"Bill Turner" wrote in message
...
On Fri, 10 Dec 2004 23:19:17 -0800, "Ed Price" wrote:

I don't know what you mean by the "life" of a carbon comp resistor. My
experience is that they last forever, until you kill them somehow. Drift,
under low power, hasn't been a problem for me. I have never seen 40%
drifts,
except for very abused parts, and if you are using the 2-watt carbon
comps,
you can hear or smell when you are abusing them.

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Then you just haven't been around long enough. I worked in the TV
repair industry for just under 20 years and I have replaced hundreds of
carbon comp resistors which were NOT abused in any way, but failed none
the less. It's an ancient design which time has passed by.

Yup. I just rebuilt an old Heathkit resistor substitution box, 1966 vintage,
and the resistors were absolutely wild. Some were better than double the
rated value. I don't think I saw any decrease in value. None had any obvious
sign of overheating.

Having said that, different manufacturers' resistors held up better than
others, but today, they are all doubtful. The ABs were good when they were
new, the Ohmites were OK, and the IRCs were questionable from the minute
they left the factory.