"Kerry Miller" wrote in message
news:CNEzf.140599$WH.64582@dukeread01...
I've got a problem with my Astron RS-20 power supply. With no load, it's
fine, but anything above 4amps or so makes it drop way down and my rig
drops out of lock. I haven't measured it under load but the rig works ok
to 10 or 11 volts so it must be dropping below that.

I found a schematic and downloaded it, all the voltages are fairly close
to what it says on the schematic with no load, I haven't made any
measurements with a load on it. I'll pick up a headlight tomorrow to put
a load on it and make more measurements.

Does anybody have any ideas?

Thanks,
Kerry, WD5ABC

Kerry -

From you description, you have lost REGULATION .

Read the KBT web site for ALL required diagnosis and repair steps for linear
power supplies and Astron. MENU BAR is GRAY LIST ON LEFT
http://www.kbt-dc-supplies.com/index.php

Replace LM723 regulator chip ...
TEST PASS TRANSISTORS (2N3055 or 2N3771)

How it Works - David Metz's classic article - now 10 years old
http://www.seits.org/features/pwrsup.htm

Index & schematics for Astron power supplies
http://www.repeater-builder.com/astr...ron-index.html

gb