So today I had a bit of time and a pile of parts. As a result I made up a very simple adapter for the Apple IIgs allowing me to connect the D15 RGB connector to a VGA monitor.
It’s a pretty easy job. A straight “connect green to green” affair. So of course I managed to screw it up. Unfortunately I misread the pin-out, and got it left-right inverted.
Thankfully the middle pins on a VGA connector are enough that at least the blue video signal gets through, so I was immediately able to see my mistake. After a bit of cursing, and breaking out the soldering iron, I’d flipped the remaining pins and, yay I had full colour.
I was a little concerned initially about whether my monitor would cope. The Apple IIgs puts out a 15KHz vertical signal, and most monitors don’t like that. Now my monitor does support 15KHz (it’s why I purchased it in the first place, mostly so I could use it with my Amiga, but it’s also worked well with my Atari ST) but I’d read that it did “Non Standard” signalling. Thankfully the picture was fine.
The next thing to do is make a plastic shell that will make it neat. I’ll buy the bits for that when I get a chance. I’m figuring I’ll buy a shell for a 15 pin connector, and one for a 9 pin connector and epoxy the two together to make a nice “all in one” shell.