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Early Sol-20 Restore

jhalbrecht

Experienced Member
Joined
Mar 25, 2015
Messages
93
Location
Mesa, Az
A couple weeks ago I applied ECO 1000 - 1002, crowbar, to a recently acquired early Sol-20 with an original regulator board. With deRamps diagnostic assistance I replaced the TIP41, placed a 100k resistor in parallel with R12. Also replaced the power push button - there was a funky installed toggle switch and the power inlet jack too.

After repair;

  • ~300ma load 5.056vdc
  • ~2.0 amp load 4.914vdc

Previous to the R12 parallel mod I was sitting at a low 4.646VDC with a 2amp load.
There is a noticeable improvement in the, now lower, sensitivity of the 5vdc now that I've installed the crowbar mod.

ECO10001.jpg

I installed the power supply, fired it up and way cool! Got a prompt. And two or three keys also worked! ;-) That's another story...

PromptWithFewWorkingKeys.jpg

Stay tuned for keyboard saga.

c ya... - Jeff
KF7CRU
@jhalbrecht
@theRetroWagon
 

jhalbrecht

Experienced Member
Joined
Mar 25, 2015
Messages
93
Location
Mesa, Az
Sol-20 Keyboard Rebuild

Sol-20 Keyboard Rebuild

Stay tuned for keyboard saga.

RemainsOfTheDayOfTheKeyboard.jpg

This picture should be worth more than a thousand words about the keyboard repair. I'll be preparing a blog post about this in the not to distant future. Meanwhile in this image you can see the

  • Completed keyboard before reassembly. It works!
  • Sun keyboard I scavenged the new plastic, foam and Mylar assemblies from.
  • A piece of galvanized pipe I turned in my lathe to make a jig to cut the double sided tape and align the plastic for attachment.
  • Some of the old deteriorated Mylar assemblies

Check out the screen. I entered some data in RAM and dumped it out. Then typed every key and upper / lower of special characters.

Sol-20WithAmdekBeforeReAssemble.jpg

This is an early Sol-20 and apparently KeyTronic made at least two versions of the keyboard. This one appears to have used double sided tape to attach the assemblies to the bottom of the keycap assemblies, that's how I reattached. Later versions had the plastic disc snap in place. I'll get together detail of the two types you can see how the later parts have a clip to catch the plastic disc which is much less labor intensive to rebuild.

c ya... - Jeff

KF7CRU
@jhalbrecht
@theRetroWagon
 

Mike_Z

Veteran Member
Joined
Dec 1, 2013
Messages
1,620
Location
Near Milwaukee Wisconsin
Thanks for the pointers. I hope to tackle this job as soon as the snow flies around here. Till then I'll watch what you guys are accomplishing. Mike
 

jhalbrecht

Experienced Member
Joined
Mar 25, 2015
Messages
93
Location
Mesa, Az
Load and execute

Load and execute

Fun!

I entered XEQ<CR> and pressed play on my Zoom H4N handy recorder. The Sol-20 loaded Life and later Hangman and executed the program. I want to verify that the motor control circuit and relay work and test the serial port. Then I'll button it up and reclaim my dining room table.

XEQ-Life.jpg

Life.jpg
 

ef1j95

Experienced Member
Joined
Oct 10, 2013
Messages
139
Location
Philly, Yo
I currently have a Sol keyboard open, too. Much of the foam seems to be holding (barely) but a few pads have fallen apart. I was puzzled to find the adhesive membranes after reading much about the "snap-in" disks. They are more flexible and thinner than double stick tape.

IMG_0327.jpg

It looks like the metalized disks are semi-transparent where the LEDs are?

I'm not sure what I'll use for the adhesive film. I don't have a Sun keyboard, so I'll be punching out my own replacements.
 

jhalbrecht

Experienced Member
Joined
Mar 25, 2015
Messages
93
Location
Mesa, Az
My Sol-20 Restore Complete

My Sol-20 Restore Complete

A couple weeks ago I applied ECO 1000 - 1002, crowbar, to a recently acquired early Sol-20 with an original regulator board.

  • I tested the motor start / stop circuit and relays. Check.
  • I tested the Serial port as RS-232. Check.
  • Buttoned it up.
  • Reclaimed the dining room table (for awhile)

MySol-20 Restore.jpg
 

jhalbrecht

Experienced Member
Joined
Mar 25, 2015
Messages
93
Location
Mesa, Az
Icing for the SOL-20 display

Icing for the SOL-20 display

... a recently acquired early Sol-20

This Sol-20 came with a Panasonic RQ-413S cassette deck without the power cord, but happily with the audio and motor cables. While looking around on eBay I found a RQ-3090S with a power cord in a Peter Max Box. Sold! I think it will make a nice display with the Sol-20.

PeterMaxPanasonicRQ-309SBox.jpg
 

jhalbrecht

Experienced Member
Joined
Mar 25, 2015
Messages
93
Location
Mesa, Az
Selling this restored Sol-20

Selling this restored Sol-20

  • I tested the motor start / stop circuit and relays. Check.
  • I tested the Serial port as RS-232. Check.
  • Buttoned it up.
  • Reclaimed the dining room table (for awhile)

View attachment 41191

IMG_5007.jpg

I'm attempting to sell this Sol-20. I placed an add on Craigslist in Phoenix, Arizona. Hoping to sell it without ePay.

https://phoenix.craigslist.org/evl/sys/d/mesa-restored-sol-20-vintage-100/6880717265.html

I'm willing to ship in the USA with payment in full and deposit cleared up front. Buyer pays shipping. I'll have it packed and shipped at a UPS or FedEx store.

- Jeff
 
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