In the trouble shooting section it says if the input SWR is high, the
input board is loose, meaning its lost some or all of its grounds. Seems
to me that's always a good thing to check, then there's only one bit of
reactive parts, the low pass filter which has probably been changed for
one passing 10 meters and a high SWR on one band hints at something
wrong in that filter.
According to vintage tube amplifier design articles from QST in the 60s
republished in the vintage ARRL SSB books, the cathode tuned circuit
does more than match impedance, it also helps the linearity that the
resistive network in the 411 won't accomplish. Else it depends on the
low pass filters in the driver to provide that low Q resonance as part
of the PA tube circuit.
73, Jerry, K0CQ
On 5/27/2010 2:33 PM, Kris Merschrod wrote:
Thank you Jerry and also Gary for the copy of the manual.
Looking at the boards in the manual it seems straight forward to find
the board. Finding the "problem" unless there is a nicely burned out
gizmo, will be a challenge.
Kris KM2KM
Merschrod
123 Warren Road
Ithaca, NY 14850
www.merschrod.net
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