Motorola radio communications products are warranted to be free from defects in material and
workmanship for a period of ONE (1) YEAR, (except for crystals and channel elements which are
warranted for a period of ten (10) years) from the date of shipment. Parts, including crystals and
channel elements, will be replaced free of charge for the full warranty period but the labor to replace
detective parts will only be provided for One Hundred-Twenty (120) days from the date of shipment.
Thereafter purchaser must pay for the labor involved in repairing the product or replacing the parts at
the prevailing rates together with any transportation charges to or from the place where warranty
service is provided. This express warranty is extended by Motorola Communications and Electronics
Inc., 1301 E. Algonquin Road, Schaumburg, Illinois 60196, to the original purchaser only, and only
to those purchasing for purpose of leasing or solely for commercial, industrial, or governmental use.
THIS WARRANTY IS GIVEN IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED WHICH
ARE SPECIFICALLY EXCLUDED, INCLUDING WARRANTIES OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MOTOROLA BE LIABLE FOR INCIDENTAL
OR CONSEQUENTIAL DAMAGES TO THE FULL EXTENT SUCH MAY BE DISCLAIMED BY LAW.
In the event of a defect, malfunction or failure to conform to specifications established by Seller, or if
appropriate, to specifications accepted by Seller in writing, during the period shown. Motorola, at its
option, will either repair or replace the product or refund the purchase price thereof, and such action
on the part of Motorola shall be the full extent of Motorola's liability hereunder.
This warranty is void if:
1. The product is used in other than its normal and customary manner.
2. The product has been subject to misuse, accident, neglect or damage.
3. Unauthorized alterations or repairs have been made, or unapproved parts used in the equipment.
This warranty extends only to individual products, batteries are excluded, but carry their own
separate limited warranty. Because each radio system is unique, Motorola disclaims liability for range,
coverage, or operation of the system as a whole under this warranty except by a separate written
agreement signed by an officer of Motorola.
Non-Motorola manufactured products are excluded from this warranty, but subject to the warranty
provided by their manufacturers, a copy of which will be supplied to you on specific written request.
To obtain performance of this warranty, purchaser must contact mobat_support@mobatUSA.com.
This warranty applies only within the United States.
COMPUTER SOFTWARE COPYRIGHTS
The Motorola products described in this instruction manual may include copyrighted Motorola
computer programs stored in semiconductor memories or other media. Laws in the United States
and other countries preserve for Motorola certain exclusive rights for copyrighted computer
programs, including the exclusive right to copy or reproduce in any form the copyrighted computer
program. Accordingly, any copyrighted Motorola computer programs contained in the Motorola
products described in this instruction manual may not be copied or reproduced in any manner
without the express written permission of Motorola. Furthermore, the purchase of Motorola products
shall not be deemed to grant either directly or by implication, estoppel, or otherwise, any license
under the copyrights, patents or patent applications of Motorola, except for the normal nonexclusive, royalty free license to use that arises by operation of law in the sale of a product.
Chapter 7 Schematic Diagrams, Layouts and Parts Lists .....................................................7-1
ii Cat. No. 6886859J01
Page 7
Performance Specifications
MICOM-3F – Model M90AMNOKV5-K
MICOM-3T – Model M91AMNOKV5-K
MICOM-3R – Model M95AMNOKV5-K
General
Transmit Frequency Range
Receive Frequency Range
RF Input Impedance
Number of Channels
Scanning
Frequency Stability
Frequency Drift (Aging)
Synthesizer Lock Time
Frequency Resolution
Operating Temperature Range
Storage Temperature Range
1.6 to 30 MHz
0.1 to 30 MHz (0.1 to 1.6 MHz reduced
performance)
50 Ω
200 simplex or half duplex, user
programmable
5 groups with up to 100 channels per group,
including 1 guard channel.
Programmable scan rate: 1 to 5 sec. per
channel, in 1 sec. steps
0.6 ppm (0.1 ppm optional) @ -30° to 60°C
1 ppm/year
10 msec. max.
