DT-III Portable Computer

[Really bad picture of the DT-III Portable Computer]


MODEL  DT-III Portable Computer
BITS  16
CLOCK SPEED  4.77 or 10 MHz
RAM  640k
ROM  8k

I wanted an XT or AT class machine that was quick to set up and put away so I could relive my late teens using such a machine to program. My dreams came true when I saw a portable for sale on eBay. I put a watch on it, hoping nobody else would be interested. For some reason I thought it was a Compaq but couldn't find any information on the DT-III model anywhere. It was only after I won it I realised that the Compaq logo wasn't anywhere on the unit and I was only fooled by the similarity of the lettering. Yes, this is somewhat a clone or, at best, a lookalike.

This didn't bother me really. The make and model didn't matter as much as the functionality. If anything, I could justify a bit of tinkering as it's so generic that keeping it relatively original was now not so much a priority. I pulled it apart to find it had a Japanese made "Turbo" XT motherboard switchable between 4.77 or 10MHz. I was pleased to find that the CPU installed was an NEC V20 which is practically an 80188 in an 8088 pin compatible DIP package that can also execute 8080 instructions. Neat!

When I got it, it only had two cards installed, one of which is for the 20M MFM hard drive. The other card provides the floppy controller, Hercules compatible graphics, an RS232 port, a parallel port and game port. The built in 8 inch amber monitor is pretty damn cute too. I have since installed an Intel 8087-1 FPU as well as burning an open source 8088 XT BIOS to EEPROM for it that displays CPU and peripheral information before booting.

The hard drive wasn't working when I first powered it on and then it mysteriously sprung to life later on. It makes the coolest "zzzzzzt zzt-zzt" sounds whenever you access it. Still, I ened up unplugging the power to it and replacing its controller with an XT-IDE card with built in compact flash slot. This not only makes it easier to transfer files from it to a modern computer, but it allows me to have different operating systems on various compact flash cards that can be swapped in and out with ease.