On Thu, 19 Jan 2006 23:47:24 -0600, Kerry Miller
wrote:

gb wrote:
"xpyttl" wrote in message
news
Astron linear supplies use a 3 terminal regulator, usually an LM317.
These things do tend to fail from time to time. Can't tell if that's your
problem, but it is likely, and the things are cheap enough it's worth
popping a new one in to find out.



Really? What model of Astron linear power supply have you repaired or seen
that uses this design approach? I have never seen one like this -- over
past 20 years.
Confusing this with some other mfg. design?

Astron has been using the 14-pin (30 years old) LM 723 regulator IC with NPN
pass transistors (e.g. 2N3055, 2N3771) ... for as long as I have been
repairing them.

Check here for correct Astron information - repairs, etc.
http://www.kbt-dc-supplies.com/index.php

and Astron schematics (which show the LM723, not the later LM317 design)
http://www.repeater-builder.com/astr...ron-index.html

gb


I can confirm that mine has a 723, not a 317. Thanks for the web sites,
looks like some great information. I hooked up that headlight tonight
but it ran fine, pulling a bit over 3 amps for an hour or so. Maybe I
need more load to make it lose regulation.

Guess I'll start digging into that regulator board, the transistors and
all the big things like the transformer seem to be fine.

Thanks,
Kerry - WD5ABC

I would look at the radio first. Put an ameter in the 12 volt line to
the radio and see how much current it is actually drawing.

73
Gary K4FMX