LCD Screen Shake - FIXED - Resistor Added 2 Sync Wire

Pixel8Arcade

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LCD Screen Shake - FIXED - Resistor Added 2 Sync Wire

I connected a Dell 19" LCD to a VGA converter. The picture displays on the LCD however it is vibrating and won't sit still.

I tried a Benq monitor with same results.
The converter is getting 5.06V

I went through the monitor menu and played with all the settings.
I went through the converter menu and played with all the settings.
Nothing worked.

Anyone ever seen this before or have a fix?

Video below shows the issue:
https://youtu.be/FRBNyhhDg1E
 
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Plug another VGA cable onto the "VGA IN" port as a dummy connection. That will fix you right up, or you can install an 8k-10k ohm resistor on the sync line.
 
Plug another VGA cable onto the "VGA IN" port as a dummy connection. That will fix you right up, or you can install an 8k-10k ohm resistor on the sync line.

I will for sure do this, but can you explain the science behind it AND have you actually done this before with positive results?

I don't doubt you, I just don't understand how it would fix the issue.
 
Yes. I have done this before and it works. It has to do with the sync signal needing to be loaded down more. Some games require it, some games don't. It's an issue with the converters.

Edit: If the VGA cable doesn't fully fix it, try the resistor on the sync line...

https://forums.arcade-museum.com/showthread.php?t=409639

I will for sure do this, but can you explain the science behind it AND have you actually done this before with positive results?

I don't doubt you, I just don't understand how it would fix the issue.
 
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Yes. I have done this before and it works. It has to do with the sync signal needing to be loaded down more. Some games require it, some games don't. It's an issue with the converters.

Edit: If the VGA cable doesn't fully fix it, try the resistor on the sync line...

https://forums.arcade-museum.com/showthread.php?t=409639

When you say place a resistor on the sync line you mean the top wire (White wire in my pic) going into the converter from the arcade harness, correct?
 

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Yes, but since you're using the converter with a Pac board, I can personally verify that another VGA cable plugged into the "VGA In" connection will fix your issue.

When you say place a resistor on the sync line you mean the top wire (White wire in my pic) going into the converter from the arcade harness, correct?
 
It is actually a bootleg Puckman board and the VGA dummy cable did not work today.

The game was on and I plugged the VGA cable into the "input" spot on the converter and the picture stopped vibrating......then 20 seconds later it began again. I tried reseating the dummy cable and tightened all connections and the picture went on shaking. I even played with all monitor and converter settings and can't get it to work. Argh.....pulling my hair out on this one.
 
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Oh. Bootleg board huh? Hmm. It's interesting how it worked for a few seconds then stopped. Try the 8k-10k resistor on the sync line.

It is actually a bootleg Puckman board and the VGA dummy cable did not work today.

The game was on and I plugged the VGA cable into the "input" spot on the converter and the picture stopped vibrating......then 20 seconds later it began again. I tried reseating the dummy cable and tightened all connections and the picture went on shaking. I even played with all monitor and converter settings and can't get it to work. Argh.....pulling my hair out on this one.
 
Hey guys - I'm going away to my cottage (tomorrow) for 2 weeks therefore I figured tonight I would put in a 10k resistor (2V I believe) on the sync line and it solved the problem for 60 seconds then went shakey again. Ugh.

Same thing kinda happened when I added the dummy VGA cable....it fixed the shake for 60 seconds, then reverted back to poop.

I guess we have 2 weeks to knock around ideas before I can work on the machine again.

My sync is a red wire (not white) btw and I think I did everything correctly. The resistor is on tight but without solder. Anyway, I made a video and posted to YouTube......

I'm at a loss for what is causing the shake. What do you guys think?


https://youtu.be/6jwulsAgdCM
 
Um? How did you wire that up? Did you Cut the wire in half and put one leg of the resistor on each side? It looks like you have the wire still connected in parallel with the resistor in the video.
 
I don't think you have your video connections wired up correctly. When the screen does show something, it's very dark and looks like red's washed out. I would say you need to get your colors correct, then worry about the sync. Why is the red wire the sync wire? You would have had to physically remove the wire from the first pin location and move it to the last. My suspicion is you have the video connection wired up all wrong. Post pictures of your video connector and how you have it spliced in with the PCB.
 
At 21 Seconds in the video you can see the connector It looks like the wire colors are all jacked up....
It looks:
Blue Green White Black Red

Like someone has pinned it wrong... BUT it does look connected properly if you follow the
R G B Bl Wh Color scheme. Then his Red wire would be Sync.
But I still say he has the wire just stripped in 2 spots and the resistor in "parallel" with the wire. IE, the wire is not cut so the resistor is between the 2 ends.

Also agreed that there is something wrong with his colors though even if it wasn't syncing it should have proper colors and this looks all red or purple.
 
Darren - I cut open the wire in 2 spots near each other and then wrapped the ends of the resistor around those openings. I'm guessing that is not the way I should have done it.
Was I supposed to cut the wire completely in half and then attach the prongs of the resistor to either side? I'm a zany noob with this mod.

As far as colours go I still need to adjust the brightness, contrast etc.
 
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Darren - I cut open the wire in 2 spots near each other and then wrapped the ends of the resistor around those openings. I'm guessing that is not the way I should have done it.
Was I supposed to cut the wire completely in half and then attach the prongs of the resistor to either side? I'm a zany noob with this mod.

Yes cut wire in 2 then install resistor between the 2 wires.
 
Yes cut wire in 2 then install resistor between the 2 wires.

Cool my friend. I'll do it correctly when I'm back from my cottage vacay. I repaired a lawn mower today and did a serious victory dance so I'm not always a complete tool with mechanical stuff.
 
This is now FIXED!

With the help of everyone on this thread Puckman is being played on location and enjoyed by the masses.

The solution was indeed putting a resistor on the sync wire. Once I connected the resistor in series (not parallel) the screen shake stopped.

I then centered the image and adjusted the contrast, brightness, colours, etc and all is awesome.

Will probably add a SLG3000 soon.

Thanks to all you KLOVERS for helping.
 
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