>>> If you
>>>think that he had a parasitic event while unkeyed, please explain how
>>>this could happen. I always belived that a tube in cutoff would be very
>>>hard to get oscillating. You also told me this once.
>>>
>>? The how part beats me. It has not happened to me, however, I have
>>talked to a number of those who have had it happen. How do we know it
>>was a parasite? Bent fil. helix / sudden change in suppressor resistance
>>/ 6kV bandswitch arcs in amp. with 3kV anode supply, are clues.
>
>I guess it happens to those who think that every bang is a parasitic
>oscillation. For one, with proper suppressor resistors you shouldn't have
>an oscillation.
? The Challenger o-rings were supposed to be plenty ok in cold weather.
>I don't think the oscillation changes the value of the
>resistors.
? A big-bang event happens in a 2-holer.. The suppressor resistors are
100 ohm +/- 5% units. The resistors appear to be in mint condition. .
Each resistor is virtually shorted by a few turns of #16 copper wire.
The measured resistance of the suppressor resistors was over 400 ohms.
I was there. I made the measurements.
>Rather, I think the resistor values change over time and over
>being heated up. Then you can get an oscillation because of bad resistors
>and hence a suppressor not performing properly.
>
>But the only thing that blew in this guy's amp was a resistor. Don't
>think he had the beloved parasite.
>
? If he has a bent fil. helix, my guess is that either he has been using
the amp. in an aerobatic aeroplane, or he had an intermittent parasitic
oscillation.
- later, Jon
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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