Under Performa
Connect a vintage Mac to a VGA monitor
My first encounter with the cheapskate design of the Performa 6200 came when I turned it on. The power ‘button’ is just a partially cut out circle in the back of the case. When you push it, the plastic flexes just enough to nudge against the actual switch on the inside. Spoilt as I am, by the exquisite attention to detail of modern Mac designs, I didn’t initially realise that this wretched nubbin was actually the ‘on’ switch. And when my first disbelieving prod wasn’t firm enough to close the circuit, I almost wrote the machine off completely. Blind testing But, for better or worse, it seems that my Performa 6200 does in fact start up. Or at least I assume that it does. For my initial test, I only had the chimes, beeps and hums to go by because I didn’t have a monitor connected. Macs of this period use the DB-15 video connector. This uses the same number of pins as the more common DE-15 VGA connector, but the plug is wider and only has two rows of pins instead of three. Although I have several monitors from the Haq Collection that have DB-15 ports, none of them came with any cables. DB-15 cables are actually pretty hard to find nowadays – all the sources I could find were in the US, with delivery times measured in weeks. If I was going to hit my deadline for this issue, I needed to make my own.
But there’s an additional complication. Since I don’t have a monitor cable, I haven’t been able to test any of the Apple monitors that use the DB-15 port. If I go to all the trouble of soldering up a monitor cable and then plug it in and nothing happens – is it because my cable is faulty or because the monitor
is dead? This is a fundamental
principle of troubleshooting computer problems. You must design your tests in such a way that you learn something whether the result is positive or negative. Testing two unknown things at the same time only tells you something useful if they both work. If either or both of them don’t, you have gained nothing. Cable knitting So I decided to detour slightly and make a cable to connect the Performa 6200 to a VGA monitor that I know works. The snag is that the pin-outs are different for the two socket types. I found a great diagram showing how to convert between them at old.pinouts.ru and used patch leads to run a wire from each pin on the 6200’s video port to an electronics breadboard. Then I carefully mapped out which wires should run straight, which were crossed and which weren’t connected at all, and ran another set of patch leads from the breadboard into the VGA port of the monitor.
It was a bit more fiddly than that, because patch leads have a tendency to wiggle slightly and so the connection on some of the pins was a bit intermittent. Modern monitors will just display a blue screen until the video signal is completely stable for at least a few seconds, so you don’t get any feedback to let you know which pin is loose. But eventually I got something reliable enough that I could see the Mac OS desktop, provided nobody slammed a door or spoke above a whisper. Since it was 2.15am by this point, I went to bed triumphant. And in the morning, the postman delivered a parcel from our glorious benefactor Tim Haq that contained a DB-15 monitor cable. So I needn’t have bothered.
And after all of that, is there any point in having this Mac? Well, not to get any useful work done. There is no app this can run that I couldn’t run much faster and more conveniently from inside an emulator. But I don’t have any other machines running System 8, and it has both a floppy disk drive and a CD-ROM. It’s just possible that this clumsy and ill-regarded middle child might still earn its keep shuttling files between its prettier brothers and sisters, both older and younger.
I could see the Mac OS desktop, provided nobody slammed a door or spoke above a whisper