LG 60PC1D-UE picture messed up

[shelby5041]

Re: LG 60PC1D-UE picture messed up

the only way i can get vsc and vsetup voltages on y board to read good is if logic board to y board is disconnected

[shelby5041]

Re: LG 60PC1D-UE picture messed up

update...im stumped

replaced y board ...no change in symptoms and no change in voltage readings
replaced logic board no change in symptoms and no change in voltage readings

vsc and vsetup still no good

all other voltages test good

not sure what to do now?

[shelby5041]

Re: LG 60PC1D-UE picture messed up

hey doc.....r u saying that ur issue ended up being a bad logic board......?

[shelby5041]

Re: LG 60PC1D-UE picture messed up

faulty board i agree....but with exact same symptom?

ill let u know....

you originally said you thought it was a logic issue.....we will c

[Doc38343]

Re: LG 60PC1D-UE picture messed up

You can't apply this logic (pun not intended), as the boards are too interrelated. The logic/control board sends multiple signals that control transistors on the sustain boards, if those signals are bad it could cause your fault. And it is more than possible that you have received a faulty Y... Happens plenty of times.

The one thing I'm fairly sure it's not is a bad panel, this kind of failure basically doesn't happen with a plasma.

Hey guys I just went thru a similar hell on that Samsung plasma... sounds very similar situation although i know it is a totally different set...
Is there a way to do a test pattern test of the control board on this set??
On that samsung it had 4 test points marked 1,2,3,4 and i had to jumper a couple together, then with the A main disconnected from the control board, plug it in... I did not get the expected test pattern and it turned out to be a $14 control board....
On that model the usual failure was the y-sustain $139 then they replaced the upper and lower y-buffers another $40 and they had replaced the power supply before i got it in here.... started the thread a year ago... LOL
Could have done that test pattern test any time....Do not know if this model has such a test.

[tom66]

Re: LG 60PC1D-UE picture messed up

well to me i would think if i disconnect logic board and i get good voltages.....then logic board is bad?

i cant imaging having 2 bad ys with same issue so i have to assume y is good since i get good voltages on both boards when disconnect logic

You can't apply this logic (pun not intended), as the boards are too interrelated. The logic/control board sends multiple signals that control transistors on the sustain boards, if those signals are bad it could cause your fault. And it is more than possible that you have received a faulty Y... Happens plenty of times.

The one thing I'm fairly sure it's not is a bad panel, this kind of failure basically doesn't happen with a plasma.

[shelby5041]

Re: LG 60PC1D-UE picture messed up

unless its a bad panel...and when logic is disconnected its not doing same work and with logic it does more work and hence making vsc and vsetup messed up

..anyways logic board is only $20 so its worth a try

[shelby5041]

Re: LG 60PC1D-UE picture messed up

well to me i would think if i disconnect logic board and i get good voltages.....then logic board is bad?

i cant imaging having 2 bad ys with same issue so i have to assume y is good since i get good voltages on both boards when disconnect logic

[tom66]

Re: LG 60PC1D-UE picture messed up

im thinking not y issue only because i replaced y and tv had same symptoms

odds of 2...ys with same exact symptoms rare

u originally said does.it seem y or z issue

so this may indeed be logic issue?

I really couldn't say for sure.

[shelby5041]

Re: LG 60PC1D-UE picture messed up

correction...doesnt seem....i hate touchscreens lol

[shelby5041]

Re: LG 60PC1D-UE picture messed up

im thinking not y issue only because i replaced y and tv had same symptoms

odds of 2...ys with same exact symptoms rare

u originally said does.it seem y or z issue

so this may indeed be logic issue?

[tom66]

Re: LG 60PC1D-UE picture messed up

Sounds like an issue with control board signals OR a hardware fault on the Y-sustain causing a short on Vsc - not easy to tell without using a scope and a lot of debugging.

[shelby5041]

Re: LG 60PC1D-UE picture messed up

tom
when i disconnect buffers from y....bad vsc vsetup

if i disconnect logic board from y.with buffers connected to y.....i get good vsc and vsetup



vsc 110.6v
vsetup 249v

what can this mean?

[tom66]

Re: LG 60PC1D-UE picture messed up

Could be a Y-sustain issue or a control board issue...hard to tell.
If you have a scope or access to one that may be useful.
You can try with the buffers disconnected.

[shelby5041]

Re: LG 60PC1D-UE picture messed up

should i try to test vsc and vsetup with other boards disconnected to try to isolate?

[shelby5041]

Re: LG 60PC1D-UE picture messed up

vsc and vsetup tested per serv man using test points across resistors


what di the bad readings at vsc and vsetup mean?

[tom66]

Re: LG 60PC1D-UE picture messed up

Make sure you're using the right ground as specified in the manual, Vsc and Vsetup are not always tested wrt to chassis ground.

[shelby5041]

Re: LG 60PC1D-UE picture messed up

if vsc and vsetup voltages are messed up doesnt that mean y or y buffer issue?

[shelby5041]

Re: LG 60PC1D-UE picture messed up

Also

Zbias 170v actual.....specs 170v

Ydrive waveform ....2v.actual...waveform did not resemble specs at all.....specs 220v

[shelby5041]

Re: LG 60PC1D-UE picture messed up

Hi tom here are voltages using test points per serving manual....

Panel specs

Va 60v
Vs 193v
Vsc 110v
Vy -65v
vsetup 250v

Actual readings

Va 61.3
Vs. 194.8
Vy 64.6
Vsc fluctuating and out of range above 600v
Vsetup no reading/out of range above 600v