Restoring My Original Workstation

The fall semester of 1991 saw the completion of the computer I used for the first half of my college education.

1) The Amiga 500 outfitted with 1MB of chip ram after a minor motherboard modification 2) The GVP Impact Series 2 A500-HD+ SCSI DMA controller with 2MB fast memory 3) A Quantum Fireball 50MB SCSI Hard Drive 4) A Phillips 13” Monitor

It was a great machine for word processing papers, writing code for EE/CS and math classes, lurking Usenet via dial-up, and some gaming to pass the time.

Shortly after the introduction of the Amiga 1200, the complete setup was sold to my brother. He kept it running for most of the 90s until a mishap shorted out the A500-HD+ and he upgraded to an Intel box. The entire kit minus the Phillips monitor came back into my possession after cleaning out our mother’s attic.

The original Amiga 500 and a parts machine that was acquired from a former local dealer when they were going out of business has been in my storage shop for sometime. A Commodore 1084 and monitor cable had also been secured a few years back when I first entertained setting the system up for some retro-gaming. It was shelved when the A500-HD+ proved to be beyond the available level of interest at the time to get running again.

Enter the Modern

Recently I’ve built up a pretty solid hobby workbench with the intent of building and repairing electronics again. Armed with having the equipment to deal with most issues in through hole electronics, I decided to track down a working A500-HD+. Everything has been assembled and partial success has been achieved.

Initial Results Running

Quick Condition Assessment

After powering up the monitor, drive controller, and the Amiga I was presented with the Workbench disk screen. This indicates that even though the included SCSI hard drive spun up, the Amiga 500 is not able to find a bootable image. As shown above though the system does boot into Workbench 2.0 from a floppy. The four 1MB DIMMs populated in the new A500-HD+ do register as fast ram unlike the original 1991 unit.

More serious issues may be present in the Amiga 500 now however. When booting Workbench from floppy the console was receiving asterisk characters from the keyboard with nothing pressed. Backspacing did remove them and allowed things to continue. Sections of the keyboard appear to not be responding at all. The mouse has vertical but not horizontal movement and the rollers appear clean so this could be an electrical issue as well.

Future Plans

This weekend’s project will be ensuring the device drivers for drive controller are installed or if swapping back in the original 50MB Fireball helps. Digging into the I/O issues on the Amiga will come later, since it will need to spend time on the workbench to troubleshoot whatever is going on there. Follow along for future installments as I get this old machine up and running.

Finally, attention will be turned to the original GVP A500-HD+. Having a known working until should help to troubleshoot the original issue. Then if possible get it repaired and running with the parts machine.