Today I picked it up from the seller, who lived about 50 minutes from my place. Considering the savings in shipping (this baby is quite heavy), I think I definitely got a good deal here.
After I brought it home and inspected it for any obvious issues, I decided to hook it up to my trusty old Commodore 1702 monitor. The Sol-20 uses a SO-239 video connector instead of the more common RCA type. Fortunately I have a good stock of ham radio cables and I was able to find a PL-259 to BNC adapter (PL-259 is the male counterpart to the SO-239), and a BNC to RCA cable. After crossing my fingers, I powered up the computer and it came to life.
No magic smoke appeared. In total I had the computer running for about a half hour. Feeling the air expelled from the fan at the back, I was surprised to feel how cool it was. This is a testament to a well designed Power Supply and spacious case.
The keyboard is a Keytronic capacitive keyboard. Unfortunately, these use a foam and foil type mechanism, which tends to degrade with time. This keyboard is in reasonable shape, however the 'y' and the '8', '9', '0' keys on the main keyboard are not functioning. The space bar also has issues. On the number pad, the '-' key does not work. One thing I have to do is do a foam and foil replacement. This is a tedious job, but I am getting used to it now after doing it on my Hyperion and my Apricot PC.
I have scanned the Sol Systems Manual which includes drawings and other useful information.