10 Hz
-30° to +60°C
-40° to +85°C
Humidity
Remote Control Interface
Modes of Operation
Operating Voltage
Dimensions
MICOM-3F
MICOM-3R
MICOM-3T
Max. 95% @ 50°C
RS-232C (optional)
• ]3E SSB
• R3E PILOT
• H3E AME
• J2ACW
• J2B RTTY, ARQ, FEC, PACKET, MCW
• B8C FAX, DATA, FSK
13. 8 VDC ±20%, negative ground
92 H × 302 W × 270 D mm
(3.7 H × 11.9 W × 10.7 D inch)
92 H × 302 W × 285 D mm
(3.7 H × 11.9 W × 11.3 D inch)
92 H × 302 W × 285 D mm
(3.7 H × 11.9 W × 11.3 D inch)
Cat. No. 6886859J01 iii
Page 8
Current
Consumption
@ 13.8 VDC
FCC
Information
Weight
MICOM-3F
MICOM-3R
MICOM-3T
ALE
Transmit
Voice (125 W P.E.P)
2 Tones (125 W P.E.P)
Single Tone
Receive
Full Audio
Squelch
Transmitter Peak Envelope Power
(P.E.P)
Frequency Range
5.7 kg (12.5 lb)
5.9 kg (13 lb)
5.8 kg (12.8 lb)
Per FED-STD-1045 and MIL-STD-188/141B
14 A (see Note 2 on page vi)
23 A
28 A
3 A (see Note 2 on page vi)
2.2 A (see Note 2 on page vi)
125 W
1.6 to 30 MHz
Military and
Industrial
Standards
Emissions Authorized
Applicable Parts of FCC Rules
FCC Type Acceptance Number
Standard for Stability
0.1 ppm High Stability Option
Vibration
Shock
Rain
Dust
Salt Fog
J3E, R3E, H3E, J2A, J2B, B8C
15, 80, 90
ABZ9QCC1635
ABZ9QCC1634
US MIL-STD 810C Method 514.2
US MIL-STD 810D 514.3
US MIL-STD 810E 514.4
US MIL-STD 810C Method 516.2
US MIL-STD 810D 516.3
US MIL-STD 810E 516.4
US MIL-STD 810C Method 506.1
US MIL-STD 810D 506.2
US MIL-STD 810E 506.3
US MIL-STD 810C Method 510.1
US MIL-STD 810D 510.2
US MIL-STD 810E 510.3
US MIL-STD 810C Method 509.1
US MIL-STD 810D 509.2
US MIL-STD 810E 509.3
iv Cat. No. 6886859J01
The MICOM-3 also meets the EIA-RS152B for shock, vibration and applicable test
procedures, US FCC for channel occupancy, spurious, interference and frequency
tolerance. It is manufactured according to the demanding standards of ISO 900
and EMC (Electromagnetic Compatibility).
