LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

[ricoscoro]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Well, a happy ending on this...

The new board came in. Installed it in the unit.. The power button seemed to work, but when I turned it on, nothing on the screen..

Sum beach!!!

Checked the ribbon cable going from the main board to the Control Board.. Some of the teeth were not aligned properly...

Straightened them out, plugged it back in and viola'

Thank to all who contributed... VERY much appreciated..

Where did you get your main board from?
Was it the control board or the main board that was the real culprit?

I have an LG 50PK750 that after a brief (1 second) power outage while it was running, decided to start turning itself off after about 10 minutes. If you try powering it back up it just turns on the power light but after about 10 seconds shuts off. If you wait about 30 minutes and power it up again it runs fine for about 10 minutes and then shuts off.

We tested the power board and it looks like a diode by the voltage regulator is bad and we we re-soldered several points on the board that looked like they had minor cracks in them. Have not ordered a new diode yet and figured we would order a voltage regulator as well to be safe.

Any suggestions for this issue?

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Well, a happy ending on this...

The new board came in. Installed it in the unit.. The power button seemed to work, but when I turned it on, nothing on the screen..

Sum beach!!!

Checked the ribbon cable going from the main board to the Control Board.. Some of the teeth were not aligned properly...

Straightened them out, plugged it back in and viola'

Thank to all who contributed... VERY much appreciated..

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Well, at least we know that problem IS the main board..

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Oh carp!!!!

It's always in the details!!!

[selldoor]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Nooooooo! I also mentioned bar code label - your new board is off a 42 inch set

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

That may not be the end of the problem- is the board for the same panel make and size ??
eeprom and drivers are a bit choosy!

Yous should also be getting sound if connected to a source

Yea, the board numbers are identical..

I do get the static sound, but haven't hooked it to a source yet..

[selldoor]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

That may not be the end of the problem- is the board for the same panel make and size ??
eeprom and drivers are a bit choosy!

Yous should also be getting sound if connected to a source

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Got the replacement board in..

As the saying goes, there is good news and bad news...

The GOOD news, it appears to fix the problem. The TV now comes on. I hear the static sound of an unconnected analog channel..

The BAD news is, I did not heed Selldoor's advice as well as I should have... The boards are NOT 100% identical..

The lower board is the old one. It has the tab style connector that goes to the Video...

The upper board is the new one. It has the plug in connector.

But it does show that the Main Board was the issue.

Unless anyone knows of some kind of adapter, I have an AOYUE 968. I am going to use that to pull the proper connector off the old board and place it on the new board..

Needless to say, it's going to be delicate...

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Realistically I can see no alternative- Make sure it is EXACTLY the same numbers on the Bar code label and for the same size screen. Perhaps get an indication as to if it can be returned if it dont work. We still dont know if the surge got through to ysus/zsus boards
and buffers. I did wonder if you could just apply 5v from another source to the M-ON
would anything else start up/break. Need input from a plasmaman

What's the worst that could happen??

Iffn yer bored today, I would love to get yer insight on this one..

https://www.badcaps.net/forum/showthread.php?t=42835

That one's a little different. I get power and tone, but no picture.. All the voltages check out and I replaced the Control Board.. Still nada...

[selldoor]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Realistically I can see no alternative- Make sure it is EXACTLY the same numbers on the Bar code label and for the same size screen. Perhaps get an indication as to if it can be returned if it dont work. We still dont know if the surge got through to ysus/zsus boards
and buffers. I did wonder if you could just apply 5v from another source to the M-ON
would anything else start up/break. Need input from a plasmaman

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

I can pick up a replacement board for $30... Wonder if that's going to be my best option..

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Guess you were just hoping it was the problem

Yea, woulda been nice..

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Q301 and Q302 have no shorts.. IC302 has no shorts..

I am going to check all the R3xx resistors, but there is a buttload of them...

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

"by jove i think hes got it"

I don't need a ton of bricks to fall on me!!!

Well, not ALL the time anyways..

[selldoor]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

ok... According to this datasheet...

http://pdf1.alldatasheet.com/datashe...85s-3.3tr.html

... It's, from left to right..

Adj/gnd output input

hopefully, i didn't frak it up by measuring it the other way..

Anyways, it appears to check out..

"by jove i think hes got it"


Guess you were just hoping it was the problem

[selldoor]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Hmmmmmm Based on the new links you gave me, it's possible that the connections are not INPUT GND OUTPUT but rather GND INPUT OUTPUT

Here are the pics assuming the former..

No thats not right either AND you are doing the test wrong
How to test a voltage regulator

Testing a voltage regulator requires a digital multimeter. The test is simple and easy to perform. Note: Voltage regulators are typically "low" voltage. Most are 5V DC or less so there is little danger of you getting shocked, but as always, exercise caution when measuring power.

To test a voltage regulator (circled in red),

1) Set your multimeter (if manual range) to 20V DC or DCV for autoranging.

2) Put your black probe on a ground screw (circled in black). Leave it there the entire time. This is your ground.

3) Put your red probe on each of the pins including any "cut" or "stub" pin, but ignore the "fat" tab. The fat tab is "up" or "north". Number the pins left to right.

4) Report them like below along with the part number (include all lines on the IC) of the IC. Don't report "they all tested good". About once every 2 weeks, we get someone who reports that only to find out they did the arithmetic wrong or mis-interpreted the results. So report all the readings.

U100 -> pcb designation
AS1117-33 -> line 1 of the IC
0506 -> line 2 of the IC
pin 1 = 0.000
pin 2 = 3.301
pin 3 = 5.001

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Here is the datasheet
http://www.datasheetlib.com/datashee...html#datasheet

I do notice solder balls between the traces - try brushing them off with a
fine wire brush or similar.

Looks like we were on the same page

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

OK... According to this datasheet...

http://pdf1.alldatasheet.com/datashe...85S-3.3TR.html

... it's, from left to right..

ADJ/GND OUTPUT INPUT

Hopefully, I didn't frak it up by measuring it the other way..

Anyways, it appears to check out..

[selldoor]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Here is the datasheet
http://www.datasheetlib.com/datashee...html#datasheet

I do notice solder balls between the traces - try brushing them off with a
fine wire brush or similar.

[Michale32086]

Re: LG Plasma 50PK540 Lightning Victim LED Light Relay Clicks On Plug In Nothing Else

Hmmmmmm Based on the new links you gave me, it's possible that the connections are not INPUT GND OUTPUT but rather GND INPUT OUTPUT

Here are the pics assuming the former..