[Elecraft] Linear PS Recommendations

[John Oppenheimer]

Hi All,

Here is a link to a schematic for the 3/4 A power supplies with the
added parts for external voltage protection:

http://www.ameradio.com/doc/Astron%20RS-3A,%20RS-4A%20schematic.pdf

John KN5L

On 07/21/2016 07:41 AM, Myron Schaffer wrote:
> It used to be that way....the RS linear models could not tolerate external voltage present when unpowered, not anymore. Astron has incorporated back-voltage protection through incorporation of some diodes installed in key locations to prevent this.
> 
> You can verify if your supply has this modification by looking at the circuit board and see a 1N4001 type diode soldered across 2-pins (can't remember which ones off the top of my head) of the IC voltage regulator LM-723 chip and others hung in various places to protect the pass transistor as well. Usually soldered to the solder side of the circuit board so they are easy to spot. I can't remember is there were some small capacitors added as well.