LG Plasma 50PA5500

[Fletch]

Re: LG Plasma 50PA5500

I do, and when I get some time and resistors this weekend I'll go through the testing steps mentioned in this thread. I didn't feel it necessary to start a new thread without completing all the recommended tests first. I was just curious about the board codes in the meantime.

[capkid]

Re: LG Plasma 50PA5500

Check your sustain voltages:

Y-Sus: VSC, -Vy <---There should be two resistors near the edge of the board that are labeled VSC and -Vy (locations R273 and R272). Place your leads according to the + and - markings to check each of the voltages. Note: This is based on a EBR73763201 Y-Sus. If your Y-Sus is different, your test points may be in a different location.

Z-Sus: Vzb (Zbias) <-- Resistor @ location R412 based on EBR74306901 Z-Sus. Again, if your sustain is different for some reason, the location may not be the same.

[Fletch]

Re: LG Plasma 50PA5500

Thank you capkid. I did get a thread started. I will check those voltages and post in my thread shortly.

[Fletch]

Re: LG Plasma 50PA5500

https://www.badcaps.net/forum/showthread.php?t=31394

[Boogie2004]

Re: LG Plasma 50PA5500

I meant that the screen glows slightly when powered, but in this case, it apparently does not. In which case you will need to make two jumpers on the power supply to turn it on. You will need to acquire some resistors with leads ("through hole resistors.") Any value from 100 ohm to 470 ohm is usable, but lower is better.

There is a grid of pins on the power supply. The connector must be unplugged on the main board end (the board with video inputs) and left connected to the power supply.

Resistor must be connected between STBY and M_ON and STBY and RL_ON; the jumper on the control board should also be present and the appropriate cable unplugged too.

Then the screen should come on and show test patterns if it is a main board issue, otherwise it may be a power board, sustain board, or other fault.

Tom,
Hi. I am new here but I am having the same problem. I tried the jumper and the 2 resistor but the tv will just click and then another click. Nothing on the screen. How will I know if its a power supply? Thank you.

[tom66]

Re: LG Plasma 50PA5500

Do you have Vs & Va from your power board?

[Boogie2004]

Re: LG Plasma 50PA5500

Good evening Tom. I will look at the old threads on how to measure that Vs & Va. I will try it tomorrow and will let you know the result. Thanks

[Boogie2004]

Re: LG Plasma 50PA5500

With the meter on 200V, main board plugged
Vs= 9.8 -11
Va= 0
With main board unplugged
Vs = 4.4 - 6.0
Va = 0

[easternversant]

Re: LG Plasma 50PA5500

Those tests with the resistor jumpers in place? If so, bad PSU is likely the cause.

Quick question: Should we be testing the VA and VS with the resistor jumpers in place when we remove the boards? I get basically no reading with everything attached. However, when I disconnect the z-sus from the power supply or disconnect the Y-sus from the z-sus I get about the right numbers if I immediately test, but I can watch the values rapidly diminishing. Tests are with a digital voltmeter at 200V.

Any ideas anyone? Power supply?

[easternversant]

Re: LG Plasma 50PA5500

Also, I know that this is a bit of thread necromancy...

[woodgeek]

Re: LG Plasma 50PA5500

I'm about to dive into a repair of my LG 50PA5500. This thread helps a lot but I was wondering if there is a master service document somewhere that documents all of these steps with a flowchart or something? My symptoms are: when plugged in, the relay on my TV clicks and then the red LED on the power supply board glows. Nothing after that.

I've got a repair kit, EAY62609701, that I ordered from ShopJimmy.com, that will replace any typical failed components.