VGA card on PC6300

[Leonard B. Bliss]

I HAVE AN ATT 6300 WITH A MONOCHROME MONITOR AND CONTROLER CARD
WHEN TRYING TO INSTALL A VDC 750 CONTROLER CARD AND 319 MONITOR
USING 1.43 ROM CHIPS THE COMPUTER LOCKS UP WITH THE KEYBOARD
LIGHTS FLASHING.  I HAVE REPLACED THE 7400 CHIP ON THE OLD
VIDEO CARD AND CHANGED THE STRAP AT THE TOP OF THE CARD.  NOTHING
WORKS.  CAN A VDC 750 CONTROLER CARD BE USED AT THE SAME TIME AS
THE OLD CONTROLER CARD?CAN ANYONE OUT THERE HELP?

THANKS
LEN BLISS
ASU (APPALCHIAN STATE UNIVERSITY)
BOONE, NC
W