This article is from the comp.sys.ibm.pc.hardware.video Frequently Asked Questions, by Michael Scott with numerous contributions by others. (v1.0).
[From: Sam Goldwasser (sam@stdavids.picker.com)]
Advanced Monitor Adjustments and Troubleshooting:
READ AND FOLLOW SAFETY INFO IF YOU REMOVE THE COVER ON YOUR MONITOR.
More detailed repair info on a variety of computer and consumer electronic equipment is available from:
http://www.paranoia.com/~filipg/HTML/FAQ/BODY/Repair.html
Note that these are for advanced troubleshooting. We take no responsibility for personal injury or damage to equipment that may result from inexperienced or incompetent use of this info.
Most Common Problems:
* Intermittent changes in color, brightness, size, or position - bad connections inside monitor or inGA connector or cable.
* Ghosts, shadows, or streaks in picture adjacent to vertical edges - faulty cables/termination, video card problems.
* Magnetization of CRT causing color blotches or other color or distortion problems - faulty degauss circuitry or location near sources of strong magnetic fields or electromagnetic interference.
* Monitor not syncing on one or more video scan ranges - monitor may be incompatible with scan rates, fault in monitor electronics.
* Focus or brightness problems - adjustments needed for focus or background brightness or defective components.
* Dead monitor due to power supply problems.
Monitor Manufacturing Quality and Cold Solder Joints:
Any intermittent problems with monitors that cause random sudden changes in the picture brightness, color, size, or position are often a result of bad connections.
Bad solder joints are very common in monitors due both to poor quality manufacturing as well as to deterioration of the solder bond after numerous thermal cycles and components running at high temperature. Without knowing anything about the circuitry, it is usually possible to cure these problems by locating all bad solder connections and cleaning and reseating internal connectors. There may also be bad connections due to poor contact at the VGA connector or bad quality of the internal cable connections.
 
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