Well, I finally got access to a scanner, so here it is.
This is the instructions and schematic for a garage door hacker.
It modifies an existing door opener to run through every possible code.


All of this information is taken without permission from
Cybertek: The Cyberpunk Technical Journal, Issue #5.
Published by OCL/Magnitude, PO Box 64, Brewster, NY 10509.
Subscriptions $15/year.
(I have no idea if it's still published, I let my subscription
expire a year ago.  However for a similar publication contact
vortex@cats.ucsc.edu )

From Cybertek:

[The opener] uses a 555 timer as a pulse generator to transmit pulses
to a binary counter.  Each pulse will increment the binary counter
by one.  You can adjust the speed of the counting by turning
R1.  Go ahead and experiment to find just the right speed to
use.  Switch one is for resetting the count back to the beginning.

As you may notice, the schematics don't show how to connect directly
to the garage door opener.  What I do is this: First you must desolder
the DIP switches from the door opener and solder an IC socket into
where the DIP switches were.  (This will allow you to put the DIP
switches back, when operating in normal mode.)  Second, you should
connect the output to a wirewrap IC socket.  If you mount the IC socket
on your pc or perfboard you can use the socket to plug right in to
the door opener.  When connecting the output, be sure that the connections
on the wirewrap socket correspond to the ON setting of the DIP switches.

Parts List
----------
Resistors
   R1 - PC mount 100k potentiometer
   R2 - 1k ohm 1/4 watt
Capacitors
   C1 - 22MFD
Integrated Circuits
   IC1 - 555CP Timer
   IC2 - CD4040BE 12 stage binary counter
Misc
   LED1 - 10 Light Emitting Diodes
   S1 - Normally Closed Momentary Push Button Switch
   Perfboard
   9V Battery


--------------------------------------------------------------------------
----
Here are some additional assembly hints I came up with during construction
of this project.  The original instructions were a bit vague and maybe
this extra stuff will help a little.
                                            -Ryan

    You should have 12 leads coming from the circut when it is completed -
10
from the binary counter and 2 for power, + and - .  The 10 from the
counter
should go where the DIP switch was; there will be an empty socket where
it was removed (obviously).  One row of holes will be shorted together and
go to ground, and in the other row each hole will connect individually to
a pin of a nearby IC chip.  Connect the 10 leads from your circut to the
holes that go to the IC chip, not the ones that are shorted together. 
That
leaves the positive and ground leads from your circut still hanging
around,
just connect them to an external 9v battery or the one already used by
the door opener.  When connecting the positive lead to the battery, insert
a 65 ohm resistor (R3 - not shown in schematic or on parts list) in series
between the two - this cuts the operating voltage to about 6v, reducing
the
operating temperature and prolonging the life of the circut.
    The most important modification of the original plans is to substitute
a 20k ohm potentiometer for R1 instead of using a 100k ohm.  This gives
much better control over the speed at wich the circut cycles through
codes.
    Also, in place of using 10 individual LEDs in the circut, Radio
Shack's
got a nice little 10-segment LED bargraph display that makes things look
a lot neater (cat. 276-081)