May 012016
 

I spotted an untested Data I/O 29a programmer with Unipack on eBay a couple of weeks ago, and took a gamble and bought it.

When I received the unit I plugged it in and it powered up, but nothing was displayed on screen. The unit is meant to say “Self Test Ok” if it is working as expected, so clearly something was wrong.

I started taking the device apart, and it was fairly clear that it had been opened before as various screws were missing. The good thing about the unit is that it is fairly modular, and most chips are socketed, so I began testing each chip. I found that my ABI chipmaster failed both the 6802 CPU and 8279c keyboard controller, but passed everything else.

So I bought some replacements for both chips, hoping this would fix the issues.

Whilst I was waiting for the replacement chips to arrive, a local collector lent me his working Data I/O 29a. Although this unit had a different memory expansion board and rom set, I was able to check the Unipack, and my own rom/prom set, as well as keyboard display and that was all working ok.

Unfortunately the roms are TMS2716’s so a different pinout to standard 2716 eproms, and I had nothing to read them with to verify them or save the data from them.

The new parts arrived yesterday, and I put the unit back together with the new chips in place. I then powered on the unit and was pleased to see the message on the display say “Self Test OK”.

The next challenge is to make a serial cable for the device and see if I can get it communicate with PromLink on a PC.