LG 50PS60 UA Plasma

[Izzy_Reak]

I have an LG 50PS60 UA Plasma, manufactured 11/2009. I turned it on this past Thursday, and as it powered up, it played video and audio from my cable receiver, but after about two minutes of play, the display went black, and when it came back up, the screen had blue/green/speckles all over it.

I powered it off, turned on the Blu Ray player, and the display was still the same. I unplugged the power for two hours, and when I plugged it back in, sans blu ray player, the display booted up with the Blu Ray screen, still jumbled of course, but as previously mentioned, no blu ray was connected to the LG.

I hope to inspect it further, but honestly, I'm not sure where to start. I've scoured the internet to no avail. I've added a quick video to YouTube to show the display I'm seeing.

https://www.youtube.com/watch?v=3vZk3ZvofMc

If anyone has an idea, I would be very grateful.

Thank You,

Izzy

[Alastair E]

Re: LG 50PS60 UA Plasma

Looks like summit amiss with the Y-SUS and the Buffer-boards depending on what Chassis that set uses.

Remove the back and take pictures of all the boards inside, post here....

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I will, Alastair! You are so kind, and very quick on the draw!

Thank You So So MUCH!!!

izzy

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

Alastair,

Thank you again for taking the time to assist me with my TV.

Izzy

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

And one more.

izzy

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I just checked the AC IN Connector (AC INPUT FILTER) that attaches to the Power Supply (SMPS) PWB board, and the red wire is reading 122 VAC, and the blue wire is reading 1.6 VAC, the label on the AC IN Connector says it should output approx. 240VAC.

I hope I'm helping!

[tom66]

Re: LG 50PS60 UA Plasma

We know the TV is receiving AC power or it would not work at all. So for now no need to test the AC filter.

Let's focus on the large left-hand board right now. It's the Y-sustain (Y-sus) board and it's connected to a pair of Y-buffer boards, the Y-buffer top and Y-buffer bottom.
https://www.badcaps.net/forum/attach...7&d=1426972439
Try and get a clearer photo of the Y-sustain - we need to be able to see some of the finer detail on it if possible.

At the top of the chassis there's a sticker listing a variety of voltages, and the panel model number. It'll be marked something like "LG Electronics PDP60H9###### Made in Mexico"... I *suspect* your set has a 50H3 panel, but I'm not sure, as I last worked on one of these over 3 months ago.

Can you get a clear picture of this sticker?

Layout info.

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I'm on it, Mr. Tom!

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

You're going to yell at me because my camera has been found wanting in performance. BUT I did the next best thing. I took the pictures you requested, then wrote down all the data for you.

Thank you so much for having this information available.

The information on the chassis label is:
Model: PDP50H30022
910K35OH3006207.AKLGGDC
Voltage Setting: 5V/Va: 60/ Vs:195
N.A. - 180/150/N.A. 105
Korea 2009.10
Total Max Watt: 500W
Max Volt: 5.25V/68Va/198Vs
Max Amps: 7.5A/2.5A/2.5A
There's a part number stick on the Chassis that's separate:
AFT72909801
K5009A007455

The YSUS board has this sticker:
E8R818300001
YSUS
KP5009AJ007018
2009.10.07

[Alastair E]

Re: LG 50PS60 UA Plasma

No--They are OK for now.

We need to check the various voltages the set runs on. Voltages such as Vs, Va, -Vy VSC and VZ-Bias etc....
--These are the main voltages the panel itself needs to run correctly, I'm just guessing one is absent or very wrong, as you have a condition of severe 'Mal-Discharge'....

The Vs, Va are on the PSU, the VSC, and -Vy is on the Y-SUS and VZ-Bias will be on the Z-SUS....

[tom66]

Re: LG 50PS60 UA Plasma

Ok, see this document:


See page 121 check Vs/Va (do not adjust Vs/Va yet)

See page 123 check -Vy/Vsc (again do not adjust yet)

See page 128 check Vzbias (again do not adjust yet)

For all voltage checks, leave all connections installed. Set must be powered on.

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I'm gonna do that IMMEDIATELY!

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

Vs Pin 1 and 2 read 5V
Va 6 and 7 read 0
also, when I turned it on tonight, there was a pop, and now there's no picture.

