Trying to fix up a Casio 4379

[Harry Bloomfield]

Hi all,

I have been given a Casio 4379 watch, in great external condition, but
no so inside. The ex-owner suggested it had suffered moisture ingress,
but there was no sign of internal damage I could obviously see, but
what I did find was some rolled up tape pushed around the edge of the
movement, such that as the back was screwed down, it pressed on the
movement, a far to big gasket seal (which explains the ingress) and
rather than the CR1616 battery holder being latched down, the latch had
been flattened, so only the back cover applied pressure on the battery.
Even with the latch straightened, I could not achieve proper contact
with the battery, unless I pressed the centre of the battery metal
bracket to make contact.

Under the bracket is a soft insulated grey flat ring, where it is
supposed to make contact with the battery +ve. The ring is exactly the
same outer diameter as the battery, so I'm wondering if the ring was
designed to fit under the battery, rather than on top? I suspect who
ever last swapped the battery, might have accidentally swapped the
position.

Anyone know the type / size profile of the case rear cover seal please.
I have guesses at 32mm round profile, did I guess correctly?

[Harry Bloomfield]

Under the bracket is a soft insulated grey flat ring, where it is supposed to
make contact with the battery +ve. The ring is exactly the same outer
diameter as the battery, so I'm wondering if the ring was designed to fit
under the battery, rather than on top? I suspect who ever last swapped the
battery, might have accidentally swapped the position.

I think I have resolved that one, it works fine with the washer between
the movement and the battery.

Still not clear on the rear case seal though?

[Harry Bloomfield]

Post by Harry Bloomfield
Still not clear on the rear case seal though?

I would seem to be talking to myself here?

I ordered a pack of 100x seals in the 30 to 50mm diameter range and
none fitted :-(

The nearest was the very smallest one, too small so must have been a
30mm the rest were all in the 40 to 50mm range. The 30mm snapped in
trying to stretch it, so I tried a botch - cutting a larger one,
supergluing around the seal slot, then finally cutting to correct
length for the ends to meet. Not sure whether it managed to form a
proper seal yet, I have not tested it. I will test it later, but it
allowed me to get the job finished at last.