LG Plasma 42PG6010

[ocf]

Hello All,

I got this TV in recently, standby light was flashing repeatedly. Opening it up I found several caps bulging 3300uf and 1000uf on power supply and another board.

All have been replaced, TV turns on now but there is feint rainbow coloured static/noise at top of panel. It is visible only on a light background and not too pronounced.

Images below are of boards I found bad caps on, the tops of caps I replaced are marked in black.













Any idea what would be causing this rainbow static issue limited to one area of screen. Did I miss a bad cap? where is it more likely to be the main powerboard or the second board I pictured.

[ReeceyBurger123]

Re: LG Plasma 42PG6010

Better res image of the fault please ?

[vinceroger69]

Re: LG Plasma 42PG6010

can you add better pictures as reece suggests as we cant zoom in use maybe try click go advanced at the top you will see a add attachment icon (paperclip) the add your pitures that way then we should be able too zoom in on them as please remember we dont have your boards in front of us only the pictures you provide so the clearer the better thanks.

[ocf]

Re: LG Plasma 42PG6010

Link to gallery below, good res and zoomable!

http://postimg.org/gallery/2l7ml7lx8/

[vinceroger69]

Re: LG Plasma 42PG6010

can you post a image of the issue your seeing on the screen thanks

[ocf]

Re: LG Plasma 42PG6010

http://postimg.org/gallery/2y3dfb8ni/

first image is from a part of the bottom of screen, just noticed the rainbow snow showing there aswell.

Its most visible at top of screen when menu/channel selection shows, something to note when the channel selection disappears the rainbow snow stays for a few seconds in the same shape as the channel selection menu

[vinceroger69]

Re: LG Plasma 42PG6010

Maybe a firmware issue maybe reece will have a idea also as this is a plasma do all the voltages test ok? there usually a sticker on the back of the panel.

[cliff_hootarski]

Re: LG Plasma 42PG6010

Mal-discharge. Try running test patterns from the control board to rule out main board. Control board firmware can be upgraded to help alleviate the problem, however a special LG "jig" is required to do so.

[ReeceyBurger123]

Re: LG Plasma 42PG6010

Hmm thats quite severe, whats Zbais running at the Zsus ? Also whats Vs and Va running at compared to the panel sticker ?

[ocf]

Re: LG Plasma 42PG6010

Checked voltages. Found what appears to be low voltage on two pins of connector from Power PCB to Mainboard. Pins are labeled M5V_ON first is showing at 3.3v and second at 0v.

Also

Two pins on input header on Ysus board are labled 9.5v and 10.5v these are both showing at 5v this header connects back to main power PCB with pins labeled M5V.

[ReeceyBurger123]

Re: LG Plasma 42PG6010

Thats normal 3.3v is the power on signal that gets dragged to 0 with the set on. The fault will be with the higher voltages please check them.

[ocf]

Re: LG Plasma 42PG6010

I will check the VS, VA and zbias and report back.

How do I run test patterns, Read a guide but this control board seems different no jumpers

[ocf]

Re: LG Plasma 42PG6010

64.3 - VA
19.21 - VS

I found ZBAIS pin, it's on the 50 pin ribbon cable going from PDP to control board, pins are tiny, need to find my smaller multimeter probes first!

[cliff_hootarski]

Re: LG Plasma 42PG6010

You did not include any pictures of your control board, if you did I missed them.
On your board you'll see two holes labeled ext_auto_gen. Jumper/short them together and unplug the LVDS cable between the main board and control board. Turn on TV and it should display the test patterns.

Is any of these control boards yours?

http://www.shopjimmy.com/lg-ebr39594...ctrl-board.htm

Or

http://www.shopjimmy.com/lg-ebr39594...ctrl-board.htm

Or

http://www.shopjimmy.com/lg-ebr50219...ctrl-board.htm

[ReeceyBurger123]

Re: LG Plasma 42PG6010

Vs 19v ? Set your meter to Dc 600v to test Vs ! Also Zbias will have a test point on the Zsus.

[cliff_hootarski]

Re: LG Plasma 42PG6010

Vs of 19v, wouldn't charge the screen ie. no picture.

[ocf]

Re: LG Plasma 42PG6010

Jumpered the two holes labeled ext_auto_gen. Unplugged LVDS and turned TV on.

Panel lights up, I saw what looked like a shadow/burn in of a BBC news banner at bottom of screen then panel goes black, still lit with feint coloured static.

I used very fine gauge (0.1mm) copper insulated wire to jumper the holes, is this sufficient? or should it be bigger Gauge.

[ocf]

Re: LG Plasma 42PG6010

Vs - 192v

[ocf]

Re: LG Plasma 42PG6010

Copper jumper wasn't sufficient, I rejumpered. Test patterns are showing, rainbow noise/static still showing on some test patterns.

What does this prove/disprove?

[ocf]

Re: LG Plasma 42PG6010

The rainbow noise only seems to show on plain black backgrounds. RGB and other test patterns don't show it.