I don't feel like I'm lending enough help to my own cause. I put my DMM on 2K Ohms and read R305 and R306
-Vy R305 4.4
VSC R306 -1.2

And 99 Volts for Zbias

I apologize for my lack of knowledge, but I do appreciate all your help.

Thank You,

Izzy

[tom66]

Re: LG 50PS60 UA Plasma

You need to use the highest DC volt range for your meter rather than kohm. Was set powered up? Vs and Va should measure around 190V and 60V each respectively, so I would double check your measurements. Vs/Va that low will not allow for anything to appear on the screen... not even a faint image...

Note, to measure voltages at pins of connectors, you can put the red probe on the connector pin (with the connector still installed) and black probe on the chassis of the TV, like the internal wall mount bracket. The back of the plasma screen is grounded.

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

Thank you for patience, Tom. I'll double check those this afternoon.

izzy

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

Good Afternoon, from Virginia-

Thanks you, Tom, and Alastair for your continued patience, I finally have the readings you asked for.

One note of change: On Sunday evening, I powered up my television to a "popping" noise, and my television no long has a display on the screen. It still turns on, however.

I was still able to find the correct voltages:
Vs on pin 1 and 2 show 194 volts
Va on pin 6 and 7 show 58.7 volts

HOWEVER, -Vy shows 14.5 volts, and after three seconds, drops to -4, the back up to 14.5 volts in a quick increment. I can hear it buzz when the voltages change.
VSC reads 16.4 volts, drops to 7.4 and sometimes 8.8 volts every three seconds or so. I can hear the same buzz with the probe from my mm on the board, or off.

VzBias is reading 104.5 volts.

I apologize for my delay in response. I had a long work/school day yesterday (5am-1030pm!)

-izzy

[tom66]

Re: LG 50PS60 UA Plasma

Ok, I am suspecting bad Y-buffer boards. I've highlighted these boards - they'll probably be marked YDRVTP and YDRVBT or something like that.

For this test, you should disconnect the buffer boards from the Y-sustain board. To do this, you'll first have to unscrew the boards and disconnect the link cable between the two boards, and the top board and Y-sustain. Then, gradually slide the boards left until they loosen.

Leave the orange ribbons attached and connected to the board - they are not important for now. The ribbons are difficult to line up again so removing them should be avoided unless necessary. Simply fold each board over the chassis, being careful not to flex the ribbons too much, and tape them down to hold them out of place. The end result is the buffers should be connected to the plasma display panel itself via the orange ribbons but disconnected from everything else.

Then power the set up. I'm not expecting anything on the screen but I'd like you to check -Vy and Vsc again. If the voltages measure close to what they should and if they are stable, start by reconnecting the TOP board. You'll have to connect the little ribbon cable between the top buffer and Y-sustain board. At this point you -may- get an image on the screen (it depends.) Please check -Vy and Vsc in this condition too.

• If the voltages do not come back with the buffers disconnected your Y-sustain is bad.
  
• If the voltages do come back with only the top connected your bottom buffer is bad.
  
• If the voltages do come back with the buffers disconnected but go away when they are connected (which you tested previously), your top and possibly bottom buffer boards are bad.

Don't connect the bottom board yet as it cannot be connected without the top being connected.

The boards are pretty cheap (about $40 for the pair), so it's probably worth ordering both to fix this fault if they are determined to be faulty.

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

Good Evening/Afternoon!

I disconnected the Y-Buffer boards from the Y-Sustain board. The surging did stop.

-Vy=-88.5
and VSC=61.2 Volts. Both, I assume, are way out of range.

I found that the Y-Sus board, the part number is actually EBR6183001 is no longer in production, and hard to find, even used. I'm not sure if used is recommended. I did happen to find on a TV Repair parts website, that the replacement board is EBR6183002, and costs approx. $150.00.

Do you think the surging means the Y-Buffer boards are bad as well? And is this television worth saving?

izzy

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I went back, and plugged the top Buffer board into the Y-SUS, and that's when the Y-Sus surges at -Vy and Vsc, and gives me the crazy 16 V readings.

I thought I would add that in the post.

[tom66]

Re: LG 50PS60 UA Plasma

Are you measuring -Vy/Vsc across those resistors directly? i.e. red probe one end black the other?