LG Monitor with Lines (big pictures)

cyberfluxor

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Thank you in advance for checking out my issue.

This is a newer LG Monitor ('07?) that is throwing lines across the monitor regardless of the game connected. Adjusting the brightness helps, but then it will jump to an all black screen before the lines disappear. I cannot recall the model (just noticed the tail of the model # on the neck), but am providing some close-up pictures as maybe someone can identify where something needs to be adjusted or what needs to be changed as I believe this is an easy fix but was informed it may need a new board (hope not). Monitor has some 50 hrs of use.

PacMon1.jpg

Monitor picture

Pac-ManMonitor2.jpg


Pac-ManMonitor1.jpg
 
Last edited:
Some additional details.

When you turn the screen drive knob (whatever it's called) on the flyback up, the picture will appear but you can see the scanlines. You can turn it down almost to the point where the scanlines disappear, but it's right on the border. Turn it down any more, and the whole image disappears.

We tried turning the brightness on the handheld adjustment PCB all the way up, and turning the flyback drive pot down, but the image still disappears.
 
What if you ......

Unplug the video input. (RGB G Sync)
Set the brightness and contrast to about halfway.
Then adjust the SCREEN up on the flyback and then back down to where you just get a black screen, no lines.
Plug video input back in.
 
This looks like a version (or copy) of one of the Vision Pro's made by Kortek (even down to the sync selector button).

While it has very low usage, it's possible it was made with some of the bad caps that came out a few years back and were used often by the low-bidders who built these things....
 
What if you ......

Unplug the video input. (RGB G Sync)
Set the brightness and contrast to about halfway.
Then adjust the SCREEN up on the flyback and then back down to where you just get a black screen, no lines.
Plug video input back in.

Just tried that. Same thing. Adjusting screen drive down and parked brightness/contrast in the middle. No picture without game signal connector plugged in, no picture with it plugged in. The picture won't show up until it's cranked up. Literally, the whole picture just disappears.

Odd.
 
This looks like a version (or copy) of one of the Vision Pro's made by Kortek (even down to the sync selector button).

While it has very low usage, it's possible it was made with some of the bad caps that came out a few years back and were used often by the low-bidders who built these things....

Yea, I was thinking that originally. But the monitor is made in 2007, one would think that it would be past the failed caps, but it's probably a good place to start. I'll ask cyberfluxor to get a cap kit :)

None of the caps are swollen, but that doesn't always tell.

Supposedly less than 50 hours total on it.
 
This looks like a version (or copy) of one of the Vision Pro's made by Kortek (even down to the sync selector button).


Yep, I'm going with Vision Pro.....L/G is who made the tube.
You can see the model number in the one picture...MTG-2901.....also, it's a Tovis re-brand. You can see the Tovis name by the filter cap.

Edward
 
So the fix on the monitor was a transistor replacement, which on the lucky side is a common component so the part was on hand. Two issues persist:

1) When the monitor is in place there is an EMF discoloring the screen and it appears to be coming from the direction of the PCB. I removed the speaker as it was busted to begin with and appeared to be emitting a large enough field to distort the picture as well. Is there a suggested method of combating this issue or maybe something is just wired wrong? I plan to continue investigating this and replacing the speaker shortly.

2) The glass top to the cocktail and artwork appear to be $150+ from most places. Is this the actual going rate and is it much cheaper to just get the glass fabricated? Also the clamps appear to be $28-60, which seams quite steep since most clamps are much cheaper. I plan to look around but was curious if people have ideas about this.

... Moderators, this thread can be moved to the "Restorations, Cabinets, and Cosmetics" sub-forum since the bad monitor issue seems fixed.
 
Just a solid detail on the monitor. The 7812 power regulator had been replaced with a cross reference. It was producing ~11.5 volts, which was causing the issue. Obviously it had been replaced in the past. One thought is to add a heatsink to it, if it is getting really warm.
 
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