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1000 Series Adding A VGA Card Faxback Doc. # 16799
VGA CARD NOT BEING RECOGNIZED BY SOME VGA SOFTWARE ON TANDY 1000 SERIES
COMPUTERS.
This note is designed for the following computers:
Tandy 1000TX Tandy 1000 SL Tandy 1000 RL
Tandy 1000TL Tandy 1000 SL/2 Tandy 1000 RL/HD
Tandy 1000TL/2 Tandy 1000 SL/E Tandy 1000 SX
Tandy 1000TL/3
This note excludes the following computers:
Tandy 1000
Tandy 1000A
Tandy 1000HD
Tandy 1000EX
Tandy 1000HX
These are not upgradeable to VGA.
An article published in the September 1990 issue of PCM Magazine, on page
62, provides a utility that updates this data area to reflect the presence
of the alternate VGA adapter and monitor. The following is taken from this
article:
Not all applications will correctly recognize a VGA card installed in a
Tandy 1000 series computer. In effect, these programs are confused as to
whether you have a CGA, EGA or VGA card installed.
These problems are caused by the fact that the BIOS in the Tandy 1000
series and some other compatibles does not update the Video Display
Combination Code stored in the BIOS data area at 0040:008AH. When the BIOS
in the video card is initialized, it uses this erroneous information to
update the video display table. As a result, when an applicaion asks for
the video card and monitor type, it is given an invalid code.
There is a solution - BUILDFIX.BAS, written by PCM's technical assistant,
Greg Law. This simple, yet effective BASIC program, creates a .COM file
that can be run from your AUTOEXEC.BAT file. Note that the utility is set
up for a VGA card with a color monitor. If you are using a monochrome
monitor, change Line 100 from MONO=0 to
MONO=1.
BUILDFIX.BAS
100 MONO=0: REM Change to 1 for monochrome monitor
110 OPEN "0", #1, "VGAFIX.COM"
120 FOR I=1 TO 24
130 READ A$
140 J=VAL("&H"+A$)
150 IF I=5 AND MONO=1 THEN J=7
160 IF I=15 AND MONO=1 THEN J=13
170 PRINT #1, CHR$(J):
180 NEXT I
190 CLOSE #1
200 DATA B8,01,1A,BB,08,00,CD,10
210 DATA B8,40,00,8E,D8,B0,0B,3E
220 DATA A2,8A,04,B8,00,4C,CD,21
230 SYSTEM
Note: Type in this program in GW/BASIC and then save it as "BUILDFIX.BAS".
Run the program by typing the following line at the GW/BASIC prompt:
RUN BUILDFIX.BAS
This program will create the file VGAFIX.COM in the root directory of your
hard drive. You will need to add the following line to your AUTOEXEC.BAT
file:
CALL VGAFIX.COM
After the line has been added and the file has been saved, reboot the
machine and the fix should take effect.
PLEASE NOTE: This fix has not been tested by, nor is it supported by,
Tandy Corporation/Radio Shack.
PLEASE NOTE: While reasonable efforts have been taken in the preparation
of this information to assure its accuracy, Tandy Corporation/Radio Shack
assumes no liability resulting from the use of the information contained
herein.
(ABO/all-09/05/95)