The Byte Attic B.V.Jun 27, 2024
This #SOL20 just arrived. The electronics look OK. Side panel missing entirely, as well as metal case. But it comes with lots of rare cards! This will be whole again, and restored to mint condition.
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@TheByteAttic
I have a #SOL20 with two third-party daughterboards replacing various chips on the main board. One is a Z80 upgrade, and the other allows switching between stock 64-column and enhanced 80-column display. Unfortunately there is no surviving documentation for either board. I'd like to reverse-engineer them, but I doubt that I'll ever find time.
Jun 28, 2024 at 10:24amWeb
Show threadThe Byte Attic B.V.Jun 28, 2024
@brouhaha These are simple replacements, especially the Z80, so it shouldn't have hard to reverse engineer them. If you ever want to part with your SOL-20 for fair market price, let me know.
Show thread🇺🇦 haxadecimal 🚫👑Jun 28, 2024
@TheByteAttic
Simple is relative. They required dozens of 7400 series chips. At the CPU pins, the Z80 bus is very unlike the 8080 bus, so retrofitting a Z80 to an 8080 socket is hard, and was rarely done. On all other S100 systems, upgrading to a Z80 was done by replacing the entire CPU board.
I don't know what fair market price for a "normal" SOL-20 is, but given the rarity of the Z80 and 80-col upgrades, I don't think a fair market price for this SOL can evven be established.
Show threadThe Byte Attic B.V.Jun 28, 2024
@brouhaha Okay!
Show thread🇺🇦 haxadecimal 🚫👑Jun 28, 2024
@TheByteAttic
Here is a photo showing the Microcomplex Z80 and 80-column daughterboards in a SOL.
https://www.flickr.com/photos/_brouhaha_/6693966999/in/album-72157628862392743/
top view, showing Micro Complex SOL-Z80 and Dual 80/64 Screen Mod daughtercards

Flickr
Show threadThe Byte Attic B.V.Jun 28, 2024
@brouhaha There's no photo!
Show thread🇺🇦 haxadecimal 🚫👑Jun 29, 2024
@TheByteAttic How did I manage to screw that up? I was certain that I'd pasted it, but obviously I'm mistaken. I updated the toot to add it.
Show threadThe Byte Attic B.V.Jun 29, 2024
@brouhaha Wow, four machines! There are many museums with none :P :) Cool mods
Show thread🇺🇦 haxadecimal 🚫👑Jun 29, 2024
@TheByteAttic One is fully working. Not the one with the Micro Complex stuff, alas. The normal ones will likely be reasonably easy to repair.
I haven't decided what floppy controller(s) to use. I have Tarbell single and double density controllers, and a fee others.