Here is the front of the factory power supply that is part of the SCELBI-8B system described in the last post. A simple on-off switch, three banana plugs/binding posts, (+5 volts/-9 volts/ground) and an Amphehol 4 pin socket for connecting power to the chassis make up the controls and connections on the front. On the back is a fuse and fitting for passing the AC power cord through the back of the chassis.

The inside reveals space at the top of the picture for a 110 volt AC fan which is bolted to the cover. The cover has ventilation holes drilled in both ends to allow the fan to draw in cooling air. Two Power-One supplies make up the power supplies. One is 5 volts and the other is a Power-One 12-15 volt supply modified to output 9 volts. The positive output of the 9 volt supply is connected to the negative output of the 5 volt supply which becomes ground for the system. The negative output of the 9 volt supply becomes -9 and the positive output of the 5 volt supply supplies +5 volts to the system.

All in all, the whole thing is an extremely simple affair, the only complication being the changing of a resistor in order to covert the 12-15 volt supply to a 9 volt supply. This unit did not actually use banana plugs for power delivery to peripherals, but ordinary hook-up wire connected to the binding posts.

In my next post I will describe the problem with the power supply and how I resolved it.