Picked up a "broke" Plasma to fix , good and bad lg 50pc3d

[Jimmy Nolins]

Picked this up to learn alittle more.
The Good : powers on and has display , sound . menu works

The Bad : When i turn its , slow to load picture and the picture is washed out / dull like is how i put it . no remote included .

Owner said the plasma display must be bad and not charging

I have not opened the back up at all yet but will be shortly . Might be bad Zsus or who knows . I 'll do some reading and see what i can find .
Either way beats messing with the other 42 inch plasma that had no piture at all ( thou i still want to fix that one ) Oh too many projects .

On a brightside i did fix a laptop / got a new power supply in daughters computer

[Jimmy Nolins]

BTW so far invested .. $45.00 counting gas to go pick it up

[tom66]

Yes, that is a bad Z-sustain, or a fuse on the Z-sustain. Fuses are cheaper, check them first .

[Jimmy Nolins]

Ok , took back off and trying to view /doc/16077007/LG-50PC1DRTroubleshootingManual-2007-VG-Training on scribd ( this locks my computer everytime i visit that site ) Anyways , i see the 2 fuses on the y main , and possible a non glass one also .

Should i check voltage on the plug going to the z board or is checking it at pin socket on y board a better idea ?

Last question till i can try to get the .pdf above on a different computer . I see the 2VSC TP locations and also the -VY locations on the y board .. these are not checked using chassis ground ?

[tom66]

Originally Posted by Jimmy Nolins

Ok , took back off and trying to view /doc/16077007/LG-50PC1DRTroubleshootingManual-2007-VG-Training on scribd ( this locks my computer everytime i visit that site ) Anyways , i see the 2 fuses on the y main , and possible a non glass one also .

Should i check voltage on the plug going to the z board or is checking it at pin socket on y board a better idea ?

Last question till i can try to get the .pdf above on a different computer . I see the 2VSC TP locations and also the -VY locations on the y board .. these are not checked using chassis ground ?

The problem is not on the Y-sustain.

It is on the Z-sustain.

Check the two ceramic fuses on the Z-sustain. One for the Vs is likely blown.

Check for a good Vs (approx 195V) but as you have some picture PSU is likely working well.

[Jimmy Nolins]

Thanks Tom

No fuses on Z board , f2 and f3 fuses good ... Basically same as issue here : http://www.badcaps.net/forum/showthr...ghlight=50pc3d


VA = both show 59.9 ( pins 1 and 2 of connector P805 )
VS = All 3 show 195.8/ ( pins 8,9,10 of connector P805 )

Can the Z IPM's be checked with board out like they can on The y board ? Would that be the next recommended step ?

[tom66]

Originally Posted by Jimmy Nolins

Thanks Tom

No fuses on Z board , f2 and f3 fuses good ... Basically same as issue here : http://www.badcaps.net/forum/showthr...ghlight=50pc3d


VA = both show 59.9 ( pins 1 and 2 of connector P805 )
VS = All 3 show 195.8/ ( pins 8,9,10 of connector P805 )

Can the Z IPM's be checked with board out like they can on The y board ? Would that be the next recommended step ?

Are you sure about there being no fuses? Last time I serviced a xxPCxx series LG plasma there were two fuses on the board. I haven't serviced a 50" yet, though - so maybe they aren't there on the 50" version? Care for a picture?

[Jimmy Nolins]

Sure here is fuses on Y-sustain / y-sustain / main power / Z -sustain and overall back view .

[cmj21973]

try this one

http://www.4shared.com/get/zzbg8y2j/...oting_Man.html

http://elektrotanya.com/lg_chassis_p.../download.html

[tom66]

Strange, no fuses! I would give replacing the Z-sustain a go, anyway.

[Jimmy Nolins]

Thank you cmj21973 , got the manuals

tom66 , i looked for a fuse on it for about 15 mins haha ..

Went fishing today so didn't check much , other then when Z board power plug is unpluged , i lose part of screen ......

Ok going to order a z board . Noticed that after set is off for awhile when it gets turned on , it takes about 2 1/2 mins for the picture to slowly come together to form on the display . After that i can turn it off , wait a couple mins and it shows the whole picture . Is this also zboard problem , or a mal discharge problem ?

Here is a cold start up on it http://youtu.be/8sVzcqhSkcc

[tom66]

Originally Posted by Jimmy Nolins

Thank you cmj21973 , got the manuals

tom66 , i looked for a fuse on it for about 15 mins haha ..

Went fishing today so didn't check much , other then when Z board power plug is unpluged , i lose part of screen ......

Ok going to order a z board . Noticed that after set is off for awhile when it gets turned on , it takes about 2 1/2 mins for the picture to slowly come together to form on the display . After that i can turn it off , wait a couple mins and it shows the whole picture . Is this also zboard problem , or a mal discharge problem ?

Here is a cold start up on it http://youtu.be/8sVzcqhSkcc

The Z-sustain performs two important functions: it pre-charges the display (allowing it to light to full brightness) and it erases the display on each cycle. It also sustains the display from the other end (the Y-sustain does the other part.) The plasma panel effectively sees an alternating +/-200V signal which causes it to light the appropriate pixels. But if the Z-sustain isn't working it only sees a 0-200V signal so it doesn't discharge properly.

I'm not entirely sure what causes it to slowly fill in, I expect it's to do with the inherent memory of each cell. Basically a PDP works by writing to the display with a high voltage (+380V), without lighting it up. The nitrogen in the PDP does something which makes it remember the pixel value. Then, sustain pulses are applied, which displays what has been written. Erase pulses are applied to the whole display which removes the old image and the cycle repeats. As each subpixel can only be on or off the pixels are turned on and off about 8 times in each subframe which allows for 8 bit per sub pixel colour resolution.

[Jimmy Nolins]

yep , i trying to find who to get a z board from or have fixed . Just for giggles heres the back of the z board . I have yet to test it , since i ve never checked one i want to atleast make sure i do it right .

[tom66]

There are two IPMs on this board. The sustain IPM and the energy recovery IPM. Can you post a pic of the part that says ER_LOW (and the IPM bottom side as a whole.) I'm not sure which one is failed, but you can test them.

[Jimmy Nolins]

Originally Posted by tom66

There are two IPMs on this board. The sustain IPM and the energy recovery IPM. Can you post a pic of the part that says ER_LOW (and the IPM bottom side as a whole.) I'm not sure which one is failed, but you can test them.

Thank you . I looked and a couple things looked different from what the manual i looked at said 15v vs. 18 / GRND is GND on mine so wanted to make sure i check it right .