slighty OT: How long do relays last ?

[Michael Buchstaller]

Hello Group,

i recently discovered a pile of relays that i have acquired ca. 1985. They have
been in my basement since then and look fine since they have been in their
original carton since then.

In the last months i began using some of them in DIY projects (OK, not for a synth,
but for controlling my garage opener motor and for an automated PC controlled
capacitor matching device).
Surprisingly, approx. 9 out of 10 of the relays do work just fine, the others seem to
hang trom tome to time (when i knock them with a screwdriver, they keep on going for
some time befor hanging agein)

Could it be possible that relays (as mechanical parts) have some grease drying up
over time even when they were not used ? The relays are hermetically sealed ones
fom Zettler (AZ 693-055-2) and i have gotten them directly from the factory, so they are
not untested surplus units.

Any hints ? Do relays have a mechanically finite lifespan ? (not the max. number of
on/off cycles or contact wear)


-Michael Buchstaller