Repairing a Xerox Alto

[nfmax]

Ken Shirriff is blogging the repair/renovation of a Xerox Alto vintage PC from 1973 (donated by Alan Kay no less) at YCombinator. Episode 5 has just been posted at http://www.righto.com/2016/09/xerox-alto-restoration-day-5-smoke-and.html, describing a heart-stopping smoke moment while using a vintage (naturally) HP 1670G logic analyser to trace microcode operation.

The Alto was the first GUI based personal computer, and introduced Ethernet to the world for the first time (the actual machine beig worked on is a slightly later version).

This project would make a great topic for an EEVBlog video interview with Dave, if it could be managed!

[DaJMasta]

I didn't read the full posts, but I got a bit and watched through the videos for each one - very cool stuff!  Interesting little tidbits of the very early architecture and already a couple of strange problems you wouldn't see fixing newer gear, and the wire wrap backplane is truly a sight to behold.

Having a single main clock for everything.... even the display refresh rate...... wow!

[nfmax]

The saga continues! It now boots, but programs are crashing when they load custom microcode and try to jump to it - . Investigating this sort of issue is what the classic logic state analyser was designed for. All those probes!

[KK]

Very cool!