Purple/Pink Lines / Postering on plasma LG 60PZ550

[Umbrella Corp]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Got it. Thank you again for all of your help!

[Jim Meinhardt]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Many thanks for all the info concerning the LG LG 60PZ550 and the problems with the cold solder joints on the coils. I had a friend over tonight to help me and sure enough mine had the same problem on both boards. We had if fixed and back up working in about 1.5 hours. I can't tell you all how happy I am to not have to buy a new TV!

[Nick's Tvs]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Tom 66

Can't believe i am posting a question about this board since I have fixed so many of these now, but I can't seem to figure out the source of the Mal-discharge I get on screen.
Board originally came in with classic cracked inductors and shorted out IGBT's. Replaced all IGBT's 2 resistors that seemed burnt and about to fail but still tested good, and finally a fuse. Made sure to reflow inductors along with C142 which is a little ceramic cap that shares a leg with the inductor pad and gets cracked as well due to heat. Anyway, plug in the set, turn the tv on, and I get some pretty bad sparkling. End up replacing IC-204 IC213 IC214 IC203 IC205 IC215 and IC216. I refllowed about half of the board, checked every single joint, and have been comparing ohm readings with a known good board and have not really found the issue still. I also swapped inductors between the good one and the bad one. I did notice that the potentiometer had a different ohm measurment, so I adjusted it to reflect 735ohms which is what the good board had from 625 ohms. Obviously still no difference.
I also made sure every single part screwed into the heat sinks are screwed in nice and tight, since I do hear a descent amount of noise/vibration I think from the board. I could not pinpoint where the vibration was coming from however.
The only thing I can think of is IC101 possibly could be causing this. It is the one on the back side of the board right where the ribbon connects in from the Logic. I would rather not replace that one yet by fear of damaging a trace or the chip itself from the known good one.
Do you think its possible that the IGBT's that were replaced are maybe faulty, or the fairchild73711 that were replaced may have had a bad one in the lot?
Any help would be greatly appreciated at this point.

[tom66]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

If you have access to a scope it would be worth using that to see what the output waveform looks like.

[Nick's Tvs]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Unfortunately I don't have one or access to one. But if its the only way to get this figured out I can make it happen. Any other ideas in the mean time?
Thanks

[Nick's Tvs]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Tom,
I have access to one, but have never really used one. I have a guy that does know how to use it however and can help me. What are we trying to measure, how, and what are we looking for in terms of results?
Thanks

[Nick's Tvs]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Ooops, forgot to update everyone on this.
If your 6 IGBT's are shorted due to your inductors arcing, and you replace them all and now start getting mal discharge, its because of one of 2 reasons.
The first board was because there is actually another set of 4 IGBTs on a different heat sink that I have never seen go bad before so never bothered to check. Or if those also are ok, its because one of the IGBT's that you replaced, you forgot to measure them out of circuit before placing them into your board (I ordered 100 or so from UTSOURCE and all so far have worked flawlessly except for this 1) and 1 of them is out of spec somehow. Replaced it and now we are back on track.
Boom! I ended up chasing a ghost all around this board for hours trying to figure out what could cause this. Finally decided to start from scratch again and that's when I noticed.

[misterears12]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Thanks for this site and those contributing here.
My set is about 4 years old but I live alone so it has gotten only moderate usage.
It develiped the pinkish horizontal band starting about a month ago.
I had built many electronic kits when I was young so I was not too fearful to open the set up.
I removed the back of my LG 60PZ550 and found and removed the PCB with the three large inductors.
I resoldered their connections with added solder and a vintage moderate power Wen soldering gun.
Then reassembled the set (checking the picture before reattaching the back) and now the set looks like new.
Thanks again for the site and excellent information!

[Troy1101]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

I am having the same problem, could I post a picture of the back of mine for you to view?

Also if my luck could not have gotten any worse, my 60PZ550 when it turns on, it turns off in 2 seconds. Any way to fix that? I was thinking of taking it to a LG tech but would rather not empty my wallet atm haha. Any and all help would be appreciated!

I'm actually having the same problem as the OP, but just today ran into this problem as well. I looked to see if Divineawakening had ever started a thread on it and he hadn't. I'm wondering if this problem was ever solved? Thanks for your help.

