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Can a VGA card be installed in a PC-Portable (IBM 5155)?

djfitzgerald

djfitzgerald

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I know that certain VGA cards can be successfully installed into a PC-XT. Because the PC-Portable (5155) uses a rev. 1 XT motherboard, in theory it should be possible to install a VGA card there as well. However, the 5155 has some funkiness with the internal display interfacing to the CGA card, and (I believe) the internal display switching off when something is plugged into the external CGA port. My question: Has anyone been able to successfully install a VGA card into a 5155, and if so, which card and how?
 
I did it once just to find out if it was possible. You have to remove the CGA card and set the dip switches 5 and 6 to ON.
 
The motherboard in the 5155 will work with a VGA card as long as the motherboard has the later bios, The problem is the monitor in the 5155 is CGA mono, I believe Hugo Holden used an EGA card ? in his 5155 but can't remember what was involved in getting it to work with the 5155 monitor, he posted about it a while back. I have a 5155 and have been toying with the idea of swapping out the monitor for a VGA but haven't seen anything at a reasonable price that looks like it will fit. I like my 5155 but not keen on the monitor.
 
I suppose you could have a dual-head configuration with mono VGA alongside the CGA, if the VGA card's BIOS supports it.
 
djfitzgerald said:
I know that certain VGA cards can be successfully installed into a PC-XT. Because the PC-Portable (5155) uses a rev. 1 XT motherboard, in theory it should be possible to install a VGA card there as well.
Click to expand...
Well, certain (not all) VGA cards are compatible with the 5155's motherboard, but not compatible with the 5155's internal display.

djfitzgerald said:
My question: Has anyone been able to successfully install a VGA card into a 5155, and if so, which card ...
Click to expand...
As you pointed out, the 5155's motherboard is the first revision IBM 5160 motherboard.
At [here] is a list of known cards (to date) that work in the IBM 5160 motherboard. That web page includes a 'Requirements' section that includes relevant information.

djfitzgerald said:
... and how?
Click to expand...
1. At the IBM CGA card, disconnect the lead from the internal monitor.
2. Remove IBM CGA card.
3. On motherboard switch block SW1, set switches 5 and 6 to on. (See [here].)
4. Fit compatible VGA card.
5. Attach a VGA monitor to VGA card.

djfitzgerald said:
However, the 5155 has some funkiness with the internal display interfacing to the CGA card, and (I believe) the internal display switching off when something is plugged into the external CGA port.
Click to expand...
I had an IBM 5155 for many years, and I never saw that behavior.

The fact that you have bought this up suggests to me that you may be seeking a VGA card that connects to both the 5155's internal monitor and an external VGA monitor.
Clarify your intended monitor configuration for us.
 
modem7 said:
The fact that you have bought this up suggests to me that you may be seeking a VGA card that connects to both the 5155's internal monitor and an external VGA monitor.
Clarify your intended monitor configuration for us.
Click to expand...

Thats exactly what I'm thinking of. Basically, I love my new 5155 but its internal display has almost no burn-in and I would very much like to keep it that way. I figure that if I could get a VGA card that connects to the 5155 internal monitor as well as an external VGA monitor (that is, that behaves as the 5155's CGA card does today), then I could get away with plugging it into a modern monitor when I want to work on it and minimize damage to the internal composite display.

And by "funkiness", I meant that the 5155's internal display gets wired into the CGA card. I don't see much unusual behavior out of it.
 
You could use a "VGA to TV" adapter and connect its output (preferably via the Y pin of an S-Video output, rather than composite) to the 5155's internal monitor. It'd be ungainly and would require some wiring modification, but it would work.
 
So I havent made any progress on this yet, but I have a "good enough for niw" solution. I have been able to successfully hook the 5155's CGA card to my flat panel TV using the component video out jack. A lot of the colors dont display right, but it works good enough to use in place of the 5155's internal CRT.

Sent from the mobile client - Forum Talker
 
djfitzgerald said:
So I havent made any progress on this yet, but I have a "good enough for niw" solution. I have been able to successfully hook the 5155's CGA card to my flat panel TV using the component video out jack. A lot of the colors dont display right, but it works good enough to use in place of the 5155's internal CRT.
Click to expand...

Try finding games that support Composite CGA. They'll look even better than regular CGA.
 
djfitzgerald said:
So I havent made any progress on this yet, but I have a "good enough for niw" solution. I have been able to successfully hook the 5155's CGA card to my flat panel TV using the component video out jack. A lot of the colors dont display right, ...
Click to expand...
Have you tried adjusting the adjustable capacitor on the motherboard ?
See 'Capacitor C1' section at bottom of [here].
 
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