Astron does have some funny circuits.
I think it is the 35 amp supply that uses half of a bridge for a full
wave rectifier, instead of a bridge. In some other models maybe they do
use a bridge as a bridge.
The RF sensitivity has not been observed on a couple of 35 Amp Astrons
at Red Cross here. These are on HF and VHF rigs.
Likely the mod that fixes things is a 0.01mf disk ceramic cap across the
DC leads just inside the output terminal bolts.
The other point that should have a cap is the 3 terminal regulator.
Look up data sheet sample circuits for the LM 317.
Some have reported the outer case joints not making good electrical
contact, and removal of paint where they overlap helps.
Tightening all bolt connections especially; if the supply is moved
around for Field Day, or portable uses, is a good thing to do from time
to time.
Stuart Rohre
K5KVH
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