Motorola Cdm And Pro Series Detailed 68p81091c63 O Manual

1-1
Chapter 1
Introduction
1.1 Scope of Manual
This manual is intended for use by service technicians familiar with similar types of equipment. It 
contains service information required for the equipment described and is current as of the printing 
date. Changes that occur after the printing date are incorporated by a complete manual revision or 
alternatively, as additions.
1.2 Warranty and Service Support
Motorola offers long term suppor t for its products. This support includes full exchange and/or...

1-2Related Documents
1.3 Related Documents
The following documents are directly related to the use and maintainability of this product.
1.4 Technical Support
Technical suppor t is available to assist the dealer/distributor and self-maintained customers in 
resolving any malfunction which may be encountered. Initial contact should be by telephone to 
customer resources wherever possible. When contacting Motorola technical suppor t, be prepared to 
provide the product model number and the unit’s serial...

Warranty and Repairs1-3
Par ts Order  Entr y
7:00 A. M. to 7:00 P. M. (Central Standard Time)
Monday through Friday (Chicago, U. S. A.)
To Order Parts in the United States of America:
1-800-422-4210, or 847-538-8023
1-800-826-1913, or 410-712-6200 (U. S. Federal 
Government)
TELEX: 280127
FAX: 1-847-538-8198
FAX: 1-410-712-4991 (U. S. Federal Government)
(U. S. A.) after hours or weekends:
1-800-925-4357To Order Parts in Latin America and the Car-
ibbean:
1-847-538-8023
Motorola Parts
Accessories and...

1-4Radio Model Chart and Specifications
1.6 Radio Model Chart and Specifications
The radio model charts and specifications are located in the Basic Service Manual listed under the 
Related Documents paragraph of this chapter.
1.7 Radio Model Information
The model number and serial number are located on a label attached to the back of your radio. You 
can determine the RF output power, frequency band, protocols, and physical packages from these 
numbers. The example below shows one portable radio model...

2-1
Chapter 2
Theory of Operation
2.1 Overview
This chapter provides a detailed theory of operation for the radio and its components. The radio is 
designed as a single board unit consisting of a transmitter, receiver, and controller circuits. The board 
also accepts one additional option board that can provide functions such as secure voice/data, voice 
storage, or a signalling decoder.
A control head mounted directly on the front of the radio or remotely connected by an extension 
cable provides a user...

2-2Theory of Operation
2.2.1 Radio Power Distribution
The dc power distribution throughout the radio board is shown in Figure 2-2. Voltage regulation for 
the controller is provided by four separate devices:
nU0651 (MC78M05) +5 volts
nU0641 (LM2941) +9.3 volts
nU0611 (LM2941) +12 volts
nVSTBY 5V (a combination of R0621 and VR0621)
nAdditional 5 volt regulator located in the RF section.
The dc voltage applied to connector J0601 supplies power directly to the following:
nElectronic on/off control
nRF power...

Theory of Operation2-3
Figure 2-2.   DC Power Distribution Block Diagram
The INT SW B+ voltage from switching transistor Q0661 provides power to the circuit controlling the 
audio PA output. The voltage is monitored by the µP through voltage divider R0671/R0672 and the 
line battery voltage. Diode VR0671 limits the divided voltage to 5.6 volts to protect the µP.
Regulator U0611 generates the voltage for the switched supply voltage output (SWB+) at accessory 
connector J0501, pin 13. U0611 operates as a...

2-4Theory of Operation
2.2.3 Emergency
The emergency switch (J0501, pin 9), when engaged, grounds the base of Q0662 via the 
EMERGENCY CONTROL line. This switches Q0662 off and resistor R0662 pulls the collector of 
Q0662 and the base of Q0663 to levels above two volts. Transistor Q0663 then switches on and pulls 
the collector of the npn transistor within Q0661 to ground level This enables the voltage regulators 
via Q0641. When the emergency switch is released, R0541 pulls the base of Q0662 up to 0.6...

Theory of Operation2-5
2.2.6 Microprocessor Clock Synthesizer
The clock source for the µP system is generated by the ASFIC CMP (U0221). Upon power-up the 
synthesizer IC (FRAC-N) generates a 16.8 MHz waveform that is routed from the RF section to the 
ASFIC CMP, pin 34. For the main board controller the ASFIC CMP uses 16.8 MHz as a reference 
input clock signal for its internal synthesizer. The ASFIC CMP, in addition to the audio circuit, has a 
programmable synthesizer which can generate a synthesized...

2-6Theory of Operation
The option board interfaces are different in that the µP can also read data back from devices 
connected.The timing and operation of this interface is specific to the option connected, but the 
general pattern is as follows: 
nOption board generates a service request via J0551, pin 29, line RDY, and µP, pin 79
nThe main board asser ts a chip select for that option board via U0141,pin 14, line OPT CS, 
J0551,pin 30
nThe main board µP generates the CLK (J0551, pin 3)
nThe main board...