Page 9
Transmitter
Output Power
125 W P.E.P and average
Reduced Power Levels
Audio Bandwidth
Voice
CW
Low Speed Data
High Speed Data
Audio Bandwidth Ripple
Intermodulation
Harmonic Emissions
Spurious Emissions
Carrier Suppression
Undesired Sideband Suppression
Audio Distortion
25 W, 62 W, 100 W (RSS programmable)
350 to 2700 Hz at -6 dB
650 to 1150 Hz
1450 to 1950 Hz
350 to 3300 Hz (see Note 2 on page vi)
3 dB
• -31 dB/P.E.P
• -35 dB/P.E.P typical (see Note 1 on page vi)
• -64 dB/P.E.P
• -70 dB/P.E.P typical (see Note 1 on page vi)
• -64 dB/P.E.P
• -70 dB/P.E.P typical (see Note 1 on page vi)
-50 dB/P.E.P
-55 dB/P.E.P
2.5%
Receiver
1/2 Power Microphone Sensitivity
Hum & Ripple
Inband Noise
TX/RX Switching Time
Tx Tuning Adjustments
Sensitivity (SINAD) SSB
1/2 Rated Power Sensitivity
Selectivity
Image Rejection
IF Rejection
Undesired Sideband Rejection
Spurious
25 to 125mV (RMS)/600 Ω
-50 dB
-60 dB (30 Hz BW)
10 msec
None
• 0.5 µV for 10 dB SINAD
• 0.35 µV typical (see Note 1 on page vi)
• 0.1 to 1.6 MHz with reduced performance
1 µV for 2.5W audio at speaker
-6 dB @ 350 to 2700 Hz
-60 dB @-1 kHz; +4 kHz
-80 dB
-85 dB
-55 dB @ -1 kHz
-80 dB
Cat. No. 6886859J01 v
Intermodulation
Crossmodulation
Desensitization
-80 dB
-100 dB @ 100 kHz
-100 dB @ 100 kHz
Page 10
Reciprocal Mixing
Audio Power at Speaker
RGC Range
RGC Time Constants
Voice
-100 dB @ 100 kHz
5W @ 2.5% distortion
5 µV to 1V (2 dB change in output level)
Attack time 10 msec
Release time 1500 msec
Data
Attack time 10 msec
Release time 10 msec
Controls
Squelch
Clarifier Range
Receiver Tuning Adjustments
Preselector Sections
Maximum Antenna Input
Standard and optional: Volume, on/off, scroll, squelch, scan, USB/LSB, call,
Constant SINAD (digital)
±200 Hz in 10 Hz steps (see Note 2 on page vi)
None
Sub-octave (1.6 MHz to 30 MHz range)
20 kV transient, 100V RMS for 2 minutes
monitor, priority, function and accessory/programming connector
Note 1: Values noted as "Typical" are valid over 90% or more of the frequency range.
Note 2: Optional for authorized dealers only.
Specifications subject to change without notice.
vi Cat. No. 6886859J01
Page 11
MICOM-3F Model Complements
FKN4345A DC Cable
FLN2776A Control Head Assembly
FTN6069A Control Head Board
FLN2774A High Power Assembly
FTN6068A High Power Board
FLN2773A Low RF Assembly
FTN6067A Low RF Board
FMN1615A Microphone MICOM-3
FHN5910A MICOM-3 Microphone Module
HMN3596A GM300 Microphone Kit
6802941C60 MICOM-3 Owner's Manual
Operating Options
G424 Add PC Control and Programming Software Package
S135 Enhanced Digital Noise Blanker (recommended for mobile installations)
G112 Enhanced High frequency stability option (0.1 ppm)
G419 Enhanced USB COM port for connecting external keyboard
G423 Add ALE DTM/DBM (data transfer message/data block message)
G421 Add Internal GPS Receiver with polling application
G849 Interface option for external secure voice device (VP-116)
Mobile Station Accessories
FAD1410 Automatic Tuning Whip Antenna
or
F2265 Automatic Antenna Tuner
1.6-30 MHz, lightweight, compact housing, includes 17 foot (5.2 m)
RF cable and instruction manual
FAD1400 12 ft Whip Antenna (not required with FAD1410)
FLN2272 Mobile Mounting Kit
FSN1600 External Speaker Assembly
Cat. No. 6886859J01 vii
Page 12
Fixed Station Operating Options (Note 2)
S71 Delete Delete hand microphone
S308 Add Phone patch interface cable kit, radio to phone patch (Note 1)
G561 Add Interface cable for MICOM Link unit
Fixed Station Accessories
FMN1614 Desk microphone
FLN2271 Junction box for connecting up to 4 accessories in addition to CW key and
headphones (Note 1)
FLN2294 Package kit for continuous duty data transmission. Includes FLN2271
