Back to Home   Motorola® MICOR® Discriminator Buffer Amplifier
By Kevin K. Custer  W3KKC
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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 basestation audio and squelch board. The output drives the repeater controller controller audio input.

If the add on PL filter is used, omit the .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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Page created by Kevin K. Custer  W3KKC   12-30-1996
Article text, artistic layout and hand-coded HTML © Copyright 1996 and date of last update by repeater-builder.com.

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.