Greg Mayman wrote in a message to Roy J. Tellason:

 RJT> I never could figure out why the C64 had that key on it.  :-)

 GM> I must look at my mates C64 to see which key you mean...

The one with the pound symbol on it...

 GM> I have been cleaning out my shed and stripping down a pile of
 GM> non-working computers. A lot of the early ones had little
 GM> metal cased units, about 3/4" x 7/16", that I suspect are
 GM> crystal oscillators. Most of these are made by FOX, and one
 GM> typical one is labelled
 GM>  F1145 8712
 GM>  14.318180 MHZ
 GM>  FOX JAPAN

 GM> There is indeed one not made by FOX, labelled
 GM>   SARONIX 87M
 GM>   XTAL OSC 15
 GM>   48.0000MHZ
 GM>    NTC070C
 GM> I guess that is pretty definite.

 GM> They all have four pins, one near each corner, and I suppose they
 GM> operate from the 5v rail. Since they are still on the board, I
 GM> should be able to identify the +5v and 0v pins. One of the other
 GM> pins would be the output, but the fourth one could be almost
 GM> anything.

 GM> Does anyone in this echo know anything about these units?

I have a bunch of those around as well.  I don't remember which pin is the
output,  and I don't think the other pin is connected.  But yeah,  they run
off the +5v supply.  In a conversation recently with somebody they mention
that these draw a bit more power than using a crystal directly,  which he
considered to be a disadvantage in some applications.

Those modules are pretty common,  I think when the video card in this box
started flaking out on me I put a different one in there that has at least
3 of them on it.  Made my reception on the little tv that's in here get
significantly worse.

That 14.311318 MHz figure is pretty common.  It was used in the c64,  and
also in the original IBM PC/XT class machines -- that's where that
"4.77 MHz" came from,  dividing it by 3.  Divide it by 4 and you
get the 3.58 MHz colorburst frequency.  I have no oscillator modules for
that frequency but have a whole bunch of crystals... 

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