DX 100 parasitic (?) problem on 10 meters

[Jon Schmidt]

Hello Gang,

I have an Apache doing almost the exact same thing, except that it does blow one of the
two fuses on the transmitter and it seems to work fine otherwise.  Good drive, works great
for a while, then it will have some run away condition (like parasitics) in which the rig
will hum loudly and blow a fuse.  I have only used it on 80m, so I don't know if my
problem is only on 80m, or if it will occur on the other bands as well.  I am anxious to
fix this problem, so now there are at least two of us who could use some help!

Thanks and 73!

Jon  WD8JSA
San Clemente, CA

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Huttinger wrote:

> Hi,
>     I acquired a DX 100 with problems a few years ago.  My DX 100 works okay
> now on the band I use it on (160) though the output has gradually fallen off
> to around 60 watts for no apparent reason.  I have plenty of drive on all
> bands and the finals check good on an emission type tube tester.  I also
> have a problem on 10M though different from Glen's.  If I try to crank up
> the drive at all above zero mA I get a loud hum from the power supply and
> the house 15 Amp circuit breaker throws indicating a huge current draw.  The
> puzzling part is why don't the fuses in the DX 100 blow?  I think I am
> getting a parasitic oscillation though  that theory doesn't seem right since
> I don't get an abnormal plate current reading when the overload occurs.  My
> only guess is I may have another capacitor in the output stage somewhere
> that is bad.   Any hints or clues on what may be happening would be
> appreciated.  I would take crystal ball information as well!
> Mike

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