Motorola Radio Mcs2000 Vol 2g 68p81080c48 O Manual

							 
68P81080C48-O,  Issued 12/98 
MCS 2000 Mobile Radio
Service Instructions
Volume 2g
VHF Frequency Range, 25W Specific 
Ó  
 1998 by Motorola, Inc., Radio Network Solutions Group 
8000 West Sunrise Boulevard
Ft. Lauderdale, FL 33322
All rights reserved.   
						

							 
Safety 0 
                Safety Information 
Every radio, when transmitting, radiates energy into the atmosphere which 
may, under certain conditions, cause the generation of a spark.
All users of vehicles fitted with radios should be aware of the following 
warnings:
Do not operate radio near ßammable liquids or in the vicinity of explosive 
devices.
To ensure personal safety, please observe the following simple rules:  
Check  
 the laws and regulations on the use of two-way mobile radios in the 
areas where you drive. Always obey them. Also, when using  your radio while 
driving, please:  
¥  
Give full attention to driving,  
¥  
Use hands-free operation, if available and  
¥  
Pull off the road and park before making or answering a call if driving 
conditions so require. 
Airbag 
Warning 
Installation of vehicle communication equipment should be performed by a 
professional installer/technician qualified in the requirements for such 
installations. 
An air bagÕs size, shape and deployment area can vary by vehicle make, model 
and front compartment configuration (e.g., bench seat vs. bucket seats). 
Contact the vehicle manufacturerÕs corporate headquarters, if necessary, for 
specific air bag information for the vehicle make, model and front 
compartment configuration involved in your communication equipment 
installation. 
LP Gas 
Warning 
It is mandatory that radios installed in vehicles fuelled by liquefied petroleum 
gas conform to the National Fire Protection Association standard NFPA 58, 
which applies to vehicles with a liquid propane (LP) gas container in the trunk 
or other sealed off space within the interior of the vehicle. The NFPA58 
requires the following:  
¥  
Any space containing radio equipment shall be isolated by a seal from the 
VEHICLES EQUIPPED WITH AIR BAGS
An air bag inßates with great force. DO NOT place objects, including 
communication equipment, in the area over the air bag or in the air bag 
deployment area. If the communication equipment is improperly 
installed and the air bag inßates, this could cause serious injury.   
						

							 
Safety 1 
space in which the LP gas container and its fittings are located.  
¥  
Removable (outside) filling connections shall be used.  
¥  
The container space shall be vented to the outside. 
Anti-Lock Braking System (ABS) and 
Anti-Skid Braking System Precautions 
Disruption of the anti-skid/anti-lock braking system by the radio 
transmitter may result in unexpected vehicle motion.  
Motorola recommends the following radio installation precautions and 
vehicle braking system test procedures to ensure that the radio, when 
transmitting, does not interfere with operation of the vehicle braking system. 
Installation Precautions 
1. Always provide as much distance as possible between braking modulator 
unit and radio, and between braking modulator unit and radio antenna 
and associated antenna transmission line. Before installing radio, 
determine location of braking modulator unit in vehicle. Depending on 
make and model of vehicle, braking modulator unit may be located in 
trunk, under dashboard, in engine compartment, or in some other cargo 
area. If you cannot determine location of braking modulator unit, refer 
to vehicle service manual or contact a dealer for the particular make of 
vehicle.
2. If braking modulator unit is located on left side of the vehicle, install 
radio on right side of vehicle, and conversely. 
3. Route all radio wiring including antenna transmission line as far away as 
possible from braking modulator unit and associated braking system 
wiring.
4. Never activate radio transmitter while vehicle is in motion and vehicle 
trunk lid is open. 
Braking System Tests 
The following procedure checks for the most common types of interference 
that may be caused to vehicle braking system by a radio transmitter.
1. Run vehicle engine at idle speed and set vehicle transmission selector to 
PARK. Release brake pedal completely and key radio transmitter. Verify 
that there are no unusual effects (visual or audible) to vehicle lights or 
other electrical equipment and accessories while microphone is NOT 
being spoken into.
2. Repeat step 1. except do so while microphone IS being spoken into.
3. Press vehicle brake pedal slightly just enough to light vehicle brake 
light(s). Then repeat step 1. and step 2.
4. Press the vehicle brake pedal firmly and repeat step 1. and step 2.
5. Ensure that there is a minimum of two vehicle lengths between front of 
vehicle and any object in vehicleÕs forward path. Then, set vehicle 
!
W A R N I N G
! 
						

							 
Safety 2 
transmission selector to DRIVE. Press brake pedal just far enough to stop 
vehicle motion completely. Key radio transmitter. Verify that vehicle 
does not start to move while microphone is NOT being spoken into.
6. Repeat step 5. except do so while microphone IS being spoken into.
7. Release brake pedal completely and accelerate vehicle to a speed between 
15 and 25 miles/25 and 40 kilometers per hour. Ensure that a minimum 
of two vehicle lengths is maintained between front of vehicle and any 
object in vehicleÕs forward path. Have another person key radio 
transmitter and verify that vehicle can be braked normally to a moderate 
stop while microphone is NOT being spoken into.
8. Repeat step 7. except do so while microphone IS being spoken into.
9. Release brake pedal completely and accelerate vehicle to a speed of 20 
miles/30 kilometers per hour. Ensure that a minimum of two vehicle 
lengths is maintained between front of vehicle and any object in 
vehicleÕs forward path. Have another person key radio transmitter and 
verify that vehicle can be braked properly to a sudden (panic) stop while 
microphone is NOT being spoken into.
10. Repeat step 9. except do so while microphone IS being spoken into.
11. Repeat step 9. and step 10. except use a vehicle speed of 30 miles/50 
kilometers per hour. 
						

