TRS-80 Model II Lives Again

TRS-80 Model II Lives Again

A good deal of people experienced a Radio Shack TRS-80 Model I. This was a “home computer” constructed into a keyboard that required an external watch or Television set. Afterwards, Radio Shack would update the computer system to a product III which was a preferred “all in one” choice with a keep an eye on and even house for — gasp — floppy disks. But the Design II was not virtually as prevalent. The cause? It was aimed at corporations and priced appropriately. [Adrian] obtained a Product II that was in horrible shape and has been bringing it again to existence. You can see the video of how he’s accomplished with it, down below.

The Product II was comparable to the more mature “Trash 80” which had been applied — to Radio Shack’s shock — pretty usually by businesses. But it experienced additional complex functions like a 4MHz CPU — blistering velocity for those days. It also had an 80×25 text display screen and a 500K 8-inch floppy generate. There had been also serial and printer ports common.

There were a few interesting functions. The floppy drive’s spindle ran on AC electric power and if the computer system was on, the disk was spinning. In addition, there was bank switching so you could go further than 64K and also you did not have to share your operating memory with the online video exhibit. In concept, the equipment could go further than 64K given that fifty percent the memory was financial institution switchable. In follow, the early designs didn’t have adequate growth house to take care of far more than 64K physically.

The machine experienced to have a floppy to boot and in a former movie, the computer system failed to boot the right way. Supplied it was stored inadequately for many years, that isn’t too shocking. You will get to enjoy the equipment currently being torn down, schematics examined, and ICs analyzed. Having said that, eventually, the laptop or computer seemed to resolve itself. If you have any experience with this variety of detail, you can guess what transpires next. It fails once more, of study course.

Theorizing that the elements that analyzed very good were being temporarily healed by heating, [Adrian] changed the chips, but it took a bit of function to find out it was a negative disk controller.  Once he knew the poor place, it was fairly uncomplicated to discover the terrible chips.

If you have fond reminiscences of the model I, why not build just one? We enjoy observing these outdated devices restored rather of gutted, whilst in some cases there is very little option. out?v=Qq9oRcgFnX0