Thanks very much for the thoughtful suggestions, Mike.

I'm collecting them here, and will revisit this issue after Field Day.

Everyone has been very helpful and patient with this thread, and I truly do 
appreciate that.  I'll let everyone know the results of further testing and 
troubleshooting as I get them.

73 from Tom Behler:  Kb8TYJ
----- Original Message ----- 
From: "Mike Duke, K5XU" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, June 25, 2011 8:38 AM
Subject: Regarding Low Voltage


In some cases, the voltage drop can be enough to cause other functions
of the radio to misbehave, or to not work at all.

In my case, the push button for the voice read out became
intermittent. That was what tipped me off that I had a problem
somewhere.

Someone suggested that I check the voltage, and I hit pay dirt.

If, after cleaning the connections and fuses, you still have low
voltage at the radio, you can turn up the output of the Astron supply.
But, do this only if the 590 is the only thing connected to it, or if
everything connected to the rig runner is experiencing low voltage.

Otherwise, you may fry some other piece of equipment in the process of
correcting the problem for the 590.

I'm glad Lou thought to mention cleaning the fuses. I completely
forgot about doing that when I had my problem.

Sometimes simply reseating the flat blade fuses is sufficient to
correct the contact problem, especially for a new power cable.

The traditional round glass fuses and holders are more apt to develop
contact issues. As the surface area of the contact point diminishes
due to carbon, dust, or whatever, a resistance develops. That
resistance is what causes the voltage to drop. It can also cause an
increase in the amount of current drawn by the rig. That too can be a
factor if you are pushing a power supply nearly to its limit.



Mike Duke, K5XU
American Council of Blind Radio Amateurs