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Old 04-04-2015, 10:44 AM   #1
rlester
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Default LG 42PC3DVA Plasma no picture.

Friend gave me this TV. He said there was sound but no picture. I noticed if you turned on the power, the led would go from red to green for less than five seconds, then turn off and go back to red.

Removed the back cover and discovered one bad fuse on the Y sustain board. New fuse made no difference. I pulled the power connector off the Ysus board and then turned on the power. Now the power stays on with the green led for a long time. Plug the connector back in and it only stays on for a few seconds as before. Tried it several times both ways. So, I take it this board is toast?

Found an ebay link to a guy here in Alberta with a repair kit. Does this look like the right repair kit?

http://www.ebay.ca/itm/YSUS-Board-68...3a3618c&_uhb=1

I checked the voltages on the power connector for the Ysus and I'm getting 4.92 volts and 59 volts on the va wire. Is this correct?

There are no visibly blown or swollen caps anywhere on any of the boards.
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Old 04-04-2015, 11:14 AM   #2
capkid
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Default Re: LG 42PC3DVA Plasma no picture.

Yes, you most likely have the infamous blown IPM on the YSus, and that kit should correct the issue. I'd ask the seller if the IPM is new or used. A used IPM may have a short remaining lifespan.

Here's what I'd do:

(1) Disconnect the YSus from the PSU then check the VS voltage, also. VA looks fine at 59V. The specs are located on the panel label.

(2) Check the Vzb voltage on the ZSus. You may want to consider replacing the IPM on the ZSus, since it could be on its way out, but I'd personally just ride it out to failure in a TV this old.

Video on replacing an IPM: https://www.youtube.com/watch?v=Y8MNQYXw8E0. Additionally, I like to add a little fresh solder to each of the IPM pins to help the melting solder flow better.

Last edited by capkid; 04-04-2015 at 11:23 AM..
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Old 04-04-2015, 02:21 PM   #3
rlester
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Default Re: LG 42PC3DVA Plasma no picture.

Thanks capkid! I will definitely check the Vzb voltage and see what that is. Like you said, if that checks out fine, I will just leave the ZSus for now.

I did contact the seller and asked if the IPM is new or used, the response was this:

"It's manufacturer refurbished and fully tested."

So, to me that means it's used. If it works, that doesn't bother me, but as you mentioned the lifespan may be shorter.

That being said, it is heat that causes these to fail from what I understand. So, has anyone considered installing a fan on the heatsink to cool it better? Maybe one from a video card or something like that. Then there is the question of do you just tap into a 12 volt source somewhere on the main power supply?

I'm willing to install fans for both the YSus and ZSus if necessary.

That video was good to see, I might invest in a solder sucker.
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Old 04-04-2015, 06:09 PM   #4
capkid
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Default Re: LG 42PC3DVA Plasma no picture.

I trust this seller (Coppell TV Repair): http://www.ebay.com/itm/160516239386

I, like others here, have purchased from this seller. Also, I've never tried adding a fan.

Last edited by capkid; 04-04-2015 at 06:10 PM..
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Old 04-10-2015, 11:10 AM   #5
rlester
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Default Re: LG 42PC3DVA Plasma no picture.

Ok last night I spent over an hour trying to desolder the module. I have a solder sucker (spring loaded type) and that barely removed any solder. I ended up using wick, but still cannot get the module to budge.

It looks like I've got 98% of the solder is removed from each pin, but there must still be some there holding the pins in. I tried cutting one row of them off and using the wick some more, but that didn't make a difference.

Any suggestions? I wish I had a desoldering iron or at least knew someone with one.

My only other thought is to remove components from the top of the board surrounding the module and cut the pins all off. Hate to do that.
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Old 04-10-2015, 11:21 AM   #6
capkid
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Default Re: LG 42PC3DVA Plasma no picture.

Quote:
Originally Posted by rlester View Post
Ok last night I spent over an hour trying to desolder the module. I have a solder sucker (spring loaded type) and that barely removed any solder. I ended up using wick, but still cannot get the module to budge.

It looks like I've got 98% of the solder is removed from each pin, but there must still be some there holding the pins in. I tried cutting one row of them off and using the wick some more, but that didn't make a difference.

Any suggestions? I wish I had a desoldering iron or at least knew someone with one.

My only other thought is to remove components from the top of the board surrounding the module and cut the pins all off. Hate to do that.
I've heard of people cutting the pins - never had to do it myself. Heat gun on low setting, maybe? Also, did you try adding some fresh solder to help with flow?

Last edited by capkid; 04-10-2015 at 11:23 AM..
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Old 04-10-2015, 11:23 AM   #7
rlester
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Default Re: LG 42PC3DVA Plasma no picture.

Heatgun! I didn't even think of that... I'll give that a try.
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Old 04-10-2015, 08:10 PM   #8
rlester
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Default Re: LG 42PC3DVA Plasma no picture.

No luck. I heated it for almost ten minutes, would not come out.

I think I'm going to take the board to a repair shop that has a proper desoldering iron and just pay them a few bucks to remove it.
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