[Amps] 374A will not turn on ??? Suggestions?

[Ron Youvan]

chas  k5dam wrote:

> Lou
> what causes the resistor(s) to go bad?  is it the surging like turning on and
> off an incandescent light bulb?  iow, how often is this going to be a
> replaceable component? replace annually if used daily or twice daily?

   I'm not Lou, but only vacuums, (because of the enclosures) filaments (in vacuums) and chemicals 
in parts (mostly electrolytic capacitors now-a-days) have a life expectancies.
   (are expected to fail within a known time range, which depends mostly on quality, excluding 
outside influences)

   Everything else fails because of:
Abuse, thermal or physical
built in problems, voids, stress or impurities
environmental condition, such as water intrusion or weather  (not being protected from)
and possibly because of any organic component becoming altered by age and other effects
like the phenolic surrounding carbon composition resistors and also used in some "pots."

   Parts made from some materials tend to outlast (tolerate more abuse without changing) parts made 
from other materials:
Ceramic outlasts phenolic
Wire wound resistors outlast carbon (but is more suitable for low  Ohmage resistors)
Metal film resistors outlast carbon (but is more suitable for high Ohmage resistors)
   And both of these generally last longer and can withstand more abuse if they are sealed inside of 
a ceramic coating.
-- 
    Ron  KA4INM -    Ron  KA4INM - Did you know ...
                     ... that no-one ever reads these things?