND/3.4V/3.4V/3.4V/3.4V

Left 7PIN conector CONNECTED
AL ON/RL ON/ STBY 5V/GND/VsON/5V MONI/POD

Middle 12 PIN connector NOT CONNECTED
3.4V/3.4V/GND/GND/6V/6V/GND/GND/12V/12V/GND/GND

Right 10 PIN connector CONNECTED
19V/19V/GND/GND/9V/GND/3.4V/GND/12V/GND

hope this helps

thanks

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

AL ON possibly AC ON instead?

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

AL ON possibly AC ON instead?

Yes AC ON sorry about that !!!

I can do some checks tommorow after work if you need to know any other information which may help ?

Thanks

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

Hi Tom

I dont know if this will help ?? As previously mentioned i replaced an SMD capacitor 100uF 25v on the control board. I bought it from maplins and is a little bigger than the old one ?? Here is a link of the control board and the SMD i replaced is the one near the middle near the bottom ( closest one to the big chip in the middle )

Hope this helps ...........thanks

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

http://www.ebay.co.uk/itm/6870QCC113...item4173bc18eb

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

We can look at the cap later, for now let's rule in or out AC ON. Measure the AC ON voltage on your meter on the 20V DC range. Red probe on pin. Black probe on chassis. Turn set on. Voltage should stay at >3VDC. Does it?

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

Hi Tom
I will check the voltage when i get back from work.

Thanks

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

We can look at the cap later, for now let's rule in or out AC ON. Measure the AC ON voltage on your meter on the 20V DC range. Red probe on pin. Black probe on chassis. Turn set on. Voltage should stay at >3VDC. Does it?

Hi Tom

I checked voltage accross AC-ON and chassis and it measures 4.3V DC
When I turn the TV on for the first time it clicks and goes down to 4.29V DC
Then back to 4.3V DC

Is this voltage too much, it does not stay below 3v DC ?

Thanks

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

That voltage is fine. >3VDC means voltage should be more than 3VDC.

Can you check RL ON and VS ON too?

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

That voltage is fine. >3VDC means voltage should be more than 3VDC.

Can you check RL ON and VS ON too?

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

[tom66]

Re: LG 50PX4R-ZB stuck in standby mode

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

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

Thanks Tom

Is this something I can fix or is it a replacement board ??

Is the model number on the the white sticker with the voltages on ? E247691

Thanks