A View Into the Soul of the Sol-20

A project log for Sol-20 Reproduction

I am making a full sized Sol-20 reproduction, the first fully assembled microcomputer with a built-in keyboard and television output.

Michael GardiMichael Gardi 11/21/2021 at 17:032 Comments

From the beginning of my work on the Sol-20 reproduction I wondered what kind of display I would use with it. Of course a small CRT based TV or monitor would be ideal. To that end I put out feelers with my maker mates and even had someone at a local electronics recycling depot keeping an eye out for me. But after a couple of months and no success I realized I needed a Plan B.

I started thinking "What if Processor Technology had sourced and branded a monitor for the original Sol-20?". What would that look like? Well it might have looked something like this.

This design takes its cues from the Sol-20 with the wooden sides and color scheme. It has a retro CRT look while using a period correct 4:3 aspect ratio LCD panel. I my humble and somewhat biased opinion it looks great sitting on top of the Sol-20 reproduction.

The build for this was pretty straight forward. I started by laying out the side panels in Fusion 360.

I used the DXF file to laser cut from 1/4 inch plywood two of the smaller side pieces with both sets of holes and two of the larger side pieces with only the one set of holes closest to the center. Using four 1/2 inch wooden dowels cut to 188 mm and with pre-drilled starter holes in the ends I assembled the inside frame (smaller panels) with No. 6 x 1 inch wood screws.

The larger panels I sanded down and stained with the same Minwax Walnut gel that I used on the Sol-20 sides.

The funky grain patterns were a bit of a surprise but I'm kind of liking it. I could have used walnut here but balked a bit at the additional cost. Then I attached the outer panels to the inner frame with M3 x 14 mm bolts.

For the display I repurposed the screen frame that I used in my 2:3 Scale VT100 Reproduction

I had to tweak the design a bit and I added the logo but overall it saved me a lot of time to repurpose the design. I used the same display as the VT100's a PIM372 (Digi-Key part number 1778-1225-ND), an 8 inch 1024x768 XGA display. 

Th display panel just snaps into the frame. Be sure to get the orientation right with the display connector at the top of the screen frame. I printed a "caddy" for the driver board and after I connected the ribbon cable attached the board and caddy to the back of the display panel with two sided tape. 

Next I designed and printed the "skin" used to wrap the monitor.  

I attached the two pieces with glue and a brace for support.

Then I wrapped the monitor frame with the skin. If you loosen the bolts holding the larger side panels in place the skin should slide in easily. Then tighten the bolts again to hold the printed panels in place.

Finally insert the screen frame and display into the monitor.

I connected the display to the Raspberry Pi with an HDMI cable. I was also able to power the display panel via a micro USB cable from one of the Pi's USB ports. 

It was fun to imagine an alternate timeline where Processor Technology sold a branded monitor with their Sol-20s. 


Michael Gardi wrote 11/24/2021 at 18:25 point

Thank you so much Cees. Your reproductions are outstanding and I am similarly tempted to make them.

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Cees Meijer wrote 11/24/2021 at 10:30 point

This is so good,it almost hurts.. ;-) What a great idea to design your own monitor. Love the rest of your project too, by the way. Might be something I'll try to replicate in the future.

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