Jeppesen TechStar Flight Computer

I found a Jeppesen TechStar flight computer at the local second-hand store for $3.00:

I'm not sure when this unit was produced, but the manual I found on the Internet had a 1992 copyright date. There isn't anything by way of model or production information on the case, though there was an empty sticker on the back which looked like it used to have something printed on it.

I imagine these cost more than $3 originally, as they have advanced functionality for computing flight parameters. The LCD is rather fancy with a seven line display. (Ugly, but readable.)

Since I work as a flight simulator technician, I might play around with some of the flight calculation programs. But in any case it has distance, volume, weight, and weather unit conversion functionality, which makes it still convenient to keep around. There is also some kind of multi-slot number memory, though it was a bit confusing to use at first.

The unit runs on 4xAAA batteries. I do not believe the unit has an auto-shutoff function.

I opened it up wanting to see what kind of processor is inside.

Unfortunately the processor is covered in some kind of rubber or plastic. The large chip, with the rather ugly soldering job, is a MX27C256 256K-BIT [32K x 8] CMOS EPROM, no doubt containing all the program code.

I am still curious to know what processor is running this computer, but I couldn't find any more information about that in a quick Internet search.