To amplify some of Bob's points, check the frequency before and after 
potting if possible to see if there is something going on.  If something 
changed in the potting technique, the potting compound could be adding 
mechanical stress to the components and maybe be pushing them towards 
out of spec operation.

If potting compounds were changed from back when it seemed everything 
used to work, look to see if the potting compound is exothermic to such 
an extent that it damages components.  I have seen that one before.

One technique sometimes used when potting is producing mechanical stress 
is to give the components a light coating of rubber like silicone RTV 
(caulk, etc.) then encapsulating the unit.

I would contact Microchip just in the event a) they know something about 
this and b) are willing to tell you.

Good luck!

Bob Blick wrote:

> 
> Hi Shawn,
> 
> I've had some experience with 32KHz problems on another chip, and there
> are a few things that come to mind that may help you diagnose the
> problem:
> 
> If you can raise the power supply voltage 1/2 volt and retest, if the
> oscillator works better then it suggests the lower impedance and higher
> gain of the oscillator driver is having some efect.
> 
> If you have no problem with units before potting it could be moisture
> being potted along with the circuit.
> 
> Using a very low load scope probe you can see if you need to offset the
> capacitance to one side of the oscillator or the other.
> 
> Scoping it quickly you can see if there's DC bias, that could suggest
> board leakage.
> 
> I have a manufacturer's document somewhere that may have some useful
> tidbits... let me look here and see if I can find it on the interwebs...
> nope, I'll have to look for a reference to it on my computer at home.
> I'll post another message tonight with a link.
> 
> Cheerful regards,
> 
> Bob
> 

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