Richard Körber Brings a Commodore A1060 "Sidecar" Back to Life — with a Few Modern Tweaks

With a missing floppy, ancient electrolytics, and a damaged connector, this IBM-in-a-box needed some tender loving care.

Gareth Halfacree
2 months agoRetro Tech / 3D Printing

Vintage computing enthusiast Richard Körber has been putting a piece of Commodore history back to rights, after finding a sadly faulty unit on the used market — restoring and upgrading a Commodore A1060 "Sidecar" accessory for the original Amiga 1000.

"But what is a Sidecar? When Commodore released the Amiga 1000, its graphics and sound capabilities were unmatched in that price range. However, because the machine was based on the Motorola 68000 processor, users were unable to run existing MS-DOS software on the machine," Körber explains in a blog post detailing the restoration, brought to our attention by Adafruit. "The German Commodore factory in Braunschweig tried to solve this problem with the Amiga 1060. The machine was connected to the Amiga 1000 and provided a full IBM compatible PC."

The Amiga 1000, released in 1985, was in no way IBM compatible, which for its fans was a positive but for anyone relying on existing MS-DOS or Windows applications was an undeniable problem. The A1060 was Commodore's answer: a fully-functional PC in a compact chassis that could run MS-DOS software written for IBM PCs but display them in a window on the Amiga Workbench — sharing its keyboard, mouse, and monitor. Succeeded by cheaper add-in "bridge" boards and software-based emulation, the "Sidecar" wasn't produced in great numbers — which is why Körber snapped his unit up, despite its somewhat less than ideal condition.

"My A1060 came with an open case top. The reason was that the 5¼" floppy drive had been removed, and a full-height hard disk drive had taken its place," Körber explains. "It was so tall that it didn't fit in the case, and it was also surprisingly heavy. Many screws were missing or oxidized, but otherwise the machine was in used but acceptable optical condition. The previous owner had added a reset button on the front, and a second D-Sub connector on the back (which later turned out to be a second floppy drive connector, for whatever reason)."

Taking the system apart, Körber set about a sympathetic restoration — finding evidence of both factory-fitted "bodge" fixes for early-model flaws and aftermarket upgrades to improve compatibility. Sadly, it also revealed a damaged Zorro connector — meaning the device could no longer talk to its companion Amiga. This was replaced, the case cleaned and metal parts sanded and zinc-coated, the power supply given a full refresh, all electrolytic capacitors — known for failing in often-explosive ways — replaced, and then a few upgrades for good measure.

"I don't like empty sockets, so I organized an 8087 FPU [Floating Point Unit coprocessor]. Eight 41256 DRAM cells will upgrade the machine to the maximum possible 512kB RAM. (The famous 640kB can only be reached with a RAM expansion card)," Körber writes. "I probably only own a single 5¼" floppy disk, back from my time at school. However the Sidecar won't do much without floppies, so I decided to add a Gotek drive."

The Gotek floppy disk emulator provides a modern twist, and a major upgrade from physical floppies: disk images are stored on USB storage and selected using a rotary encoder and display, housed in a 3D-printed case and attached to the Sidecar's front air grille so as not to damage the original case. The emulator shows up as the first floppy, A:, with the physical 5.25" drive showing up as the second, B:.

A final fix for damaged Programmable Array Logic (PAL) chips, easily replaced with modern Generic Array Logic (GAL) equivalents, brought the system back to life. "I tested the machine for about an hour," Körber says, "formatted some floppy disks I bought somewhere, started Turbo Pascal. Everything worked reliably, and it was impressive to see MS-DOS running in one Amiga window and still have the full power of Amiga's multitasking to run Amiga software."

The full write-up is available on Körber's blog, along with links to the 3D-printable parts, software and manual downloads, fusemaps, diagnostic tools, and a bill of materials for the replaced capacitors.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire:
Latest articles
Sponsored articles
Related articles
Latest articles
Read more
Related articles