For those wishing to use a Hercules II with their Jupiter.
A call to Gary, the Herc II guru, at Ten-Tec solved the issue I had with the
Jupiter not keying the Herc II. It turns out that it is an issue known to
Gary and it has an easy solution.
A Jupiter will not key a Hercules II in QSK without a simple modification.
The Herc II was designed when protection circuitry for grid block keying
amplifiers needed to be built into the amp.
As such there is a diode (D-11 located on the left bottom of the board under
D-1) on the control board (middle under top cover) for that purpose.
This diode apparently induces a voltage drop that is "just enough" to
prevent the "Key Out" line from going to ground properly when the Herc II is
hooked to the Jupiter. The fix is to jumper across the diode with a wire or
resistor. The fix doesn't affect anything else and there is nothing to
adjust. This restores proper action to the "Key Out" line and enables full
operation of the Jupiter with the Hercules II.
Whew.... glad that's fixed. Nothing was "wrong" with the amp or the Jupiter
! Just needed a bit of "updating". Can't wait to get the soldering iron
out tonight... too bad my 4 hours of troubleshooting the amp last night
didn't bring this to light <grin>... but I can say that everything else in
the amp is ok ... hehehe.
73 de Mike, W9WIS
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