I have two recent vintage Astron RS-35M units. They still use the exact
same 723-based regulator circuit that they have used for thirty years or
more, so the design hasn't changed. What **may** have changed is the
build quality. I carefully inspected both of mine right after taking
delivery. I made sure the green wire from the AC cord was securely
bonded to the chassis and checked for obvious soldering problems. I also
tied the negative output line to the chassis. They have both been
running like trains 24-7 for the last three years or so. The only
failures I've had (on both units) are the stupid internal meter lamps.
73...
Randy, W8FN
On 2/25/2019 8:36 PM, Kevin McQuiggin (SFU) wrote:
I have a ~30-year old Astron 13.8 VDC 20-amp supply that I got when it was
retired from a project at work. I used it for low current applications for a
few years, then it went to storage for about 5 years.
One of the two power transistors failed a few months ago and this took out some
other components. I had put it back into service in a 5-10 amp application. I
figure that the failure was likely just due to age and the fact that the supply
had been in storage for a few years.
I replaced both of the power transistors, two blown diodes, the electrolytics,
and a couple of ICs and other components, and the supply is running fine again.
Solid output at 10 amps load.
Given its age I am extremely happy with it. The internal quality and
components seemed good, but that may have been due to its design/manufacturing
era. Not to sound like some old codger, but perhaps designs aren’t as robust
as they used to be.
Kevin, VE7ZD
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