Question about CGA and EGA Cards with Luggable Computer Internal Screens...

[T-Squared]

I recently bought a pair of non-working Sanyo MBC-775 luggable computers (which I do intend to fix, as it's
probably a power supply issue given the age of these computers), and I have a question regarding the screen.

The MBC-775 is a rare instance of a luggable computer using a color screen, next to the Commodore SX-64.

However, the video on the system is CGA only.
Was there an ability for luggables with a built-in CRT to use the an EGA card as a pass-through (or on-board), in essence being able to show EGA graphics on the built-in screen?

I saw this video where someone did use an ATI EGA Wonder video card in a Compaq portable, but I don't know if that's just the computer recognizing the video BIOS:

 

[rfka01]

For the Compaqs you could get their EGA cards as upgrades that had the matching connector for the internal screen in place.



Robert

 

[T-Squared]

For the Compaqs you could get their EGA cards as upgrades that had the matching connector for the internal screen in place.

Well, the computer that I have on its way is not a Compaq.

 

[Trixter]

I recently bought a pair of non-working Sanyo MBC-775 luggable computers

Congrats, I almost pulled the trigger on those, but didn't want to chance if they had major damage.

 

[SomeGuy]

The bottom line is that most portables would have to have a special card specifically designed for them with an internal connector. As shown above, Compaq made their own upgrade and ATI made a card with a Compaq compatible plug. The Compaq CGA also used a special resolution for text modes that was higher resolution than IBM CGA.

If the motherboard can accept third party video ISA cards at all, it might be possible to manually adapt an EGA card, but that depends on how exactly it is connected to their card. Post some pictures of the guts.

But something to keep in mind is that from some perspectives, the video card that shipped with it may be part of what made the system special. If I were testing software on one of these, I would want to know if it worked in their stock configuration. Also, if it has any special features, like Compaq's, those may be lost with a generic card.

 

[T-Squared]

The bottom line is that most portables would have to have a special card specifically designed for them with an internal connector.

You know, looking at the motherboard, it has something that I've seen on two different EGA video cards: a 6-pin header. I wonder if that's the upgrading connector... (In fact, one pin on the 6-pin header is connected to the video output to the CRT, which is on the lower left of the third picture.)







EDIT: I may have been premature... Some sources mark that 6-pin connector as the light-pen connection.

 

[T-Squared]

I think I found something! :D

http://worldphaco.com/uploads/FITTING_AN_EGA_CARD_TO_AN_IBM_5155.pdf

I bet I could get this to work on my MBC. I just need to make a feature connector adaptor. I don't know if the video signal works on MDA timings, but it seems good enough.

I was a bit concerned that the computer would not be able to output automatically to the video card (i.e. it prefers onboard CGA, rather than an EGA card), but I think it would, given that the IBM 5155 is a portable 5150, and clones are based on that.