One lead of a 10 k resistor is soldered to pin 9 of the TA7761. A 3.5 mm chassis terminal is mounted in the back of the scanner between
the headphone output and the DC connector. Beacause the distance to the discriminator IC is short, the other lead of the resistor can be soldered directly to
the chassis terminal. I have put some isolating material around that lead of the resistor.
The scanners's housing is grounded. Therefore, you don't need to connect the chassis terminal to ground separately.