Motorola PM1200, Basic Service Manual

Page: 32 / 138

October 26, 2007 6880309U09-A
3-2 Basic Theory of Operation : Controller Section
3.3 Controller Section
3.3.1 Introduction
The PM1200 transceiver is primarily a dwi-board design, RF sections and power amplifier sections.
The controller section will be discussed here in basic terms, to assist in the overall understanding of
what is contained in the controller section, and a simplified purpose of its elemental parts. Some
limited warnings and recommendations are offered to prevent common repair-induced damage.
The controller section is divided into two parts:
• Control head (the "Panel Interface Unit" and the "Display Unit ").
• RF Deck.
NOTE: A control head is necessary for the function of the radio, and controller section is critical for
the RF sections to function. This is an important point since repairs and troubleshooting of the
RF sections usually require that the controller section be operating correctly.
3.3.2 Surrounding Controller Region
3.3.2.1 Introduction
The surrounding controller region contains the regulated power, audio and data translation
hardware.
This hardware allows a computer to program the radio's features, maintain an active control of the
RF sections, and make necessary mode and audio adjustments as related to feedback from a
control head device.
3.3.2.2 Voltage Regulation
The uniboard contains the following voltage regulators: 9 V, 5 V and 13.6V.
The radio's A+ supply is regulated down to additional supplies for various blocks (frequency
generation unit (FGU), receiver, transmitter power amplifier, and controller). Specifically, A+ is used
to regulate three separate 9-volt supplies: one for the FGU and receiver circuitry, one for the
transmitter power amplifier circuitry, and one for the controller sections.
3.3.2.3 Emergency
Circuitry exists to support emergency footswitch operation. If the proper features are enabled in the
codeplug using the customer programming software (CPS), then depressing the emergency
footswitch will enables alert dispatch. A button on the control head can also be programmed using
CPS to activate emergency when the radio is on. The emergency button on the control head will not
turn the radio on.
NOTE: This feature is either visual or can be set to covert, and is programmable through the CPS.
This functionality is dependent on the CPS version and customer demand for feature
availability.