junction box
FPN5590 AC Power supply with autoswitching for 110/220VAC
Service Manuals
6886859J01 MICOM-3F/3T/3R Service Manual
6886862J01 Service manual for MICOM-RM1000 1kW linear amplifier
Field Retrofit Kits
FLN2515 Interface cable kit for CW key & Headphones
FLN2517 Interface cable kit for Phone patch unit
FLN2530 Interface cable for MICOM Link unit
FLN2539 24VDC Operation (DC/DC converter)
FVN4841 PC Control and Programming Software Package
Remote Control Application Option
G420 2-wire Remote Control Head (up to 5 km)
1 kW Linear Amplifier
FLN3175 MICOM-RM1000 1 kW Linear Amplifier Unit (require option G156
interface cable option)
Spare Boards Kit
FEN1672 Recommended Spare Boards Kit for MICOM-3F
viii Cat. No. 6886859J01
Page 13
4 Year Extended Warranty
FRN8465 4 Year Warranty for MICOM-3F
Note 1: The MICOM-3 includes one accessory port for connecting one accessory device (phone
patch, deskset, ARQ/RTTY modem, fax modem, computer, or headphones). If the
simultaneous connection of two or more (up to 4 plus CW & headphones) devices to the
accessory port is required, order FLN2271 junction box listed in this page. The FLN2271 is
included with FLN2294 package kit.
Note 2: For Fixed Station Operation, order S71 (delete palm microphone), FMN1614 desk
microphone and F2369 AC power supply/charger.
Cat. No. 6886859J01 ix
Page 14
MICOM-3T Model Complements
FKN4345A DC Cable
FLN2775A Control Head Assembly
FTN6070A Control Head Board
FLN3173A High Power Assembly
FTN6068A High Power Board
FLN2773A Low RF Assembly
FTN6067A Low RF Board
FMN1615A Microphone MICOM-3
FHN591UA MICOM-3 Microphone Module
HMN3596A GM300 Microphone Kit
6886867J01 MICOM-3F/3T/3T Owner's Guide
Operating Options
G424 Add PC Control and Programming Software Package
G112 Enhanced High frequency stability option (0.1 ppm)
G419 Enhanced USB COM port for connecting external keyboard
G423 Add ALE DTM/DBM (data transfer message/data block message)
G421 Add Internal GPS Receiver with polling application
G849 Interface option for external secure voice device (VP-116)
Mobile Station Accessories
FAD1410 Automatic Tuning Whip Antenna
or
F2265 Automatic Antenna Tuner
1.6-30 MHz, lightweight, compact housing, includes 17 foot (5.2 m)
RF cable and instruction manual
FAD1400 12 ft Whip Antenna (not required with FAD1410)
FLN2272 Mobile Mounting Kit
FSN1600 External Speaker Assembly
x Cat. No. 6886859J01
Page 15
Fixed Station Operating Options (Note)
S71 Delete Delete hand microphone
S308 Add Phone patch interface cable kit, radio to phone patch (Note 1)
G561 Add Interface cable for MICOM Link unit
Fixed Station Accessories
FMN1614 Desk microphone
FLN2271 Junction box for connecting up to 4 accessories in addition to CW key and
headphones (Note 1)
FLN2294 Package kit for continuous duty data transmission. Includes FLN2271
junction box
FPN5590 AC Power Supply with Autoswitching for 110/220 VAC
Service Manuals
6886859J01 MICOM-3F/3T/3R Service Manual
Field Retrofit Kits
FLN2515 Interface cable kit for CW key & headphones (Note)
FLN2517 Interface cable kit for phone patch unit (Note)
FLN2530 Interface cable for MICOM Link unit
FLN2539 24VDC Operation (DC/DC converter)
Spare Boards Kit
FEN1673 Recommended Spare Boards Kit for MICOM-3T
4 Year Extended Warranty
FRN8466 4 Year Warranty for MICOM-3T
Note: The MICOM-3T includes one accessory port for connecting one accessory device (phone
patch, deskset, ARQ/RTTY modem, fax modem, computer, or headphones). If the
simultaneous connection of two or more (up to 4 plus CW & Headphones) devices to the
accessory port is required, order FLN2271 junction box listed in this page. The FLN2271 is
included with FLN2294 package kit.