[Troy1101]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

I took the back of the tv off. There is a buzzing noise coming from the zsus board before the tv shuts off. There are no leaking caps or burnt solders that i can see. I'm completely inexperienced when it comes to this so I apologize for my ignorance. I'll try to post some pictures. thanks.

[canuckblue]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

I would like to thank tom for the info. My 4year old pz550 started having the discoloring so i took the back off soldered those coils and voila new picture again.

[jtschafer]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

I had the same problem with my TV and found that one of the boards had 2 cracked solder joints. I went ahead and reflowed all of the inductors just to be on the safe side. I did notice that the PCB is single sided copper (not double sided for example with thru-hole barrels. This would have made these solder joints a lot more reliable...

[Mattatl]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Not clear on what to solder. Do i reflow the half inch long lines running diagonally? On one board thereis alot of them and some are flat and some have solder raised.

[SCCrepair]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Cross-posting this from another LG 60PZ550 thread I posted to in hopes of a hasty response.

Can someone please verify the proper method to conduct the pattern test? Since this is a common fault with this model of TV, there are several threads on this forum related to this TV and information is strewn about. The TV is for a coworker and I don't want to cause any more damage.

From what I gathered, I need to disconnect the ribbon cable connecting the Control board to the YSUS board. I also need to bridge the solder pads between R51 and R52. Do I need to disconnect the ZSUS or YSUS from the supply board or make any other special connect/disconnects? Do I need to input any special commands into the remote to initiate the test or should it auto-start?

Also,does anyone have information on the LED located on the Control Board? It appears to have a repeatable pattern of blinks. Not a steady blinking, but 3 short blinks followed by a longer blink(dot-dot-dot-dash). I assume this is an error code, but I can't find any information on it's meaning. Thanks for any help provided.

[craigp_01]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Hi guys
Had the same problem with purple blotches and lines all over the screen but before I could try to resolder the joints, I lost the picture.
The TV has sat for about 3 months now and I have resoldered but I do not have any picture. There were several joints that were cracked on the Y sustain
Any ideas or advice greatly appreciated
Regards
Craig

[craigp_01]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

A bit of additional information, the TV was turning itself off prior to it becoming discoloured. It was always able to be turned back on again.
When the picture finally gave way, it happened when I was not home but my daughter said that the sound was still on. I am unable to get sound now.
I am a complete novice to this but I have nothing to lose in trying to fix it as it doesnt work anyway.
the green LED on the power supply is flashing 3 fast and 1 slow if that means anything to anybody
Thanks in advance

[Nick's Tvs]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Seems like a bad Z-sustain. Check the fuse on the board to see if it blew, and if not then check some of the transistors for shorts. The transistors you want to check are going to be the ones screwed into the grey heat sink furthest to the right of the board when looking at it while screwed in. You will see 6 of them and mainly the bottom 3 are the ones you want to check for shorts. If you don't find a short, then you may want to look at they Y-sustain.

[craigp_01]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Thanks Nick
This may seem pretty stupid and I maybe shouldnt be attempting this but are you able to provide a photo showing the fuse location. As I mentioned previously, I have no experience in this at all.
Regards

[Nick's Tvs]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Ok take a look at the following picture I have taken.
http://www.nickstvs.com/store/p477/L...Repair-Service
The first picture on the listing here has the fuse at the bottom near the middle. It is white with a a red band going through it and has 2 leads on each side that go through the board. One of the ends is slightly hidden by the heat sink.
That is your fuse and it should show a short if it is in good working condition.
If you take a look at picture 3, you will notice 3 coils with lots of overheating around them. Pictures 7 and 8 are the other side of those coils where they solder in on the back side. If you notice small cracks in those solder connections as shown in the picture above, then you most likely will have a bad Z-sustain.
Please let me know if you have any other questions.
Thank you

-Nick

[craigp_01]

Re: Purple/Pink Lines / Postering on plasma LG 60PZ550

Thanks Nick
One more dumb one. What do I need and how do I test the fuse? I did have cracks in the solder of the coils but I have repaired those and still have no picture or sound.
Regards