14 Aug
2010
14 Aug
'10
1:26 p.m.
On Fri, 13 Aug 2010 19:31:09 +0100 (BST)
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
I would be suporised if it wasn't, but then I am often suprised
I asusme it's a norm,al 32768Jz one.
Maybe. I don't know. How are the connections fro the battey and
crystal made to the chip itelf?
The chip (wide 24 pin DIP) has pins on the short
edges. Two between
pins 1 and 24 for the XTAL, two between pins 12 and 13 for the battery.
These special pins don't come out of the chip. They go up into the top
close to the edge. The top is a plasic cap filled with resin. (The chip is turned top-down to pour the resin into the cap.)
There is a small
gap between the top and the actual chip in the middle of the divice.
Only at the edges, where the wires go upward, are covered with resin.
So the top is fixed to the chip mostly by the four wires and a bit of
resin that coveres the wires at the short edges.
That is why I don't like to remove the battery by cutting the top in
half. The XTAL part of the top will only be fixed by two wires and a
litle bit of resin. To make it machanicaly stable again you would have
to glue the dangling XTAL half to the chip again. But why do that extra
Right. Doesn't sound impossible ot make this stronger, though.
work and fight with messy glue if you can avoid all of
this just by
carefull and not so intrusive surgery?
I am always worried about leaving dead battereis in things. I still
believe leakage could be a problem, and I'd rather I didn't get
electrolyte all over the PCB, for example.
-tony