Seeking for the "nocga" utility or other ways to disable integrated CGA \ VOGONS

Seeking for the "nocga" utility or other ways to disable integrated CGA

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First post, by montezuma iii

Posted on 2025-09-26, 23:16

montezuma iii Offline

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Dear guys and dolls,
Hi:
I've got a Frael King PC, with NEC V20 cpu and CGA integrated graphics: I'd like to install an external 8 bit isa VGA card and I think I've to disable the internal CGA chip:
Chatting with ChatGpt It saids to obtain the "NOCGA" .exe (or .com) utility, wich I'd find in software packages like Norton Utilities, PC DOS 5/6 OEM installations, Checkit, Sysinfo or whatever: It hasn't a precise info about where to find It.
The point is right this: where could I find It?
Or are there others ways to disable the CGA chip? Could I remove It or I'd do damages? (but It's an SMD chip and I'd have to bring the pc to a reparation center); Should I remove the Video RAM chips too?

Thank You very much indeed for the help.

Reply 1 of 7, by konc

Posted on Yesterday, 07:17

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I'll risk a guess here and assume that chatgpt is hallucinating as usual referring to the MS Basic compilers NOCGA.OBJ file. If you weren't targeting CGA systems you'd link this file to exclude things you didn't need, thus reducing size.

Also please don't butcher it to remove the chip!

Reply 2 of 7, by Jo22

Posted on Yesterday, 07:50

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Hi there. This seems to be the computer, I guess?
https://www.valoroso.it/frael-king/

There are screenshots of the motherboard..
I spot a jumper to select between PAL TV and TTL Monitor? Maybe that's CGA/MDA or CGA/Hercules switch?

If so, the latter setting might be more compatible with co-existing with VGA..
Because, a Hercules/MDA card in plain text-mode merely use 4 KB of RAM and doesn't collide with A-segment used by EGA/VGA.

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In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Reply 3 of 7, by Predator99

Posted on Yesterday, 09:53

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Does your pc see the VGA Bios? Type
debug
d C000:0
And show us the output.

Reply 4 of 7, by montezuma iii

Posted on Yesterday, 21:40

montezuma iii Offline

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Hi there. This seems to be the computer, I guess?
https://www.valoroso.it/frael-king/

Yes, the link is right.

Predator99 wrote on Yesterday, 09:53:
Does your pc see the VGA Bios? Type debug d C000:0 And show us the output. […]
Show full quote

Does your pc see the VGA Bios? Type
debug
d C000:0
And show us the output.

Yes: I can see the VGA bios at boot, and:

"reserved for IBM compatibility.....10/18/93........D4.01E..........Copyright 1988-1991 TRIDENT MICROSYSTEMS INC."
It's a Trident TVGA9000i-1, 8 bit ISA; It outputs in black and white, no graphics mode, only text: the games doesn't start.
In some sporadics moments It shows the VGA BIOS writings at boot in colours, but I don't remember if It continues to boot, and if It does It in colour mode.

Reply 5 of 7, by Predator99

Posted on Today, 06:20

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Then I agree with Jo22 there might be a resource conflict. Is there a BIOS Setup where you can disable CGA? Can you provide a dump of the ROM?
Your Idea to remove CGA ram is also an option. Its on a socket? If yes there is no risk to try without.

Reply 6 of 7, by wbahnassi

Posted on Today, 09:29

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Randomly starting with color or monochrome reminds me of a known Trident issue that happens when connecting it to monitors newer than its time. IIRC it was trying to determine the monitor's type (color vs mono) via a data pin that got repurposed on newer monitors, so it seems it gets fed "random data" at boot, hence the random choice of color or mono.

I suggest trying a different VGA card. The fact that the VGA card POSTs means the integrated CGA is cooperating properly.. so I think you don't need to tinker with jumpers even.. just the mono/color switch on the back of the mobo.

Turbo XT 12MHz, 8-bit VGA, Dual 360K drives
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Intel 486 DX2-66, CL5428 VLB, SBPro 2, 2x CD
Intel Pentium 90, Matrox Millenium 2, SB16, 4x CD
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Reply 7 of 7, by jmarsh

Posted on Today, 09:57

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Well known problem with TVGA cards misinterpreting a DDC signal as random high/low/color/monochrome, trident's smonitor.exe utility will force the card into color mode. Nothing to do with the onboard CGA.

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