[TenTec] Astron SS30 power supply leave on?
rohre at arlut.utexas.edu
Wed Jun 24 19:52:14 EDT 2015
All Astron supplies I, or my club have owned have had terrible quality
control and really off the wall circuitry. I have had them act as
lightning sinks on more than one occasion, either at the club station or
at a friend ham's home. The off the wall circuit was using a bridge
rectifier as a full wave rectifier, ie using two of the four diodes only.
I unplug my power supplies when the station is not in use. Comes from
living overseas in intense thunderstorm, jungle areas. I have seen
appliances hit twice in two years, on the same outlet!
The Astron series pass regulator chip is the first thing to fail, as if
it was designed as a lightning fuse. I have diagnosed many Astron
failures by simply asking "was this supply plugged into power and on
during the recent storm"? The linear regulator IC is the first thing I
bring out of the spare parts bin, if the answer is positive.
One of our club's failed Astrons was still emitting smoke from failed
components on Monday noon after a weekend storm. That one was plugged
into the AC line but turned off. The surge arced through the switch.
The quality of wiring and soldering is often suspect. Wires poked well
past terminal points with excess wire out in space. Questionable solder
I always check an Astron with a good DC voltmeter to make sure it is
putting out a regulated voltage. Another component known to fail are
any MOVs included across the AC line connections. Those have been known
to fail to the point of combustion.
I would never leave a power supply on 24/7 as the risk of fire in it is
all too real. For a little while, an out of control DC supply can push
some serious voltage and currents. I have seen it happen.
Nothing about an Astron says industrial grade to me. In fact, in TX,
repeater owners will not put an Astron supply into a remote repeater
site because of bad service histories with them.
As always you get what you pay for. They are lower priced, but serve
satisfactorily if you are able to repair them and access them easily.
We have seen the parallel transistor schemes they use on the higher
rated supplies fail by not sharing the current equally among the
parallel power transistors. You have to match the transistors to each
other to have such a scheme. The emitter resistors usually blow, one by
one, as the remaining transistors try to share the demand for current.
I even bought another brand of power supply that had built in voltage
metering, to give a quick check that I did have the voltage desired for
my main rig.
I don't mean to be too harsh, but hard earned experience makes me more
cautions of power sources now.
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