Do you happen to know if Astron power supplies are available with 'remote
sensing'..? I've got several Lambda power supplies that DO have remote
sensing and they keep the voltage at the load-end of the cable at 13.8 VDC,
regardless of load changes.
BTW, the Lambda's have massive crowbars also..!
73, Larry - W1GOR
----- Original Message -----
From: "WILLIAM MANSEY" <wa2pvk@msn.com>
To: <mschellur@earthlink.net>
Cc: "TenTec" <TenTec@contesting.com>
Sent: Wednesday, May 21, 2003 22:58
Subject: [TenTec] Re: Astron mod
> Hi Mike and everyone,
> The modification is to protect the regulator from excessive current,
in
> the current limiter circuitry, due to the presence of the battery. I
> apologize for the poor quality of the schematic on my web page. I do not
> know what caused that because it WAS clear when initially viewed on my
> computer. At any rate - the modification is simply cutting a foil on the
> circuit board between pin 4 of the 723 regulator and the wiper of the
> current limit potentiometer and soldering in a 10k 1/2 watt resistor
across
> the cut.
> As far as Astron reliability is concerned - - - I have 2 RS-35's and a
> RS-20 which have been on 24/7 for about 4 years (aside from the occasional
> power failure OR when I turned one, or more, off briefly to do some wiring
> changes) I have had no failures or even hints of failures with these. I
> have experienced failures of power supplies (with 723 regulators) and in
> each case the failure resulted in loss of drive and ZERO output voltage.
I
> never had one run wide open due to a regulator failure. A shorted pass
> transistor WILL, however, cause such a failure. BE sure to use a power
> supply that has a "crowbar' circuit OR build such a circuit yourself!
> By the way; One of my Astron 35 amp supplies has front panel voltage
and
> current adjustment. I set that to 13.8 volts at the battery. The other
> Astron 35 amp supply is not adjustable BUT I just checked the voltage
across
> its battery and it is also exactly 13.8 volts. I hope this information
is
> helpful. 73, Bill
>
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