LG 60PA6500 - Pixelated garbage vertical lines only

[Mr.Stowell]

A couple weeks ago my son comes and says "Dad, the TV shut off". Well I go turn it on, no picture. Fine. He's supposed to be doing schools stuff so I'll get to it eventually. Fast forward a couple weeks. I've checked power supply voltages (all match up with sticker), pulled boards and cables to visually verify no burnt spots or bad solder joints, had a friend come check MosFETs (mostly good but not sure there isn't one weird one on the YSUS board), etc. Can't track it down.

Current state: Putting TV in test mode (jumping pins on controller EXT_AUTO_GEN) will display the pixelated vertical bars (no real picture) but I do see a full white when it hits that part of the test. I also see the moving horizontal bars during that part of the test. Just turning on TV is like the inverse of the test pattern. Just a few narrow vertical lines of pixels and the rest black space.

Hoping someone will take a look at the picture of my screen (supposedly displaying the test pattern and be able to tell me if it's toast or if there's hope. I'm not in a big rush to fix it. My kids can live w/out a TV for a while !

Looks like most of my pics got rotated 90 degrees. Sorry about that.
Thanks,
Randy

[Biruslapio]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Remember that to do the AUTO_GEN test properly, the LVDS cable from main board needs to be unplugged, if it still has these vertical lines in a pattern all over the screen the logic board would be to blame, and without LVDS and no AUTO_GEN pads shorted, the tv should come on with a black screen only.

[tvtimmy]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

+1

[Mr.Stowell]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Yes, the Auto_Gen test was run with the LVDS cable disconnected. The screen is black with the cable disconnected and Auto_Gen not jumpered.

I noticed today when double checking with Auto_Gen jumped the set comes on for about 3-5 seconds and then shuts down. w/out the jumper it stays on with a black screen. I plugged my iPad into HDMI one and get sound and a black screen. Not even getting the vertical garbage anymore.

[Biruslapio]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Is the jumper well connected? Soldering a wire jumper between the two AUTO_GEN pads is a guaranteed method.

Looks like a bad logic board from everything up to now, you should unplug the motherboard power completely and let only Y and Z boards be plugged into the power supply to avoid it shutting the TV down.

[Mr.Stowell]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Gonna try picking up a logic board and see what happens. Thanks for the feedback.

[Biruslapio]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

I don't recommend buying the logic board before performing the tests at my previous reply #5, unless it's still defective, then a replacement is suggested.

[Mr.Stowell]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Update on TV: I did order a used logic board that arrived Monday since it was just over $16. It happened to be a rev 1.0 board and mine was a 1.1 but the part numbers matched so I figured I'd give it a shot. The TV fired up and I had a picture. Awesome! So I finished dusting off the back cover, put it back together, and hung it back up on the wall. Used it for maybe 30 minutes just checking out stuff. Tuesday I suppose my 15-year old worked it out for a couple hours of Netflix and my daughter had an assignment to suffer through the US Presidential debate and take notes. Then today my son comes and says "Dad, the TV shut off again and when I turn it on.. no picture". My response: "I guess you're supposed to do your school work then." ha ha. So eventually I'll pull it off the wall again and get it back on the stand to work on it. I've been painting the exterior of my house the past 3 days and still have a couple more days to go to finish the trim before I'll worry about the TV.

Next steps?
If it blew up the control board (EAX64290701), I suppose I should double check the voltages out of the power supply's bottom right connector?

Attached picture of new logic board that lasted 2 days.

[Davi.p]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

I don't think this Tv is 15 years old watching the circuitry type, it seems in the LED tv era.. the fault symptom tells me about a cpu soldering problem, as usual..

[SMDFlea]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

L101 is damaged .

[Biruslapio]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

L102 looks broken and L101 is missing it's other half, did the board come like this or did it explode out that inductor? Never seen anything that could cause this.

[Davi.p]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Which board you are referring to?

[tvtimmy]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Your logic control board pictured.

[Mr.Stowell]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Wow! I didn't notice those were blown. I didn't look that closely before I swapped the board. That picture was taken with the TV working before I hung it back on the wall.

For comparison, I've attached a clear picture of my original control board.

[Mr.Stowell]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Newest Update:
I picked up a different logic board that looks physically sound. While waiting for it, I tried the Auto_Gen test on that bad controller with LVDS power and ribbon cable disconnected and was able to get the TV to run the test patterns for about an hour. Watched a bit of Netflix that night and powered off. Next day tried to turn on and back to no picture. Couldn't get Auto_Gen test either. So now the latest board is here and in the TV, but I decided to check all my voltages before hooking up inputs and trying for picture.

With Y and Z boards connected, the Va (55V) power was oscillating between 0 - 55V. The Vs (205V) was bouncing between 204.4 and 205.5V. There is also a steady ticking sound coming off the PS board somewhere. That ticking is constant as long as the board has power.

With all power connectors disconnected from the power supply board I get more stable readings.
Va: 55.2 - 55.5
Vs: 204.4 - 205.5
5V: 5.22
17V: 17.15 - 17.16

Just hooking up the Y-SUS board and Va gets wonky again.
Va: 0 - ??? Meter can't display numbers it flashes so fast.
Vs: 204.2 - 205.2
5V: 4.85 - 4.87
17V: 17.14

Just the Z-SUS board plugged in and power readings are:
Va: 55.1 - 55.4
Vs: 205.3 - 204.5
5v: 5.12
17V: 17.14

I'm about ready to go shopping for a new TV unless there's a clear sign that either the Power Supply board or the Y-SUS board is the culprit.

[Biruslapio]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Unplug VA cable that goes from the Y-SUS to the X boards on the bottom of the TV, the panel should come on if everything else is working, if there's a problem with VA voltage, may be a bad panel leaking voltage to logic board or some short on the lower boards, this TV model has a frequent problem that the upper Y buffer shorts out.

[Mr.Stowell]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Thanks for the suggestion.
XSUS and YSUS power cables connected to power supply board and 2-pin VA to X boards disconnected. Still have the power disconnected to input board.

Va: 55.4 - stable
Vs: 204.6 - 205.1
5v: 4.99-5
17v: 17.14

Connect power back to X boards and Va freaks out again.

Decided to disconnect the ribbon cables feeding X boards and plug back in Va power.

Va: 54.5 - 55.5. But at least it's now in a small range.

Additional testing following the power path through the X boards:

XL + XC power and ribbon cables attached - Va is 55.3-55.4
If I plug in the XR power it's still good with all 3 powered.
Finally, if I plug in the XR ribbon cable to the controller, Va is no longer stable.

[Biruslapio]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

Does the panel light up when VA is stable? even if it's all black.

[Mr.Stowell]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

I am no longer getting the green glow of the panel when I plug in the power. I've got Y-SUS and Z-SUS, and X (power) connected.

Added the power to input board and used the remote to power on, red light flashes twice and no glow. Push power button and the PS clicks off, standby turns red. No hum from Y or Z boards like I used to hear when power was on.

[Biruslapio]

Re: LG 60PA6500 - Pixelated garbage vertical lines only

It's best now to leave mainboard out, just focus on the Y/Z/X and logic board voltages, short the AUTO_GEN pads, what voltages are the VSCAN and -VY test points on the Y-SUS?
Test Y-Buffers for short circuit on the output pins to the screen, use floating ground as the positive and negative goes onto each horizontal pins on the buffer boards, anything below kOHMs is bad.
I have a 60PM6700 here with bad buffers (same everything except for the main board), using my multimeter forward voltage is 0.750 on good pins and 0.001~0.015 on the bad ones.