Instructables Sol 20 Reproduction

Not meaning to spam, but has anyone seen this yet? .Sol-20 Reproduction : 16 Steps (with Pictures) - Instructables


Is Reproduction the right word here, as it is a PI emulation of a Sol-20, as reproduction implies more a hardware than software revision. The case and keyboard look good.
True reproduction is rather hard for that era of computing, with 1024 x 1 ram
and no support chips for video or serial I/O with the Z80 till about 1979.

Michael Gardi also made the VT100 replica discussed here: VT100 simulator and 3D printed case

His Making a Sol-20 Emulator : 10 Steps (with Pictures) - Instructables page says “While detailed schematics and board layouts for the machine exist, the cost of reproducing a Sol-20 PCB and populating it with “vintage” parts would be prohibitive. So I decided to emulate the machine’s hardware in software.

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I use the term reproduction because it implies “close copy” whereas replica or duplicate typically mean exact copy.

Seems like an excellent project to me @MICHAEL_GARDI - welcome to the forum.

I was the support manager for a chain of computer stores that sold Processor Technology. I was factory trained by PT to maintain and repair SOL20 and their associated Helios 8" floppy systems. There were 2 major problems with the SOL20 - 1 being the riser card that the S100 cards would plug into. There would be a lot of intermittent connections causing system crashes. 2- The 4K dynamic memory cards sucked. There were timing problems in the refresh. If you replaced them with static ram cards you were good to go,
The Helios disk drives were manufactured by PerSci and unlike most of floppy disks drives that used stepper motors for positioning the heads, the PerSci drives used voice coils just like their big brothers the hard disk. They had to be constantly aligned regularly maybe because they were mounted vertically not horizontal. Still have my Processor Technology coffee mug!

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I love first hand accounts like this. Thank you for sharing!

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Computer history podcaster Sean Haas has made two episodes about the “wedge” form factor, and the SOL-20 features prominently.

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Thanks for the tip Lars. The episodes were great and I have listened to some of the others as well.