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Forum Index : Microcontroller and PC projects : Mysteries of VGA ......

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hitsware
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Joined: 23/11/2012
Location: United States
Posts: 535
Posted: 04:18pm 01 Sep 2014
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Recently my ColorMax has lost 1 primary color.
The whites are sorta violet.
No big deal for my purpose.

Today I bought a KVM switch so as to go back and forth between
the the ColorMax and my Linux PC.

NOW !

The PC also exhibits precisely the same color aberation !
What's with that ?
 
Gizmo

Admin Group

Joined: 05/06/2004
Location: Australia
Posts: 5111
Posted: 04:49pm 01 Sep 2014
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Sounds like its dropped a colour signal line.

On you PC, open paint and see if you can draw a blue, red and green line. If one of them is missing, or very off colour, then you've dropped a colour.

Could be a bent pin in the VGA connector. Common.

Or, if its a CRT monitor, dry solder joints in the colour path. Usually its on the neck board, back of the CRT. There are 3 power transistors that control the colour guns, and these run warm and get dry joints. Also check around the colour driver IC, its a big IC and can get dry joints.

Make sure its been turned off for a while, the neck board has some dangerous voltages present when running.

Glenn.
The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ
 
Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5111
Posted: 04:50pm 01 Sep 2014
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Hang on, just re-read your post, re the KVM switch. So maybe a dirty connector / switch as well.

Glenn
The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ
 
OA47

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Joined: 11/04/2012
Location: Australia
Posts: 982
Posted: 05:19pm 01 Sep 2014
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Reading your post hitsware, as gizmo mentioned, I might suggest that one of the pins in your VGA connector may be pushed back into it housing or bent.

Best of luck
GM
 
hitsware
Guru

Joined: 23/11/2012
Location: United States
Posts: 535
Posted: 03:28am 02 Sep 2014
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Yep....Thanks
Just a bad monitor cable. It happened that when it was plugged directly into the PC it was bent right to make it OK. Otherwise bunk.
 
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