AVR-Chat

Since this is "Mk I" and won't be subject to vibration I think I'll skip the
glue.  But on "Mk II" I'll use some epoxy.   Thanks for the tip.  Steve

 

From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of George
Sent: Wednesday, December 31, 2008 1:25 AM
To: AVR-Chat@yahoogroups.com
Subject: [AVR-Chat] Re: crystal mounting

 

--- In AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com> ,
"Steven Hodge" <stevehodge@...> wrote:
> am I supposed to solder the can to the big pad under it also?

I dont know the particulay crystal but most 32k watch xtals are in a 
tiny cylindrical metal case. If it is one like that then do not 
attempt to solder it. It may be aluminium anyway which will be next to 
impossible to solder. The heat will likely damage the crystal. The big 
pad is probably to stop you putting any other pcb tracks under the can 
which would short circuit them.
My suggestion is to use a blob of light glue (e.g. somthing out of a 
tube for general purpose office/home use) to hold the body to the pad 
to prevent mechanical vibration. Don't use anything like bathroom 
sealant which is nice and rubbery but contains an acid which could 
cause damage.
USe something you can peel off with a knife when you want to re-use 
the crystal for the Mk II pcb...

luck,



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