NEW life for old  printers

Luis tries to churn out introspective essays on retrospective printers

The smaller of the two printers is the Apple StyleWriter.

This was introduced in 1991, back when I was still printing on dot matrix printers with an ink ribbon. The ink cartridge will definitely have dried out to worthlessness by now, but compatible Canon cartridges are still quite easy to get hold of. Less easy to replace is the AC adaptor. I looked through all the boxes of cables and oddments that came with the Haq Hoard, but there was no power brick with a barrel jack that fitted the printer. The boilerplate markings on the underside of the printer state that it requires 9.5V DC. Although I have a ridiculously large collection of ‘wall wart’ AC adaptors, none of them output precisely 9.5V. However I did find a 12V adaptor with the correct size of barrel jack.

Provided you have a power source that is at least 2V higher than the voltage you need, you can always convert it to a lower voltage using a ‘buck converter’. This is a solid-state device that essentially switches the power on and off extremely quickly to reduce the effective output voltage. I use these all the time for Arduino projects, and I have a bunch of them that are tunable. You turn a little adjuster screw on the top to dial the voltage down to whatever you need.

Barrel of fun

I cut the barrel jack connector off to splice in the buck converter, but stupidly, I forgot to check the polarity of the connector first. In most devices the sleeve of the connector is ‘ground’ and the inner tip is the positive connection, so I soldered in the buck converter with that assumption. The converter has a blue LED that normally shines annoyingly bright when it is powered up, but as soon as I plugged in the printer, the LED went out. Unplugging it lit the LED again, so at least I hadn’t blown the converter, but why was it losing power? The StyleWriter uses 23W of power. At 9.5V, this means it draws 2.4 amps. The converter is rated for 3A and the power brick for 2A. Technically, I was overloading the adaptor by 20%, but there ought to be enough headroom for this to have worked, at least for a short while. I tried swapping the polarity on the barrel jack connector, just to make sure but still, no dice. Conclusion: the StyleWriter has an internal short circuit somewhere.

What about the LaserWriter, then? Its condition is much worse, with very nasty corrosion on the internal rollers. But when I plugged it in, it made some very promising whirring and humming noises, so I was encouraged to press on. The paper tray

was jammed shut so tightly that I was convinced I’d missed some hidden catch to unlock it. It was only when I became so desperate that I didn’t care about breaking it that I pulled hard enough for it to finally pop out. Along with my shoulder. There seemed to be plenty of toner left in the cartridge, given the way it leaked out onto the floor. The LaserWriter has connectors on the back for a Centronics parallel cable, and 25-pin serial, but my Mac/SE seems to expect the printer to be networked over AppleTalk. I have an old AppleTalk cable, but it has evidently been mistaken for an ADB (Apple Desktop Bus) cable at some point in its life. Although both cables have the same mini-DIN plug, they use different numbers of pins. Forcing the 8-pin AppleTalk cable into a 4-pin ADB socket had squashed the extra pins flat. I tried straightening them out with a pair of needle-nose pliers but, to nobody’s surprise, the bent pins promptly snapped off. Luckily, an eBay search and £8.99 will still get you a new AppleTalk cable today.

My Mac SE recognised the LaserWriter immediately, and I watched excitedly as the green LED on the printer front panel flashed to show it was receiving my document. For 15 seconds I actually dared hope. Then the flashing green was replaced with flashing yellow, which means ‘call a service engineer’. It turns out that it isn’t just the tray that is jammed. The entire paper feed mechanism is rusted solid. Back to saving my jottings on floppy disks, I guess.

When I plug it in, it makes some very promising whirring and humming noises…

The LaserWriter, however, is electrically sound, but delve a little deeper and it’s rustier than a sunken U-boat.

The StyleWriter is in excellent mechanical condition, but it suffers from a strange electrical fault.

The flashing yellow light of doom is not what you want to see. This translates to ‘call a service engineer’.

If your AC adaptor doesn’t supply the right voltage, you can splice in an adjustable buck converter.

Squashed pins: unfortunately, the AppleTalk cable appears to have been mistaken for an Apple Desktop Bus cable.