🚀 go-pugleaf

Has anyone had the following 'weirdness' with Apple's 8 bit video card? :

EQUIPMENT:

	Mac IIcx
	Expanded 8bit video card
	Sony 1302 multisyncing monitor
	Shielded and unsheilded video cables

Using an unsheilded video cable everthing works just fine except that
the colors on the display are 'off' (kinda greenish). I expected this
behavior as it is identical to what we experienced on a similarly
equipped Mac II. The solution for the Mac II was to obtain a shielded
video cable. This was promptly done on the IIcx with the following
result:

PROBLEM:

The Sony doesn't appear to sync up properly to the video board. The
displayed resolution goes way down (characters are much larger than
usual and the screen image goes way off the display; the disk icon and
trashcan are off the display). There is also CONSIDERABLE flickering
in the display. On occasion, the Mac WILL sync to the appropriate
resolution, but the flicker persists. Even stranger still is the fact
the monitors CDEV in the control panel gives only 16 and 256 color
options - the 2 and 4 color options don't get listed.

The video board is indeed the problem here. Swapping boards with the
Mac II produces the same problems on that machine.

QUESTION:

Is my video board defective? (remember it works with the unsheilded
cable!) Or is this perhaps designed into the newer video boards (it
looks much different than the older board in our Mac II) to prevent
people from using multi-sync monitors, thereby gauranteeing sales of
Apple's monitors?

My gut feeling is that the video sync signal is perhaps off by some
small, but usually acceptable amount which causes the 1302 to sync
incorrectly. The unshielded cable perhaps screws up the signal (I'm an
ME by training - what's EE lingo for screws up?) just enough so that
it squeeks by.

My next test will be to see if the problem persists with a single sync
monitor (no Apple monitors around here), but we are waiting on that.


_______________________________________________________________________________
Dan Peterka                     S-Cubed                      PO Box 1620
dan@scubed.com                  (619) 587-8338               La Jolla, CA 92038