Roger said:

>We have been experiencing some high failure rates with resonators and
>the
>16C57.  We are using 3 different manufacturer's and have experienced
>failure rates in the order of 2.5 to 10 %.  Some of these are
>intermittant.  Someone had mentioned to me that this issue came up in
>the past
>on this list.
>
>Any ideas?
>
Roger:

We have recently had some resonator problems which appear to be due to
moisture penetration of the case during post-soldering cleanup. It can seem
to be intermittent. Also, make sure that your PC boards are CLEAN. Flux
residue trapped under a crystal or resonator can also cause problems which,
again, can appear to be intermittent depending on the humidity. On a board
that works OK, breathe heavily on the area that has the resonator. If it
quits, that's a clue. On a board that doesn't work due to a suspected
resonator problem, use a heat gun to heat up the resonator. If it starts
working, maybe you've got moisture problems. If it's interior, it may stop
working again after a day or so.

Hope this is helpful,
Reg Neale