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Motorola Pageboy II

Motorola Pageboy II

The Motorola Pageboy II used to be very popular with fire brigades as an alarm receiver. The pager was activated by a 5-tone code, after which a voice message was broadcasted.

By equipping the Pageboy with the right crystal, it can be tuned to your local paging frequency (146-174 MHz).

Motorola Pageboy II



IF Detector

According to the service documentation of the Pageboy II, the demodulated and unfiltered audio can be found at pin 3 of A4, the IF Detector. A4 is a prehistoric IC, with discrete components mounted on a ceramic board and covered with a paint coating.

Pin 3 of the A4 contains the unfiltered audio



IF-detector

PCB

A4 contains the FM detector

At two spots, a connection to pin 3 can be made

A resistor can be connected to one of the points indicated. The Pageboy's 2.5 mm chassis terminal, originally meant to connect an earphone, can be rewired to connect the discriminator output to the outside world.

After fitting a crystal for a Flex paging frequency and realigning the Pageboy, the oscilloscope confirmed that the discriminator output contains a neat unfiltered data signal.




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