Mike,
I have an Omni V and don't use a Ten-Tec PS (Mine is
an Astron 35A), but I ran across something with it
that might be of help to you.
I noticed for a time that the heat sink on the power
supply seemed to get warmer than I remembered (with no
load). I thought it might just be me or aging of the
some of the parts (it's about 11 years old).
I bought an Omni V a few months ago and was checking
the BFO frequencies and the output frequency with a
counter and noticed a frequency change of 200-500 hz
from low to high power. I checked the voltage at the
transceiver and found that it was dropping about 2
volts at high power. I checked the DC cable, circuit
breaker, connectors, etc. Everything seemed ok, so I
opened the power supply. I checked all the connections
and tightened the 'mechanical' connections (The large
electrolytic in this supply is attached to the
regulator board with screws and these also serve as
the electrical contact points for the cap.) I checked
again and the problem was still there. I had an
earlier model of this power supply that had a high
current full-wave bridge rectifier, but this one uses
2 stud-mount rectifiers in a full-wave tap
configuration. I checked these guys, and one of them
was so loose I could unscrew the nut on the bottom by
hand! The common connection to the rectifiers is held
in place by these mounts, which also hold the
rectifiers to the bottom of the power supplytightened
I thightened both of them like they should be,
readjusted the regulator voltage control for the
proper voltage output and everything worked fine.
With no load, the heat sink is barely warm now. I
think what was happening is that instead of being a
full-wave circuit, with one rectifier very loose, it
was acting as a half wave circuit. Without load, the
voltage output is higher in a half wave configuration
(about 1.4 * the AC voltage applied if I remember
correctly), but under load it drops to .9 or so. I
believe that's why the heat sink was much warmer
because the transistors were having to deal with
higher voltage. But under load, regulation went shuge
because of the hugh voltage change at the regulator.
Even though I didn't measure output power, I'm sure
there were issues there as well, with the supply
acting like this.
You might want to take a close look at your power
supply.
Anthony, NT4X
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