							 
List of Effective Pages A 
LIST OF EFFECTIVE PAGES  
MCS 2000 Mobile Radio Service Instructions
Volume 2g
VHF Frequency Range, 25W Specific Information
Motorola Publication Number 68P81080C48-O 
I  
ssue Dates of Original and Revised Pages are: 
Revision O: December1998 
The Number of pages in this publication is 50 consisting of the
following: 
Note: The letter O in the Revision Letter column of the table above denotes an original page. Original pages 
ARE NOT identified as such in the page footors except by the absence of a change letter and date. 
Page Number
Revision LetterPage NumberRevision Letter
Front cover O 1 through 36 O
Inside front cover (blank) O Questionnaire (Front) O
Title O Questionnaire (Back) O
Safety 0 through
Safety 2O Inside Back Cover 
(Replacement Parts 
Ordering)C
A  and B O Back Cover (Not 
Marked with Revision 
LetterO
i and ii O
  
						

							 
 B          
IMPORTANT 
ELECTROMAGNETIC 
EMISSION 
INFORMATION 
In August, 1996, The Federal Communications Commission (FCC) 
adopted an updated safety standard for human exposure to radio 
frequency electromagnetic energy emitted by FCC regulated 
equipment. Motorola subscribes to this same updated safety standard 
for the use of its products.
In keeping with sound installation practice and to maximize radiation 
efficiency, a one-quarter (1/4) wave length antenna should be installed 
at the center of the vehicle roof. If it is necessary to mount the 
antenna on the vehicles trunk lid, an appropriate 3db gain antenna 
should be used. This installation procedure will assure that vehicle 
occupants will be exposed to radio frequency energy levels lower than 
the limits specified in the standard adopted by the FCC in General 
Docket 79144.
To assure that radio frequency (RF) energy exposure to bystanders 
external to a vehicle is lower than that recommended by FCC adopted 
standard, transmit with any mobile radio only when bystanders are at 
least two (2) feet away from a properly installed externally mounted 
antenna for radios with less than 50 watts of output power, or three (3) 
feet away for radios with 50 watts or greater power.  
Control Station Operation  
In the event of Control Station operation, to assure operators and 
bystanders are exposed to radio frequency (RF) energy levels lower 
than the limits specified in the FCC adopted standard, the antenna 
should be installed outside of any building, but in no instance shall 
the antenna be within two feet (less than 50 watts power output) or 
within three feet (50 watts or higher power output) of station 
operators or bystanders.   
						

							 
Table of Contents i 
Table of Contents 
Safety Information  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Safety 0
List of Effective Pages  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  A
Important Electromagnetic Emission Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  ii
List of Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  ii
1- Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2- Theory of Operation  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
Block Diagram Level Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Receiver Detailed Functional Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
  Receiver Front End  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  7
  Receiver Intermediate Frequency (IF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  8
  Receiver Back End . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  8
Transmitter Detailed Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
  Synthesizer Detailed Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
  Power Amplifier  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  11
    Overall PA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  11
    PA Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  13
Controller Detailed Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  14
Dc Power Control and Regulation Detailed Functional Description . . . . . . . . . . . . . . . . . . . . . . .  14  
4 - Reference Drawings  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15   
						

							 
ii List of Figures                                                                                                       
List of Figures 
Figure 1.  Overall Radio Functional Block Diagram  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Figure 2.  Transceiver Board Section Locations   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 
List of Tables 
Table 1. Schematic Diagram Interconnection List  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Note 
:    
Reference drawings (component locations, schematic diagrams, and parts lists) are listed
on page15 
. 
						

							 
Introduction 1 
Introduction 
1 
This publication (Service Manual Volume 2g, Motorola Publication 
68P81080C48) provides frequency-range-specific information for the 
25-Watt MCS 2000 radio that operates in the VHF frequency range 
(136 to 174 MHz).
This publication is a companion volume to Service Manual Volume 1 
for MCS 2000 Radios, Motorola Publication Number 68P81083C20, 
which provides non-frequency-range-specific information for all MCS 
2000 Radios. Service personnel must have both Volume 1 and Volume 
2d of this Service Manual in order to have all service information for 
the 25-Watt MCS 2000 Radio that operates in the VHF frequency 
range.
There are other Volume 2 service manuals (e.g., Volume 2b, 2c, 2d,), 
which cover models of the MCS 2000 Radio for other frequency ranges 
and power levels. Refer to Volume 1 of this service manual for a list of 
the manuals related to operation and maintenance of all models of the 
MCS 2000 Radio, and the Motorola publication numbers for those 
manuals.
Hereafter in this manual, the MCS 2000 Radio is referred to as the 
radio. The specific hardware portions of the radio covered in this 
volume of the service manual are as follows:  
¥  
Receiver Front End  
¥  
Receiver Intermediate Frequency (IF)  
¥  
Receiver Back End  
¥  
Power Amplifier  
¥  
Synthesizer
This volume (Volume 2g) of the service manual covers the following 
four topics for the specific hardware portions of the  VHF radio:  
¥  
Theory of operation  
¥  
Component locations  
¥  
Parts lists  
¥  
Schematic diagrams and associated interconnect information   
						

							 
2 Introduction 
The four topics listed above for the controller section and for the 
control heads are covered in Volume 1 of this service manual, 
Motorola Publication Number 68P81083C20.
All the radios covered in this service manual contain a single circuit 
card assembly (a printed circuit board with components mounted), 
which is called the transceiver board.