new products during this period, memory cards based on dynamic RAM which was much denser than the older SRAMs. These began failing at an alarming rate, overwhelming the company's ability to repair them. These problems caused the company to go bankrupt, and the company was eventually liquidated on 14 May 1979. Description From the Sol Systems Manual unless otherwise noted. Physical layout Looking at the Sol-20 from the front, where the operator would sit, the keyboard was in a typical location with the main QWERTY-style layout on the left and the numeric keypad on the right. The wooden sides of the case were close on either side of the keyboard, potentially interfering with the operator's hands. On the rear right of the case (as seen from the front), directly to the rear of the numeric keypad, was the power supply, which also provided a fan to cool the circuitry. The main motherboard sat to the left of the power supply, spanning about of the case's width. The motherboard extended forward under the keyboard all the way to the front of the case. Cassette, parallel and serial ports extended off the back of the motherboard into holes in the case. Directly below the fan, was a UHF connector that produced composite video output. This could be connected to a monitor, or with a bit of work, a conventional television. The processor was near the back of the machine, with the memory and video circuits at the front. This required the video output to be routed to the back of the machine with a coaxial cable running across the top of the card. Sol bus Originally, expansion was going to be handled through an external cage that connected to the main console using two 50-pin ribbon cables. The original Altair bus design lacked signal ground pins for each of its data lines, a decision that had been made in order to reduce pin count and allow it to fit into 100-pin connectors they found in surplus. This led to noisy signals as they all shared a common ground, a topic of considerable derision by many users. When the bus was extended into a ribbon cable, the resulting signals were too noisy to be useful, and Marsh demanded that there be additional ground pins spread across the cable to reduce this noise. The Sol solved this problem by supporting only one of the