1) The Macintosh Display Card 8/24GC supports any display that meets one of the
following specifications:
Sense pins Hor x Vert Dot Vert Horiz
10 7 4 Display Pixels Clock Refrsh Refrsh
---------- ---------------------- ---------- ------- ------ ------
0 0 1 Apple Portrait Display 640 x 870 57.2832 75 68.9
0 1 1 Apple Two-Page 1152 x 870 100 75 68.7
Monochrome Monitor
1 1 0 12-Inch Apple 640 x 480 30.24 66.7 35.0
Monochrome Monitor
1 1 0 13-Inch AppleColor 640 x 480 30.24 66.7 35.0
RGB Monitor
0 - Grounded 1 - Not Connected
Note that sense pins 4, 7, and 10 are referred to as SENSE0, SENSE1, and
SENSE2 in pinout tables for the video connectors.
None of the RasterOps 19-inch Trinitron displays meets the above
specifications. One of their 19-inch Trinitron displays has a vertical
refresh of 75Hz and a horizontal refresh of 60.241KHz. We do not think that
this will work properly, but you can try it in the "Apple Two-Page
Monochrome Monitor" mode.
Here are the pinouts for the Macintosh Display Card 8/24GC:
Pin Description
--- -----------
1 Red Video Ground
2 Red Video
3 Composite Sync
4 SENSE0
5 Green Video
6 Green Video Ground
7 SENSE1
8 Not Connected
9 Blue Video
10 SENSE2
11 Composite Sync and Vertical Sync Ground
12 Vertical Sync
13 Blue Video Ground
14 Horizontal Sync Ground
15 Horizontal Sync
Shell Chassis Ground
2) If no monitor is connected to the Macintosh Display Card 8/24GC, the card
will, in effect, turn itself off and not accelerate the RasterOps display
system. You can trick the card into thinking that a monitor is attached by
grounding pin 4. This will cause the card to accelerate other displays in
the system.