Model 8570-A21

Model 8570-A21

Another hamfest find...this machine was sitting in a sad looking pile of PC/XT machines and some clones. It didn't look like much of a gem itself, but I stopped to inspect the type-model number and grabbed it from that pile of ruin quickly after seeing the A21 type.

The A21 is the last generation of the Model 70, with a 25MHz 386 CPU fitted onto a "cardplex" that fits into the system board. This same board can also take a 486 CPU and some systems came with that preinstalled instead. Since these machines were impressively powerful and expensive at the time, not a lot of them are to be found just sitting around...and the 486 version is supposed to be the first-ever released 486 powered computer.

The machine looked positively awful on the outside, but the insides (what really matters) turned out to be undamaged and--unlike the better looking machines I picked up--this little 70 started right off with no problems when I first turned it on. The casing looked like it had been dumped in the mud, maybe had a little blood on it and plenty of dirty black streaks.

I had no luck cleaning it with the regular batch of glass cleaner and pumice cleaner, so I just pulled all the circuitry out and threw the casing into the dishwasher. As you can see in the picture, the machine came out looking brand new...a remarkable recovery!

The hardware configuration of this machine is as follows:

Texas Instruments 386>486 clock-doubled upgrade CPU (50 MHz)
6MB RAM on the planar (maximum of 8)
Single 1.44MB floppy drive
8514/A Display Adapter

For software, I elected to install PC-DOS 7 and Windows 3.1.