Hi Kevin,
Here's my two cents regarding Astron Power
Supply regulator boards.
Most basic power supply regulator boards
using the LM723 circuit have engineering
shortcuts. Problems resulting from LM-723
regulation circuit design shortcuts often
rear their ugly head at much later dates.
I've isolated the cause of three or four
reported major supply problems directly
to the supplied regulator board.
1. Poor RF Immunity
2. Modest actual regulation and gross dc
overshoot (causing the crowbar circuit to fire)
3. Poor current limiting
4. A rude basic 723-regulator circuit,
the design of which could be much improved
I revisited the mfgrs 723 data sheet for a
better high voltage regulator (screen supply
regulator for a broadcast transmitter) circuit
and came up with the better "mouse trap" by
paying attention to the data sheet notes.
The revised regulator board has better
pre-regulation and isolation. RFI suppression
is addressed in the revised regulator circuit.
It's an exact Astron board with the newer
circuit layout, drops right in place of the
original board*.
There is an option available for (device ratings
qualified) front panel � variable dc control.
Upon initial install, the user with the regulator
board retrofit tests the crowbar circuit. Indeed
no crowbar protection (function) has ever fired
in circuits with the new board in operation. This
classic gremlin has been properly put to bed.
I have applications where power supplies simply
cannot fail. I came up with the retrofit regulator
board project to keep the sanity of some very
high-end customers and myself. I had not ever
thought about reselling them retail, but many
things are possible.
Most all of the 30 plus boards I have "out there"
have been retrofit for customers by me as a
complete supply upgrade package.
If you feel your Astron supplies are worth an
upgraded regulator board, you can drop me an
Email and I'll try to work up a practical field
replacement package for direct sale. With my
parts cost and invested time, I honestly see
the as yet un-priced package costing at least $45
(Amateur net price).
Especially since I have been setting up typical
small batch quantities of 10 lots. Commercial
customers with life safety power supply failsafe
requirements pay a considerably higher price
for the same circuit board.
Information I would need would include the
model number and the option for plain or metered
(voltage & current) power supply front panel.
*There are Astron Production revisions. Additional
details would include the number and size of
the large internal filter capacitors.
Cheers,
Skipp
www.radiowrench.com
skipp025 at yahoo.com
> Kevin Custer <[EMAIL PROTECTED]> wrote:
> I'm interested, and would prefer you to post to the list.
>
> Kevin Custer
>
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