Cat. No. 6886859J01 xi
Page 16
MICOM-3R Model Complements
FKN4345A DC Cable
FLN2777A Control Head Assembly
FTN6069A Control Head Board
FLN3174A High Power Assembly
FTN6068A High Power Board
FLN2773A Low RF Assembly
FTN6067A Low RF Board
6886867J01 MICOM-3F/3T/3R Owner's Guide
Operating Options
G424 Add PC Control and Programming Software Package
G112 Enhanced High frequency stability option (0.1 ppm)
G419 Enhanced USB COM port for connecting external keyboard
G423 Add ALE DTM/DBM (data transfer message/data block message)
G421 Add Internal GPS Receiver with polling application
G849 Interface option for external secure voice device (VP-116)
Mobile Station Accessories
FLN2537 Automatic Antenna Tuner
1.6 to 30 MHz, lightweight, compact housing, includes 17 foot (5.2 m)
RF cable and instruction manual
FLN2538 Mobile Mounting Kit
Fixed Station Operating Options
S308 Phone patch interface cable kit, radio to phone patch (Note 1)
G561 Interface cable for MICOM Link unit
Military Type Audio Accessories
FMN5501 Military type Handset (H-250/U)
FSN5503 Military type External Speaker (LS-454/U)
xii Cat. No. 6886859J01
Page 17
Fixed Station Accessories (Note)
FLN2271 Junction box for connecting up to 4 accessories in addition to CW key and
headphones
FLN2294 Package kit for continuous duty data transmission. Includes FLN2271
junction box
FPN5590 AC Power supply with autoswitching for 110/220VAC
Service Manuals
6886859J01 MICOM-3F/3T/3R Service Manual
Field Retrofit Kits
FKN4403 Interface cable kit for CW key & headphones (Note)
FKN4404 Interface cable kit for phone patch unit (Note)
FKN4405 Interface cable kit for fax modem (Note)
FKN4406 Interface cable kit for RTTY/ARQ modem (Note)
FLN2273 Spare RSS software package (Note)
Remote Control Application Option
G420 2-wire Remote Control Head (up to 5 km)
Spare Boards Kit
FEN1674 Recommended Spare Boards Kit for MICOM-3R
FEN1678 Recommended Spare Module Package for MICOM-RM1000 1 kW Linear
Amplifier
4 Year Extended Warranty
FRN8467 4 Year Warranty for MICOM-3R
FRN8470 4 Year Warranty for MICOM-RM1000 1 kW Linear Amplifier
Note: The MICOM-3R includes one accessory port for connecting one accessory device (phone
patch, deskset, ARQ/RTTY modem, fax modem, computer, or headphones). If the
simultaneous connection of two or more (up to 4 plus CW & Headphones) devices to the
accessory port is required, order FLN2271 junction box listed in this page. The FLN2271 is
included with FLN2294 package kit.
Cat. No. 6886859J01 xiii
Page 18
Related Publications Available Separately
The following documents offer additional information:
6886867J01 MICOM-3F/3T/3T Owner's Guide
68P02942CSD MICOM-3 HF-SSB Transceiver, 1.6-30 MHz, 125 W P.E.P and Average,
Radio Service Software, User’s Guide
xiv Cat. No. 6886859J01
Page 19
Chapter 1
Introduction
1-1. Notational Conventions
Throughout the text in this publication, you will notice the use of warnings, cautions and notes. These
notations are used to emphasize that safety hazard exist, and care must be taken and observed.
This Warning symbol denotes a hazard. It calls attention to a procedure
or practice that could result in personal injury if not performed correctly.
Warning
Caution
Note
Throughout this manual, MICOM-3F, MICOM-3T and MICOM-3R are referred to as MICOM-3.
