LG Plasma 42PG6010

[ocf]

Re: LG Plasma 42PG6010

I got a fluke 101 in the post today.

I've retested the IGBT's from the Ysus board with the fluke and I am still not seeing anything from drain to source after applying +V probe on the gate.

WTH am I doing wrong?

[ocf]

Re: LG Plasma 42PG6010

bump

[ocf]

Re: LG Plasma 42PG6010

Zsus board replacement made no change to the rainbow static.

Still seeing 1.9v on Zbias trace

[vinceroger69]

Re: LG Plasma 42PG6010

so to confirm you have repalced ysus and zsus and still have the same issue? anything else you have swopped

[ocf]

Re: LG Plasma 42PG6010

yes Ysus and Zsus replaced, issue remains.

TV is running test patterns and still showing rainbow snow on black areas of screen.

No other boards replaced

[vinceroger69]

Re: LG Plasma 42PG6010

could the mainboard firmware cause this? but why the low voltage too? what board provides that low zbias voltage?

[ocf]

Re: LG Plasma 42PG6010

I think I have schematics for this TV, I will take a look at the Zbias traces and see if I can find their source.

[ocf]

Re: LG Plasma 42PG6010

Searched through the schema, there is not even a single reference to Zbias.

There is PBias and RBias no ZBias

[vinceroger69]

Re: LG Plasma 42PG6010

so how do we know what the correct zbias voltage is? it must say somewhere i guess have you got a picture of your panel sticker with the voltages printed on it

[ocf]

Re: LG Plasma 42PG6010

https://www.badcaps.net/forum/attach...1&d=1472827971

Surely if the word Zbias is printed on the board it should be in the schematic PDF as a matter of course, searching the PDF with CTRL+F gave me no results for ZBias or variations thereoff. A search for Bias gave me the two I specified in my last post.

I remember deciphering the sticker a while ago, someone on this forum done a breakdown of the numbers and what they meant. The Zbias I believe was the final "100" value on the sticker.

Edit -

I rotated that damn image using windows image viewer before uploading but it didn't stick. Sorry for the crick in your neck guys!

[vinceroger69]

Re: LG Plasma 42PG6010

yes should be 100v so unless your measuring the wrong points im not sure where the voltage comes from maybe AlastairE may have a idea what you can check now if reece has ran out of ideas as i know AlastairE has worked on a few lg plasmas in the past

zbias is sometimes measured across a resistor and has printing on the board etc.

[vinceroger69]

Re: LG Plasma 42PG6010

not a exact match but this lg training manual may help with the zbias issue page 74 onwards it does look like the z sus board makes the voltage with your low reading

[ocf]

Re: LG Plasma 42PG6010

not a exact match but this lg training manual may help with the zbias issue page 74 onwards it does look like the z sus board makes the voltage with your low reading

That is absolute gold Vince, thank you. Where did you get this? The parent URL doesn't load anything, did you upload this?

Would love to get similar manuals for other models TV's.

Definitely looks like the Zbias is meant to be measured across a resistor. I need to take another look at the boards.

Thanks again matey, I will report back what I find!

[vinceroger69]

Re: LG Plasma 42PG6010

Found it through google search as im learning myself when i have spare time i tend too read stuff like this
The link opens the pdf for me not sure why its dosent load anything ?


Edit on page 81 you will see a chart where if you test zbias on the connector it reads 1.9 volts like what your seeing now

[ocf]

Re: LG Plasma 42PG6010

Thanks, I wasn't clear, the PDF loads but I was trying to see the website that was hosting it e.g. home.exetel.com.au, got nothing from that URL.

Sometimes I read old posts I made and think WHY THE F did I phrase a statement like that.

[vinceroger69]

Re: LG Plasma 42PG6010

Sorry i should of realised too when you said The parent URL doesn't load anything its been one of those days today, anyway i hope you manage to find the proper test points on your s sus then atleast we can go from there with fault finding etc

its a pity we cant find a training manual for your exact set as yours is a lot diffrent in regards to the s sus etc ive just looked online at your exact s sus and i cant see any test points on it.

[vinceroger69]

Re: LG Plasma 42PG6010

is there any printing on the ysus that says vzb ? maybe under the large green resistors there printing under some i cant read in the pictures.

[Alastair E]

Re: LG Plasma 42PG6010

IF VZ-Bias WAS in fact less than 5V, The picture would be completely unwatchable, Just a total mass of coloured crap on screen!

You are chasing a fault--that doesn't exist--looks like you're measuring Wrong. It Really MUST be close to, or correct voltage

You say--Its ONLY the top/bottom of pic with coloured rain on Black Scenes, the rest is OK--

This is Classic L.G. Mal-Discharge and Not Curable unless you have the F/W and the jig to download the F/W to the Control-Board.

I have the jig and the software to run it, but Not the files for that set, (I have many dozens of files as LG always had issues with M.D.)

LG Will NOT supply to anyone,--only so-called Appointed Stealers so we are all stuffed when these panels go over about 12-15K hours....

[ocf]

Re: LG Plasma 42PG6010

There are schematics around for DIY jigs, they don't look tricky to build, any chance the Mal-Discharge firmware could be found online?

Can preflashed boards be found?

[ocf]

Re: LG Plasma 42PG6010

IF VZ-Bias WAS in fact less than 5V, The picture would be completely unwatchable, Just a total mass of coloured crap on screen!

You are chasing a fault--that doesn't exist--looks like you're measuring Wrong. It Really MUST be close to, or correct voltage

You say--Its ONLY the top/bottom of pic with coloured rain on Black Scenes, the rest is OK--

This is Classic L.G. Mal-Discharge and Not Curable unless you have the F/W and the jig to download the F/W to the Control-Board.

I have the jig and the software to run it, but Not the files for that set, (I have many dozens of files as LG always had issues with M.D.)

LG Will NOT supply to anyone,--only so-called Appointed Stealers so we are all stuffed when these panels go over about 12-15K hours....

Thanks for the info mate, not great news but at least there is an answer. I might pop over to Swansea, you could upgrade the firmware for me.