Re: LG 42PC1R Bad picture

I have downlaoaded service manual, but there is not mentioned where testpoints are. Only for va and vs testpoints. I have cheap noname dmm . I try another one tomorow.

Re: LG 42PC1R Bad picture

I found fault on z-sus board. On z-bias voltage control board i was replaced kia431a, and then on z-bias testpoints shows 75V. Then i turn potentiometer and its goes to 100V.

Now i found one new symptom, when i tried to raise vs to normal voltage then Z-bias testpoints shows random voltage. Like vsc and -vy

Z-bias , -vy and vsc voltage control boards is all same type. Can you explane me how i can measure z-bias, but i cant measure -vy and vsc?
I now tried to measure them directly pins on voltage control boards, but...

Re: LG 42PC1R Bad picture

How i find that ipm model nr or replacement part model nr?

Re: LG 42PC1R Bad picture

All fuses are not blown, there is some little smd fuses, but they was ok.

I tried to measure z-bias, -vy and vscan, but no result. If you say these are floating ground then i need different voltmeter?

Here is one more symptom ; when i turn z-bias potentiometer, then no changes on screen.
Imeasured between ground and z-bias + testpoint and reading is same as va 60V.

Re: LG 42PC1R Bad picture

I tried to measure several times z-bias voltage on z-sus board, but every time i get same voltage as va 60V. Replaceing whole board is impossible, because its very rare tv set in here.

Can anybody tell how to test that Ipm module to be sure that is faulty?

Hello!

Does anybody know where is this tv -vy, vsc z-bias and other testpoints? I was tried to measure these but on d.m.m. screen shows random voltage. I think maybe i was measured wrong points?
On sticker va is 186v, when i turn potentiometer and set voltage minimum 177v before tv shuts down , then picture goes to normal. But onlu when on screen is darger image, when comes lighter then white areas is starting flicker.

If i set va to normal 186v, then all colors is messed and red tod and stripes and flickering is showing.

Sorry for bad language=D

Re: New Members - please post your introductions here

Hello!

I want try to repair my tv and need to start new thread to ask where are voltage measuringpoints =)