The Caution symbol denotes a hazard. It calls attention to a procedure or
practice that could result in damage to or destruction of part or all of the
product if not performed correctly.
An operational procedure, practice or condition, etc., which is essential to
emphasize.
1-2. Scope of this Manual
This manual includes model/kit information, specifications, disassembly/reassembly procedures,
alignment, troubleshooting, and all theory, schematic diagrams, printed circuit board details and parts
lists for all parts in the equipment described.
Caution
This manual is intended for use by experienced technicians who are familiar
with similar types of equipment.
Cat. No. 6886859J01
1-1
Page 20
1-3. Federal Communication Commission Regulations
The FCC has established limits for safe exposure to radio frequency (RF) emissions from mobile
two-way radios. The FCC requires manufacturers to demonstrate compliance with RF exposure
limits before mobile two-way radios can be marketed In the U.S. When two-way radios are
approved for occupational/controlled environment exposure limits, the FCC requires users to be
fully aware of, and exercise control over, their exposure. Awareness and control of RF exposure
can be accomplished by education or training through appropriate means such as information
and instructions in user manuals or safety booklets, or other appropriate means. This user safety
booklet includes useful information about RF exposure and helpful instructions on how to
control your RF exposure.
Your Motorola two-way radio is designed and tested to comply with a number of national and
international standards and guidelines (listed below) regarding human exposure to radio frequency
electromagnetic energy. This radio complies with the IEEE (FCC) and ICNIRP exposure limits for
occupational/controlled RF exposure environments at usage factors of up to 50% talk-50% listen.
In terms of measuring RF energy for compliance with FCC exposure guidelines, your radio radiates
measurable RF energy only while it is transmitting (during talking), not when it is receiving
(listening) or in standby mode.
Your Motorola two-way radio complies with the following RF energy exposure standards and
guidelines:
• United States Federal Communications Commission, Code of Federal Regulations; 47CFR part 2
sub-part J
• American National Standards Institute (ANSI) / Institute of Electrical and Electronic Engineers
(IEEE) C95.1-1992
• Institute of Electrical and Electronic Engineers (IEEE) C95.1-1999 Edition
• International Commission on Non-Ionizing Radiation Protection (ICNIRP) 1998
• Ministry of Health (Canada) Safety Code 6: Limits of Human Exposure to Radiofrequency
Electromagnetic Fields in the Frequency Range from 3 kHz to 300 GHz, 1999
• Australian Communications Authority Radiocommunications (Electromagnetic Radiation –
Human Exposure) Standard, 2001
• ANATEL, Brasil Regulatory Authority, Resolution 256 (April 11, 2001: Additional Requirements
for SMR, Cellular and PCS Product Certification.
1-3.1 Compliance and Control Guidelines and Operating Instructions for
Mobile Two-Way Radios Installed in Vehicles
To control your exposure and ensure compliance with the occupational/ controlled environment
exposure limits, always adhere to the following procedures:
• To transmit (talk), push the Push-To-Talk (PTT) button; to receive, release the PTT button.
Transmit only when people outside the vehicle are at least the minimum lateral distance
away (as shown in table below) from a properly installed, externally-mounted antenna.
The table below lists the minimum lateral distance for bystanders in an uncontrolled environment
from the transmitting antenna at several different ranges of rated radio power for mobile radios
installed in a vehicle.
1-2
Cat. No. 6886859J01
Page 21
Rated Power of Vehicle-Installed Mobile
Two-Way Radio
Less than 7 watts 8 inches (20 centimeters)
7 to 15 watts 1 foot (30 centimeters)
16 to 50 watts 2 feet (60 centimeters)
51 to 110 watts 3 feet (90 centimeters)
Minimum Lateral Distance from
Transmitting Antenna
• Install mobile antennas at the center of the roof or the center of the trunk deck per specific
guidelines and instructions in the Radio Installation Manual. These mobile antenna
installation guidelines are limited to metal body vehicles.
