Power Supplies

Prototype Power Supply / Armdroid 1

The following circuit diagram is the original 12V power supply published in ETI

Model P402 (UK specification) / Armdroid 1

An original (standard production) 15v power supply - manufactured by Adman, Harrogate, Yorks for Colne Robotics Ltd.  This model is rated 220/240V ~ 50Hz input, 14.6V DC 4Amps regulated output.   Two terminal posts would be used to bind the power cord to the Armdroid's 2-pin power connector.

Looking inside...  A single (very large) transformer with rectifier bridge (KBPC602) feeds the UA78H12ASC power regulator mounted on the rear heat sink.  The reference voltage is determined by the variable 1K trimmer and fixed 1K Ohm resistors.  This circuit is also supplemented by a couple of smoothing  & filtering capacitors, including the large LCR 10,000uF 35V.  The circuit is implemented on the small tag-strip, with all other components soldered point-to-point.

This model when measured with my digital multimeter is reading 15.13 Volts.  Presumably, the voltage was increased from 12v to 15v in an attempt to prevent the motors from struggling.

Interestingly, Adman was also responsible for manufacturing a Speech Synthesizer product for the C64/VIC20 back in the early 1980s [citation needed]

Model 001-01022 (USA) / Armdroid 1000

Armdroid 1000 power supply by D&M Computing Inc.
Ratings:  Output 13.8 VDC - 9A continuous, 12A maximum
Input 115V 60Hz
Produced by ASTRON Corporation, Irvine, CA. model RS-12A

Modern Replacement

If your looking for a suitable equivalent in the UK check  my blog post Power Supply which although this switched-mode PSU is rated at 12V (which was the voltage for the original prototypes) seems to work well enough.   This post also contains details of the connector required.