Compaq Portable II contrast run issue (I think)

[FlyingScotsman]

Hi guys, this is my first post on here, so sorry if my netiquette is not quite right. Here is my problem, I have a Compaq Portable II 286 computer running at 8 MHz. I am having an issue with the screen. Basically white (or green) on black text looks perfectly fine, but if any graphics are displayed, the white (or green) areas run off at the right hand edge. I've tried messing with all the screen controls (including those inside the case), re-seating the video card, and re-plugging the monitor into the card. What could the problem be? I am wanting to rebuild this machine. Thanks a lot.

To try to better explain it's affliction I am enclosing a link to my video of this machine
http://www.youtube.com/watch?v=eKLXHRWx_xs&feature=plcp

Thanks in advance for your help

 

[modem7]

Welcome to these forums.

One possible cause of irregular left/right borders is poor power supply regulation.
Have a read of the earlier thread of http://www.vintage-computer.com/vcforum/showthread.php?24129 (from about post #12 onwards)

 

[FlyingScotsman]

Thanks a lot, I will do. It is nearly a 30 year old computer, so it could quite easily be that

 

[modem7]

Note that if the cause of poor regulation is a faulty filter capacitor/s, that capacitor isn't necessarily in the PSU. It could be in the CRT unit.