MICOR Discriminator Buffer Amplifier

Back to Home Motorola® MICOR® Discriminator Buffer Amplifier
By Kevin K. Custer W3KKC

This is an image of a discriminator buffer amplifier for use in a Motorola® MICOR®.

This circuit is used in the MICOR Muteboard©.

The input terminal of the buffer is connected to pin 3 of the P903 interconnect pins of a mobile or base station audio and squelch board. The output drives the repeater controller audio input.

If the add on PL filter is used, omit the 0.22 uF output capacitor, as the PL filter has an appropriate coupling capacitor.

The voltages listed near the transistor for troubleshooting were measured with a supply voltage of 9.6 volts, not 12 volts. The amplifier will run on any clean positive voltage from 9 to 16vdc, and can be used in other types of equipment.

The M9571 can be substituted with any type of silicon PNP transistor like the 2N3906 or equivalent.

This circuit was designed by Motorola® and copied from a "Railroad MICOR®" service manual.

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