mvolo@uncecs.edu (Michael R. Volow) (09/29/90)
The top 1-2 lines of text on our monitor have disappeared!! There are no other
problems with the picture. What could this be due to?
Equipment:
Zenith Z-248 (8 MHz AT Clone)
Zenith EGA (capable of EGA,CGA, MONO) board (probably made by Sigma)
Zenith EGA monitor (straight EGA)
OEM HD controller and Seagate 4096 80 MB HD
Intel AboveBoard AT EMS board with LIM 4.0 software
What we've tried:
Replace monitor with TTL mono monitor, lines are not missing
Replace EGA board with another copy of same board, lines *are* missing
Tech replaced one board in monitor (not its motherboard) and attached monitor
to another Z248 --> lines are not missing
Return repaired monitor to original computer --> lines again missing
It sounds like either the monitor or the computer itself, rather than the
video board. What in the computer could do this. A defective memory chip in the
DOS video memory area should give an error on POST. On the Zenith's ROM Setup
there is something called "set video scroll" and it has addresses and modes as
options. Could something be overwriting DOS video memory?
Thanks in advance for any suggestions.
--
Michael Volow, Psychiatry, Durham VA Med Center, Durham NC 27712
919 286 0411 Ext 6933 mvolo@ecsvax.edu