Use only the Motorola-approved, supplied antenna or a Motorola- approved replacement
antenna. Use of non-Motorola-approved antennas, modifications, or attachments could damage
the radio and may violate FCC regulations.
• For a list of Motorola-approved antennas, visit the following web site:
http://www.motorola.com/cqiss/index.shtml.
For additional information on exposure requirements or other training information, visit
http://www.motorola.com/rfhealth
.
1-3.2 Compliance and Control Guidelines and Operating Instructions for
Mobile Two-Way Radios Installed as Fixed Site Control Stations
If mobile radio equipment is installed at a fixed location and operated as a control station or as a
fixed unit, the antenna installation must comply with the following requirements in order to ensure
optimal performance and compliance with the RF energy exposure limits in the standards and
guidelines listed in the Federal Communication Commission Regulations section.
• The antenna should be mounted outside the building on the roof or a tower if at all possible.
• As with all fixed site antenna installations, it is the responsibility of the licensee to manage the site
in accordance with applicable regulatory requirements and may require additional compliance
actions such as site survey measurements, signage, and site access restrictions in order to ensure
that exposure limits are not exceeded.
1-3.3 Electromagnetic Interference/Compatibility
Note
Nearly every electronic device is susceptible to electromagnetic interference (EMI)
if inadequately shielded, designed, or otherwise configured for electromagnetic
compatibility. It may be necessary to conduct compatibility testing to determine if
any electronic equipment used in or around vehicles or near fixed site antenna is
sensitive to external RF energy or if any procedures need to be followed to
eliminate or mitigate the potential for interaction between the radio transmitter
and the equipment or device.
Cat. No. 6886859J01
1-3
Page 22
1-3.4 Facilities
To avoid electromagnetic interference and/or compatibility conflicts, turn off your radio In any
facility where posted notices instruct you to do so. Hospitals or health care facilities may be using
equipment that is sensitive to external RF energy.
1-3.5 Vehicles
To avoid possible interaction between the radio transmitter and any vehicle electronic control
modules, for example, ABS, engine, or transmission controls, the radio should be installed only by an
experienced installer and that the following precautions be used when installing the radio:
1. Refer to the manufacturer's instructions or other technical bulletins for recommendations on
radio installation.
2. Before installing the radio, determine the location of the electronic control modules and their
harnesses in the vehicle.
3. Route all radio wiring, including the antenna transmission line, as far away as possible from the
electronic control units and associated wiring.
1-3.6 Driver Safety
Check the laws and regulations on the use of radios in the area where you drive. Always obey them.
1-3.7 When using your radio while driving, please:
• Give full attention to driving and to the road.
• Pull off the road and park before making or answering a call if driving conditions so require.
1-3.8 Operational Warnings
For Vehicles with an Air Bag
Do not mount or place a mobile radio in the area over an air bag
Warning
deployment area. Air bags inflate with great force. If a radio Is placed in
the air bag deployment area and the air bag inflates, the radio may be
propelled with great force and cause serious injury to occupants of the
vehicle.
Potentially Explosive Atmospheres
Turn off your radio prior to entering any area with a potentially explosive
atmosphere. Sparks in a potentially explosive atmosphere can cause an
explosion or fire resulting in bodily injury or even death.
1-4
The areas with potentially explosive atmospheres include fueling areas
such as below decks on boats, fuel or chemical transfer or storage
facilities, and areas where the air contains chemicals or particles such as
grain, dust or metal powders. Areas with potentially explosive
atmospheres are often, but not always, posted.
Cat. No. 6886859J01
Page 23
Blasting Caps and Blasting Areas
To avoid possible interference with blasting operations, turn off warning
Warning
your radio when you are near electrical blasting caps, in a blasting area,
or in areas posted: "Turn off two-way radio". Obey all signs and
instructions.
