L.G. 42PC1D, dark flickering pic.

[Alastair E]

Have this L.G. with the above fault. Maybe unrelated, but also has some red sparkles,--but only on black/very dark parts of the picture.

When first on, it has a reasonable pic--apart from the sparkles on black, but then after about 15 mins will mess around, going from a fair pic to dark, flickering brighter Guessing the sparkles need the software update thats mentioned in other threads....

At work, I'm pretty sure I have some software and cables to do this update, will have to check--defo something for LG sets, a CD and a serial-cable I think.....

Also--when the pic goes dark--the colours go psychodelic--like a cartoon interpretation of a 60's acid-trip!

Checked the voltages--seem good, all are within a volt or so.

Any ideas....?

[tom66]

Re: L.G. 42PC1D, dark flickering pic.

Check Vs, Va, -Vy, Vsc and Vzbias before and after fault.
Panel model PDP42X3?

[Alastair E]

Re: L.G. 42PC1D, dark flickering pic.

Hi Tom!--How you doing?

Yes,--Its a PDP 42X3 panel. --What is known about these, anything common faultish?

Checks earlier were rather quick, as not all the test-points are obvious--or at least I didnt see them!

Va, Vs and I think -Vy were good though....

[tom66]

Re: L.G. 42PC1D, dark flickering pic.

See here for volt checks:


Common faults -- usually the damn IPMs!

[Alastair E]

Re: L.G. 42PC1D, dark flickering pic.

Ah--Cheers!

As to IPM's, I noticed the Z-sus IPM is nearly stone cold, while the Y-sus IPM is warm, but not hot...

Thanks, I'll check the voltages in working and fault conditions,--but will have to wait till tomorrow eve....

[Alastair E]

Re: L.G. 42PC1D, dark flickering pic.

Here are the results of the voltage-checks....

Vs, 186v constant and correct to label.

Va 60v constant and correct to label.

-Vy 130-160 varying, re-set to close to 200, but varies between 190 and 210v
--Label says 200 for this value. Difficult with DVM to read exactly the variance--but its around those values.

Vsc, should be 120, but varying between110 and 120 ish--difficult to see, should break out my Avo-8 analogue meter!

Vbias was correct at 200 to label and constant no variance.

Z-Sus IPM still stone-cold, and Y-sus IPM tepid/warm. I did pull the Vs fuse on the Z-sus to see the effect.
--I had a dark but constant slow to refresh picture--that didnt flicker, but with poor colour...

Is this looking like an IPM or is one of the DC-DC converters of the Y-sus messing round...?



Ive not done any firmware updating--tracking down a windows XP machine!

[tom66]

Re: L.G. 42PC1D, dark flickering pic.

You checked Vsc and Vzbias too?

[Alastair E]

Re: L.G. 42PC1D, dark flickering pic.

Sorry--Yes, You were too fast for me, I just edited when I noticed I missed them out...

Vsc varying somewhat and Vzbias correct and constant

[tom66]

Re: L.G. 42PC1D, dark flickering pic.

I would consider the possibility that you have two faults. Can you post a picture of the Z-sustain board?

[Alastair E]

Re: L.G. 42PC1D, dark flickering pic.

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and y-sus--poor pic, all the frame is in the way...

[tom66]

Re: L.G. 42PC1D, dark flickering pic.

OK, bottom left of Z-sus. Check voltage across one of those red caps. Should be around 60 to 150V. Also should match voltage on similar bank of red caps on Y-sus.

Sure about 200V Vzbias?
Vzbias, as a rule, always less than Vs and also, is usually around 80V to 130V.

[Alastair E]

Re: L.G. 42PC1D, dark flickering pic.

Ah--Yes, sorry, been battling with various Vestels this afternoon--Head's gone!

That Vzbias is 100V dead and constant--correct to label.

The voltage across the red-caps of Z-sus is 140-158 varying....

The voltage on the 5 red caps of Y-sus is 95 constant.

[tom66]

Re: L.G. 42PC1D, dark flickering pic.

You have a bad IPM on the Z-sustain, I think. You can verify this theory if you have an oscilloscope, do you?

[Alastair E]

Re: L.G. 42PC1D, dark flickering pic.

Yup--I have a scope, but will have to wait till tomorrow eve--Need to wind down--gotta get up for work at 6am!

What should I be checking for--guess that ramp waveform on its output...?

Do you still reckon I may have two faults--or was that because I messed up with the voltage-readings in previous posting?
A big thank you for taking the trouble to help--If you need any Vestel stuff, I have loads, you are welcome....

[tom66]

Re: L.G. 42PC1D, dark flickering pic.

The Z-sus waveform is simpler, no ramps. Just a Vzbias point and a sustain portion.
What Vestel bits have you got?

[Alastair E]

Re: L.G. 42PC1D, dark flickering pic.

PSU's, Mains, TFT's (some) T-Cons, BL boards--you name it, various series from 17MB12 to 17MB90....

Prolly got 30-40 mains and PSU's.....
--Been a good (bad) week, scrapped around 6 Vestels today with cracked TFT....

[tom66]

Re: L.G. 42PC1D, dark flickering pic.

I will keep you in mind. I repair vestels now and then if I get them cheap, but I hate them with an absolute passion.

[vinceroger69]

Re: L.G. 42PC1D, dark flickering pic.

PSU's, Mains, TFT's (some) T-Cons, BL boards--you name it, various series from 17MB12 to 17MB90....

Prolly got 30-40 mains and PSU's.....
--Been a good (bad) week, scrapped around 6 Vestels today with cracked TFT....

hi alastair i have 2 sets here both have vestels mains can i send you the board numbers to see if you them them as i strugling to find them.


will pm you the main board details save messing up the thread cheers

[Alastair E]

Re: L.G. 42PC1D, dark flickering pic.

I will keep you in mind. I repair vestels now and then if I get them cheap, but I hate them with an absolute passion.

You and me too! I picked up a JVC today off the pile, and thought--Ah, a nice straightforward Japanese type PSU needing 3300uF caps....
(I work at the local recycling-centre--Fixing tellys for re-sale!)

Was it hell--A bloody Vestel in disguise--Havent seen one wear a JVC badge before though....

I have a 3 foot pile of those hideous 22" Technikas with the DVD that never works that Tescos sell, one Saturday a while back--I secretly took one and jumped on it till it was merely bits!--Most satisfying!

Vinceroger--OK, I'll have a look through--What you got?

[tom66]

Re: L.G. 42PC1D, dark flickering pic.

JVC, Sanyo, Hitachi, Sharp and Toshiba below 42" and not Smart: They are ALL VESTEL SHIT...

It pisses me off SO MUCH.

And you see people review a Toshiba 32" LCD giving it great reviews, great performance, etc. When they review the equivalent Celcus, Technika, etc. it gets poor reviews. Brand blindness is what I'd call it.