Changing the clock frequency slightly (PDP-11)?

[J.C. Wren]

    You can order oscillators programmed with custom frequencies from 
DigiKey, assuming you're speaking of oscillators and not a crystal (I 
have someone at work who routinely interchanges the terms, and it drives 
me up the wall).  They may not be in metal cans, but they are available 
in the same foot print.  DigiKey can have them to you as fast as you 
want to pay for shipping.

    --jc

Charles wrote:

>After pulling out my hair for a while trying to get my PDP-11 to
>talk to me, I finally discovered that the master clock (26.667 MHz
>crystal oscillator) is dead. (KDF-11BA CPU board).
>
>Those metal-package oscillators are very common and inexpensive
>(around $2), but I can't find one in that exact frequency. 25,
>25.175 and 27 MHz units are available. Semi-custom ones aren't
>terribly much more expensive (~ $15) but have longer lead times.
>
>Is there anything in the circuitry that can't be run a little
>slower (or 1.2% faster, 27 MHz)? I'm not worried about squeezing
>every last MIPS out of it.
>
>thanks
>Charles
>
>  
>