Electro-Controls typically used 56-pin rectangular Elco connectors with pretty substantial locking screws for their control cables, but they inserted only the number of gold-plated contacts necessary for the desired functionality (up to 12 in this case). The EC standard analog control
voltage was 15.6 volts. I actually have a copy of the operation and very thorough maintenance
manual for the Playmate (I know, what a surprise!). The control cables provide operating voltages to the
console from a beefy
power supply in the
dimmer pack as well as
return the 15.6 volt control signals from the
console to the dimmers. Usually the only thing to go south are the slide pots or less frequently the
dimmer firing cards. Each Playmate
dimmer pack contained six 2400 or 3600
watt dimmer modules. Each module had the PC-171 firing card,
TRIAC, and
choke mounted on a U-shaped aluminum chassis and was self-contained, requiring only 120vac input and 15.6vdc control signal.
In later years, EC came out with a Playmate product that was their answer to the
Strand CD-80
portable packs (picture below). It used their proprietary ECmux digital
protocol and was apparently popular enough for Johnson Systems to offer a retrofit control card to update the electronics and adapt to
DMX like they do for the CD-80.
Probably a lot more than you really wanted to know.
