Continuing work on the IBM 6715 Actionwriter 1.

After I took the dead machine apart, I first checked out the power supply, suspecting a possible blown capacitor.

Well, that wasn't it. The power supply looked perfectly healthy and generated all the expected voltages. So the next thing to check was the main circuit board.

A visual inspection of the board showed nothing obviously wrong. An electrical check of the power inputs showed no short circuits or broken connections. The next step was to gradually plug things back into the main board and see what happens. The first thing that happened when I plugged in just the power connector was a beep. That's a good sign; it means the logic is at least partially working. When I then plugged in the motors, at first nothing happened, until I remembered the cover open switch, which prevents movement when the cover is open. I pushed the button, and the motors went through their power on reset sequence. Good, next step, plug in the keyboard. Well, so long as I kept that cover switch pushed in, everything just worked exactly as it should. I tried several power cycles, just to be sure that it wasn't a one-off fluke. The machine just works perfectly, as if there had never been any problem.

At this point, the most likely explanation is that the cover open switch was dirty and dodgy, and didn't make contact after I had opened the cover to take out the ribbon. I …

A recent addition to my little technology museum has been the IBM 6715 Actionwriter 1.

There were two reasons why I chose to get this machine when I found one on sale for cheap.

First, this typewriter has been described as a bit of a unicorn. It's an IBM, but not really. IBM had been making professional heavy duty office typewriters for many decades. By 1985 these had evolved into the first models of the Wheelwriter line, big electronic devices with a separate printer unit using a daisywheel print element. However, at that time IBM did not have a suitable model for the home, school, and small business markets. Rather than build their own low end model, IBM turned to Triumph Adler in Germany, who had the successful Gabrielle 9009 electronic typewriter. Triumph Adler agreed to build the IBM 6715 Actionwriter 1 for IBM, based on the Gabrielle 9009, but with an IBM keyboard, similar to the IBM Model M keyboard used with computers at the time, and a slightly modified case. It was sold as both 6715 and Actionwriter 1, and I haven't found anyone able to say what determined what label it got in what market at what time.

Second, this typewriter has a computer interface. Now, this interface appears to have been intended as only a printer interface, but I was hoping that with a bit of trickery, it might be possible to convince the device to operate as a terminal device, much like a Teletype, DECwriter …