The unfiltered audio can be found on pin 9 of the MC3361 or MC3371 receiver IC.

Follow the next steps to make the discriminator output:

• Connect a 10 k resistor to pin 9 of the MC3361 or MC3371
• Connect a 2.2 nF capacitor from the resistor's other lead to ground

Make sure that the resistor and capacitor are mounted below the level of the the shielding, or the circuit board won't fit back into the radio's enclosure.

There is no need to mount an additional connector in the radio for the discriminator signal. Pin 5 of the 15 pin sub-D connector at the back of the transceiver is unused (spare). It is perfectly possible to use this pin to connect the unfiltered audio from the discriminator IC.

• Connect a piece of wire to the junction of the 10 k resistor and the 2.2 nF capacitor
• Connect the other end of this wire with pin 5 of the 15 pin sub-D connector in the back of the radio

If required, you can put a small piece of isolating tape over the resistor and capacitor, to prevent these components from inadvertedly making contact to the radio's enclosure.