I'm experiencing about a 3% failure rate on my PIC-based product.  Except 
for one time that a wire was cut, the rest of the time it's been the 20MHz 
crystal that's died.  I'm using a 16C58B chip and the crystal is an Abracon 
ABL-20.000MHZ-B2.  Is this a normal failure rate for this type of crystal? 
Also, I'm not sure what the two capacitors should be.  Right now, I'm using 
33pF capacitors with the crystal, but from what I read in the PIC manual 
that may not be right.  The PIC manual recommends 15pF, but there's a note 
that it should be 30pF if VDD > 4.5 (I'm using a 78L05 so VDD is 5 volts), 
and Abracon lists "Shunt capacitance" for this crystal at 7pF & "Load 
Capacitance" at 18pF.  Being almost totally ignorant of circuit design, I'm 
not sure what the right capacitors are, so I'm blindly using what someone 
else told me to use, but could using a capacitor that's too big cause these 
failures?

Thanks
-Mark

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist