Lg 42pc3d weird picture.

[Malachi]

Re: Lg 42pc3d weird picture.

The seller is sending out another zsus, told me I don't need to return the old one so I guess I can try to fix it.
I watched a YouTube video on the repair but it didn't show how you get to it. Do I unsolder the heatsink from the board? Seems the only way as there are screws from the bottom but can't be accessed till the whole thing comes off.

[Alastair E]

Re: Lg 42pc3d weird picture.

Easiest way, takes 20 seconds max--IF YOU ARE NOT WORRIED ABOUT THE IPM--


Neanderthal Method--

Take large flat-blade screw-driver and break IPM from board, using screw-driver as lever.
--Then desolder each pin stump one by one.
--Board will not be damaged unless you are foolish and use a sharp ended screwdriver that digs into board, the IPM pins pull off the IPM print carrying the plastic strips each side.

Motor-Mechanic method--If you want to Re-Use IPM/Repair it.

Take two 4" pieces of 22mm copper water-pipe and flatten them. Screw the two flat copper strips produced together one on top of other, making a sandwich, the sides closely mating.
Hold in clamp-wrench approx the middle and heat with blow-torch till solder will tin the edges where the folded copper pieces meet, Then heat till flame glows green and apply to all the IPM pins on one side at once--the pins will nestle in the groove made between the two coppers, add some solder making sure all pins get some, leave for a few seconds for heat to soak through, then carefully lift that one side out from board. No Force is needed.

Re-heat and do same other side.... Takes about two minutes (With MAPP-Gas, bit longer with Butane)

Clean up the board as usual, HOT iron needed as the heatsinking effect of the board/print is something fierce with these multi-layer thick copper print boards, and the main reason its such a huge chore to remove one with standard issue tools!

[dick_barton]

Re: Lg 42pc3d weird picture.

You're as smart as the next guy. Once they didn't know how to either.You learn and keep learning. With trying and failing you learn and gain knowledge.

One of the best service engineers I ever worked alongside was self taught later in life. If you really want to do something badly, you will be quite surprised at how it all comes together.

[Malachi]

Re: Lg 42pc3d weird picture.

I just used the somewhat brute method. First I tried to unsolder it. Hoping it would fall right off but I guess not enough solder was removed.
Then I used the screwdriver.
The video I watched showed the guy replacing Q1 and Q2. They both have dark spots in them.
But I'm pretty sure this IPM is un repairable.

[Malachi]

Re: Lg 42pc3d weird picture.

May well have been repaired--But, NO NEW IPM's exist--LG Never sold 'em separately!

ALL the IPM's Everywhere are recovered from used boards....

Your 'new' IPM could well have 20,000 hours on it--and be on its last legs due to Black-Pad Syndrome....

eBay has these IPMs for about $25. Including shipping.
Alastair said no new ones exist. These are labeled new, of course they are from China...
Lol.

[Alastair E]

Re: Lg 42pc3d weird picture.

Yup--Ive bought those, VERY careful examination will show minute traces of heatsink compound, witness-marks from screw mounting--but more importantly--the id mask near the transistors/big diodes has turned pinkish/purple instead of being white like that at cooler parts of the circuit....
Ones Ive bought did work however....

Be aware--these fail in two ways. One you know. Other is where they become intermittent and give a flickering/grey picture. Sometimes this preceeds self-destruction and short-circuit...

All because the substrate is -gold- plated causing black-pad over time heat-cycling....

[Alastair E]

Re: Lg 42pc3d weird picture.

Here you go--Same stuff, bit cheaper--

http://www.aliexpress.com/af/yppd%25...ext=yppd-j018c

[Malachi]

Re: Lg 42pc3d weird picture.

Here you go--Same stuff, bit cheaper--

http://www.aliexpress.com/af/yppd%25...ext=yppd-j018c

Thanks but like you said, still used. Installing one seems easier than repair on one as the guy did on YouTube.
Can I use the same thermal compound as I use on CPUs?

[Alastair E]

Re: Lg 42pc3d weird picture.

yes--any good thermal-paste will do, just dont make it too thick or come into contact with the pins--Some of the grey type over time can conduct at the high voltages on IPM's...

Good S/H is about all there is--Unless you can find an unused new complete X--They do exist but obviously--Expensive....

[Malachi]

Re: Lg 42pc3d weird picture.

I got another zsus board in exchange for the first faulty one, checked the fuses before puttin it in and they are good.
Turn the tv on, screen is brighter by still not right. A few seconds after turning it on there is a loud pop from the speakers and the set turns off.
The fuses on the ysus are good.
Not sure what is next.

[ReeceyBurger123]

Re: Lg 42pc3d weird picture.

Seems like Ysus Ipm to me then if it went bang. I have a PX5D here same panel and sus boards though faulty Zsus Ipm causing red MD over screen.

[Malachi]

Re: Lg 42pc3d weird picture.

It does have reddish tint. It goes bang through the speaker. Also it's repeatable. I can turn it back on and it will do the same thing.
Also why does it not do that when there zsus is not connected? It will stay on then, with no noise.