LG 60PS11 (plasma) no picture

[j_rigsby]

No picture or OSD. Seems like it wants to energize, screen breifly lightens up when initially turned on. Lasts maybe 1/2 second, then total blackness.

Sound is good. Menu and input buttons work (I can change inputs and get sound from multiple devices connected, but no picture)

From what I have ascertained thus far from reading tomcat66's wonderful troubleshooting guide is that I should be checking the fuse(s) on the Y main for continuity.

I have found the block diagram in the resources provided on this site, although I am having trouble identifying where exactly the fuse(s) is/are on the Y main. I haven't pulled the back off the unit yet; I will be doing this tonight (hopefully they are obvious). Thought I would post this to gather some support for the steps that lie ahead and to also thank those who share their vast knowledge with us who are new at this.

Hopefully I can get this figured out. I am curious about getting parts for this unit once I figure out what the problem could be. I know tomcat66 mentioned something about replacing the entire Y main if it were found to be faulty as a matter of convenience over troubleshooting individual components. Where does one order the parts? Thanks for the help.

[tom66]

Re: LG 60PS11 (plasma) no picture

It's tom66

As for the problem, it sounds like possibly a main board fault, given the brief screen energisation. Do you own a digital multimeter to make some tests?

Ordering parts: shopjimmy (new from scrapped sets, tested), tristate module, LG directly (more reasonably priced than you'd expect), eBay, etc.

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Sorry Tom. Not sure where I got the cat from.

Anyway, yes I do own a multimeter. Got the back off and found one fuse right where the power bridges into the main board. It was good. Didn't find any other obvious fuses anywhere amongst any other circuitry.

What tests should I be making next? I have the block diagram handy.

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

So I did a little bit of research. Just doing some observation work as I do not wish to destroy things that are not ruined already.

Green led on logic board does not flash evenly after start up. The sequence seems fine, as in one led goes solid, other flashes about once per second. Then, flashing led (after two consecutive flashes one sec apart) does the following: long flash short flash, long flash short flash. two full seconds, then it repeats the same way.

Looks like an error message to me, yet I cannot find data anywhere on error sequencing.

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Anyone have any ideas on this? Any assistance would be much appreciated.

[tom66]

Re: LG 60PS11 (plasma) no picture

Would you be able to use a multimeter to check the Vs, Va voltages?

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Tested connector blocks P811 and P812 (x and Y)

VS = 197.7 VDC on all pins
VA = 68.5 VDC on all pins
5.12 VDC on 5V pin

[tom66]

Re: LG 60PS11 (plasma) no picture

OK, on the back of the plasma screen metal plate, there is a model printed like PDP50K1##### near the LG Electronics information. What is this model number?

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

P 813 and 814 connectors all have correct labelled voltages as well.

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Model is PDP60H30001

[tom66]

Re: LG 60PS11 (plasma) no picture

Great, I have PDP60H3 manual

(search for "60H3")

This manual indicates how and where to test Vsc and -Vy. Please check these voltages.

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

-Vy is 2.1 to 2.3 VDC
Vsc is 2.8 to 3.1 VDC

Obviously too low. This means the Y main is buggered?

[tom66]

Re: LG 60PS11 (plasma) no picture

Please see what happens to those voltages if you isolate them from the Y-sustain.

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Not sure what you mean here tom. The voltages were taken directly on the Y sustain board. How am I supposed to isolate them? Unplug the Y sustain from the power board? Or do you mean to isolate the Y-sustain from the logic board?

[newtothis]

Re: LG 60PS11 (plasma) no picture

Disconnect Y-sus from PSU and test the pins

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

I disconnected the LVDS ribbon cable and jumped pins 1&2 on the AUTO GEN and did not get a test pattern on the screen.

I also disconnected the cable from the Y-SUS to the board directly underneath (X-Drive left?) and tested -Vy and VSC. Both were less than.05 VDC. Tried testin with logic control board disconnected, same result.

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Disconnect Y-sus from PSU and test the pins

PSU = Power Supply = SMPS?

[tom66]

Re: LG 60PS11 (plasma) no picture

Uh, my error. I mean disconnect the Y-buffers from the Y-sustain. Doh. Do the voltages rise?

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

If yes, then both -Vy and VSC are 0.005 VDC after disconnecting from power supply.

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Will try that, but looks like I may have to unscrew Y-SUS from frame, no?