LG 42PC1DA distorted pinkish when turned on

[zango123]

I have an LG 42PC1DA and when I turn on the the in the morning (when the tv is cold), the image is distorted and pinkish purple, then in clears up after about 5 minutes and the image is near perfect.

This is very much like the image TOM66 shows on his guide for this problem :"The picture is slow to update (motion blur) and has a purple or lilac tinge to it."

I dont own voltage testing equipment. Do you think it is a good idea to just change all the fuses on the zsus board?

Please help.

[tom66]

Re: LG 42PC1DA distorted pinkish when turned on

Possible a capacitor issue. Difficult to rule out without checking voltages. You can try heating up parts to see if you can make the problem go away quicker than normal.

[zango123]

Re: LG 42PC1DA distorted pinkish when turned on

I'm a novice when it come to electronics repair.

A capacitor on what components

But, can I just take off the back of the tv and apply heat with a hair dryer to the components to see if the image will clear up faster?

[tom66]

Re: LG 42PC1DA distorted pinkish when turned on

But, can I just take off the back of the tv and apply heat with a hair dryer to the components to see if the image will clear up faster?

Yes.

[zango123]

Re: LG 42PC1DA distorted pinkish when turned on

ok, I will try heating. When I open it up is there anything I should look for initially, like bulging capacitors?

[tom66]

Re: LG 42PC1DA distorted pinkish when turned on

Worth a shot.

[zango123]

Re: LG 42PC1DA distorted pinkish when turned on

Finally was able to get back to looking at the tv.

I opened up the back of the tv. Did not notice any caps that looks bulged.
(a LOT of dust though)

When I turned on the tv it looked crystal clear they I heard some slight pitch changes coming out to the power supply, and the image become distorted and pink/purple hue.

I applied heat using a blowdryer to all components one by one, no effect.

I have made a video of the tv when it is distorted: http://youtu.be/32y5i0lhZdw

What are the next steps in this diagnostic???

[tom66]

Re: LG 42PC1DA distorted pinkish when turned on

You will need a multimeter, one can be purchased for under 10 dollars in good hardware shops. It must be a digital multimeter capable of measuring up to 300V DC. Unless you want to shotgun it. I'd say the Z-sus IPM has failed. The IPM is replaceable but requires expensive tools. You can order a new Z-sus or send your old one off for refurbishment. I cannot be sure though, as you cannot test anything without a multimeter.

The Z-sus is the large circuit board in the right of the picture above with the two orange ribbons coming out of it.

[zango123]

Re: LG 42PC1DA distorted pinkish when turned on

ok. I will buy it today. Once I get it, what should I look at?

[tom66]

Re: LG 42PC1DA distorted pinkish when turned on

A closer picture of the Z-sus should reveal a place marked Vzbias. The voltage across here is to be measured and compared to the plasma panel specification, printed on a label marked PDP42X..... in the top corner of the plasma screen.

[zango123]

Re: LG 42PC1DA distorted pinkish when turned on

OK here is where I hope you bear with me.
I have never used a multimeter.
I purchased one today.

I have taken pics of the z-sus board.
I have identified where it says Vzbias. it is towards the bottom of the board on the first picture.

I will try and take a clearer picture tomorrow.

Can you explain how I would test?

[tom66]

Re: LG 42PC1DA distorted pinkish when turned on

Can we see a picture of your multimeter?

[zango123]

Re: LG 42PC1DA distorted pinkish when turned on

this is the multimeter i have.

[tom66]

Re: LG 42PC1DA distorted pinkish when turned on

Good multimeter.
You see the scale running on the left side of the dial, with "=" next to 2, 20, 200 etc? This is the DC V scale.
Set it to 600 DC V.

Place the black probe into the COM socket. You should not need to change that.
Place the red probe into the V ohm mA socket (ohm represented by horseshoe.)

Find the points on the Z-SUSTAIN mentioned previously marked Vzb. If you need me to highlight these, post a clear picture of the Z-sustain.

Vzb should be around 90 to 120V on these, exact voltage written on the panel sticker marked PDP42X#####.

e.g.
Vs: 185V Va: 65V
N/A / -170 / 190 / N/A / 115

[zango123]

Re: LG 42PC1DA distorted pinkish when turned on

Here are some clear pics of the z-sus board and the panel sticker.

[tom66]

Re: LG 42PC1DA distorted pinkish when turned on

Here. Red probe goes on the metal contact of the highlighted device, black probe goes on the screw.

[zango123]

Re: LG 42PC1DA distorted pinkish when turned on

ok so the red probe should touch the black square and the black probe should touch the screw... ok. But, is this with the tv turned on? (novice remember )

[tom66]

Re: LG 42PC1DA distorted pinkish when turned on

Red to touch the bottom metal portion of the black device below the label "Q18" (this device is called "Q18" for future reference.)

[zango123]

Re: LG 42PC1DA distorted pinkish when turned on

tv connected to power outlet when I do this?

[tom66]

Re: LG 42PC1DA distorted pinkish when turned on

Yes, screen lit up with fault symptom visible.
Be careful not to slip with the probes!