This series consist of schematics, mechanical drawings, notes, test program printouts, and proposals created by Ron Kocol throughout his Test Engineering career. The materials are for a power supply H.V., video power pack, coin slots, Pinball 2000, PC based cable, coin hopper, and an 8 pair OPTO. Of note are the two engineering notebooks maintained by Kocol. The notebooks contain information about analog and optical joysticks. The bulk of the materials are dated from 1984 to 1986.