If you remove the bottom of the scanner and disconnect the loudspeaker connector, the MC3359 is easily reachable.
A 10 k resistor is connected to pin 10 of the MC3359. Pin 10 is on one of the corners of the IC. The other lead of the resistor is connected to
a short piece of insulated wire, which is connected to a chassis terminal in the back of the scanner. Because of the metal back panel of the scanner, a separate ground connection of
the chassis terminal is not required.