Quadra 700, my first color Mac!

mousehouse · May 7, 2024

As shared in the “marktplaats” topic a nice Quadra 700 came up for sale. Not super cheap but got a fair deal. Looks to be in great shape!

Keyboard and mouse are clean and working, I connected my dirty SE/30 gear to it

Theee is an interesting card in the box. Not worth anything by the looks of it, but the Q700 reports 2 displays with the second one 1024x768x256. However, the plug is not VGA but DB9…

Same as this one:

PCPC 99000016 4459 NuBus Card Apple Macintosh 1988 vintage | eBay

PCPC 99000016 4459 NuBus Card Apple Macintosh 1988 vintage | Computers/Tablets & Networking, Vintage Computing, Vintage Computers & Mainframes | eBay!

www.ebay.nl

Anybody knows this board?

olePigeon · May 7, 2024

I don't know what card it is, but in my experience DE9 is usually (but not always) B&W fixed frequency. Could be B&W portrait or two-page give how many RAM chips are on there.

halkyardo · May 7, 2024

The Bt458 RAMDAC on that card supports 8-bit RGB output, so it wouldn't surprise me if it was a colour card.

There does seem to be a de-facto standard for analogue RGB video on a DE9 connector, based on the pinout of the IBM Professional Graphics Controller - the same pinout shows up on Acorn computers, and in a few other places too. Would probably be a useful starting point for reverse-engineering the pinout if you felt so inclined:

1: Red
2: Green
3: Blue
4: Composite sync / Horizontal sync
5: NC / Vertical sync / Monitor sense
6: Red return
7: Green return
8: Blue return
9: Ground

Note that the use of pins 4 and 5 vary depending on the application.

mousehouse · May 7, 2024

Thanks! I’ll post a few screenshots of the settings panel in the Mac for reference.

I have a small scope, any way I could use it to test the signals on the port for valid video output?

halkyardo · May 7, 2024

mousehouse said:
I have a small scope, any way I could use it to test the signals on the port for valid video output?

Oh definitely - if the computer thinks there's a display attached, the card probably isn't doing monitor detection, so it'll be outputting a valid video signal even with nothing connected.

You'll be looking for a very 'analogue-looking' signal on the R, G and B pins that repeats every 16 or so milliseconds. Vertical sync will be a short square-wave pulse at about the same rate. Horizontal (and composite) sync will be a square wave pulse repeating at a much faster rate.

You probably don't need to measure each colour channel relative to its specific ground pin, any suitable ground will do.

olePigeon · May 7, 2024

First I've seen one. That seemed like a lot of RAM for a B&W card that I thought it was. Now I'm interested in what it could be.

@mousehouse Have you tried used TattleTech to identify the card? It might give you some clues like who the vendor is. That might lead you down the path to finding the drivers for it.