[comp.sys.ibm.pc] VDC750 card on the PC6300

rrr@alux2.ATT.COM (R. R. Rowe) (03/14/89)

I have recently been given an AT&T VDC750 video display controller and I
have tried to install it in my PC6300.  Unfortunately, it doesn't work
properly.  It will startup in either CGA or EGA mode depending on the
position of switch 6 on the configuration DIP switch (accessible through
the backplate).  But it can not be changed by software commands.  Trying
to do this will leave the screen blank.  The system still reads the keyboard.
I know this because I can enter the command to go back to the original
mode and the command will be accepted. 

The original video board is the AT&T P8 (came with the system) which I 
disabled by moving the jumper at W1 from pins 2-3 to 1-2 and then changed
DIPSW-1 switches 5 and 6 to on (DIPSW-1 located on the motherboard).
I have called the AT&T Product Support Center but the VDC750 is not
supported on a PC6300.  Has anyone been able to get this combination 
to work?  What am I over looking?

Here's some info:
AT&T PC6300 CPU model 3-Z (purchased in 3/87)
20MB hard disk/360K floppy
AT&T 318H monitor
MS-DOS 3.2
AT&T 4112 1200 modem board
6300 Bus Correction board from W. Allen assoc.

Thanks for the input.
Rob Rowe
AT&T Bell Labs
1247 S. Cedar Crest Blvd.
Room 1H-312
Allentown, PA 18103

(215)770-2692
alux2!rrr