jchoevel@ihlpg.UUCP (hoevelaken) (03/19/85)
Fellow c64 users,
I promised last week to give details about upgrading
the c64 with a reset button.
First you should have a copy of the c64 reference manual.
Unfold the circuit diagram that goes with this manual.
Look up the spot where R50 and C105 are hooked up to the
trig input of U20.
Open the case of the c64.
Try to find this spot on the circuit board. (it is real
easy because the components are numbered on the circuit
board aswel.)
Solder a wire at this point.
Cut the wire that is connected to the 5-pole DIN plug CN5
that is called AUD IN (you can select any other but this
one is not in use by most of you I guess)
Solder the other end of the wire to this point.
Now you can use one of the spare wires of the monitor
connection cable that has a connection with this inlet for
your reset button. e.g. built in the reset button in your monitor.
When you short circuit the former AUD IN inlet to ground
it resets the c64. _______ -----
____ | |-RESET
+5V ---|____|----|-----|-----|trig |
R50 | | |U20
--- | |
___ | ------
|C105 | /reset button
__|__ --------------/ ----|
___ __|__
_ ___
_
You will notice that not for all bought software the
c64 comes into the initial state when the reset button
is used.
That is because they put their own initialization routine
in place of the kernel routine.
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be aware that this surgery voids your warranty.
I don' t take any responsibility for damages that
may occur.
******************************************************
Good luck!
ihlpg!jchoevel