> >my guess was a sudden overload. The event was so brief that there
> >was no damage to the outside of the resistor -- even though the
> >resistor element
> > was almost burned out.
The reflector has been down this road before.
I have found hundreds or perhaps thousands of carbon composition
resistors that behaved that way, even when used well bel0ow the
ratings in dc or low-frequency AC circuits. Many others report the
same.
That is why carbon resistors have fallen from favor in critical
applications, especially when in hot environments.
> >>>>Were these amps that were measured while exhibiting intermittent
> >>>>vhf oscillation damaged in any way by the oscillation?
> >>>
> >>>the vhf suppressor-R was typically damaged. The resistance
> >>>suddenly increased 2x - 4x.
This claim would only be valid if the resistor was measured
immediately before failure and found perfect, that there was a
confirmed VHF oscillation, and that when checked again
immediately after the value changed.
One can not use an "it was off value, so it MUST have been a VHF
parasitic" as proof of the cause of damage. Many things, including
temperature and time, cause carbon resistors to go off value.
73, Tom W8JI
w8ji@contesting.com
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