Note
The HWA-2026-3 power supply was designed for the HW-2036(A), and appears outwardly identical to the HWA-202-3. At first glance, even the insides look the same, but a closer examination of the circuit reveals differences that set them apart electronically.
The differences are small—a bit more current handling capacity (2.7 amps compared to 2.2 amps) and better voltage regulation (1% no load to full load, as opposed to 1.5%). The duty cycle (40%) remains unchanged.
The improvements are due to better filtering, a bigger pass transistor, and a more sophisticated voltage regulator integrated circuit.
Note that the output is protected by a fuse on the rear panel. (This is a step back from the HWA-202-1, where the output was electronically protected). There is a fuse inside the cabinet for the 120 VAC side.
References:
Crowbar circuit for. Ham Radio, Nov 1978, p. 88.
Output voltage: 13.8 VDC regulated, adjustable from 12.5 to 14.5 VDC
Output current: 2.7 amps with a 40% duty cycle
Regulation: better than 1% from no load to full load
Ripple: less than 0.1%
Power requirements: 120/240 VAC, 50/60 Hz, 75 watts maximum
Size: 3 high x 7.25 wide x 10 deep; Weight: 5 lbs
Solid State
diodes: (1) 1N2071, (4) S-5A05
transistors: (1) 2N3055, (1) MPSU05
integrated circuit: UA78MGT4C
Photos, general information and specifications from "Heathkit: A Guide to the Amateur Radio Products," by Chuck Penson, WA7ZZE. Used with permission.