For radios installed in vehicles fueled by liquefied petroleum gas, refer to
the (U.S.) National Fire Protection Association standard, NFPA 58, for
storage, handling, and/or container information. For a copy of the LP-gas
standard, NFPA 58, contact the National Fire Protection Association, One
Battery Park, Quincy, MA.
1-3.9 Restrictions
Because this radio contains a transmitter, federal law prohibits unauthorized, non-licensed personnel
from adjusting or maintaining it. If any operational difficulties should arise while using this product,
report them to authorized service personnel as soon as possible.
Do not attempt any unauthorized modification to the radio.
Warning
1-4. Safe Handling of CMOS Devices
Complementary metal-oxide semiconductor (CMOS) devices are used in this family of radios. While
the attributes of CMOS are many, their characteristics make them susceptible to damage by
electrostatic or high voltage charges. Damage can be latent, resulting in failures occurring weeks or
months later. Therefore, special precautions must be taken to prevent device damage during
disassembly, troubleshooting, and repair. Handling precautions are mandatory for CMOS circuits and
are especially important in low humidity conditions.
Caution
1. Eliminate static generators (plastics, styrofoam, etc.) in the work area.
2. Remove nylon or double-knit polyester jackets, roll up long sleeves, and remove or tie back
loose hanging neckties.
3. Store and transport all static-sensitive devices in ESD protective containers.
4. If at all possible, handle CMOS devices by the package and not by the leads. Prior to touching
the unit, touch an electrical ground to remove any static charge that you may have
accumulated. The package and substrate may be electrically common. If so, the reaction of a
discharge to the case would cause the same damage as touching the leads.
5. Disconnect all power from the unit before ESD sensitive components are removed or inserted,
unless otherwise noted.
Do not attempt to disassemble the radio without observing the following
handling precautions.
Cat. No. 6886859J01
1-5
Page 24
6. Use a static safeguarded workstation, which can be accomplished through the use of an antistatic kit (for example, Motorola part number 0180386A82). This kit includes a wrist strap,
two ground cords, a static-control table mat and a static-control floor mat.
When these items are not readily available, observing the following techniques will minimize
chance of damage:
• If a static-sensitive device is to be temporarily set down, use a conductive surface for
placement of the device.
• Make skin contact with a conductive work surface first and maintain this contact when
the device is set down or picked up.
7. Always wear a conductive strap when servicing this equipment. The Motorola part number for
a replacement wrist strap that connects to the table mat is 42-80385A58.
8. When straightening CMOS pins, provide ground straps for apparatus used.
9. When soldering, use a grounded soldering iron.
1-6
Cat. No. 6886859J01
Page 25
Chapter 2
Test Equipment & Spare
Parts
2-1. Test Equipment
The list in Table 2-1 includes the standard test equipment required for servicing the MICOM-3 radios.
Table 2-1. Test Equipment
Model No. Description Comments
R2670 Motorola Communication Analyzer
HP 8904A Multi-function Synthesizer
Pentium 3 or Better Personal Computer
Cat. No. 6886859J01 2-1
Page 26
2-2. Spare Parts
The lists in Table 2-2 to Table 2-5 include all the recommended spare part kits and components.
Note
The spare parts marked with an asterisk in Table 2-2 to Table 2-5 are plant
items.
Table 2-2. Spare Parts Common to All MICOM-3 Models
Manufacturer Kit/Part Number Description
FTN6067A (for standard radio with
Low RF and Digital (LORD) board
0.6 ppm frequency stability)
FTN6068A High Power board
0102701K52 Harmonic Filter module
4808115L07 PIN diode
2409646B25
4808020K01
4808020K02
Coil, 100 µHy
Final stage transistor (×2)
Driver transistor (×2)
FRN4345 DC cable
6500020986 Fuse, 30A
6500086099 Fuse, 7.5A
0102701K51 Flat cable (from Control Head to LORD board)
0102700K23 Flat cable (from High-Power to LORD board)
0102700K22 Internal coax
0102703K64 Battery assembly
FMN1615 Microphone
2-2 Cat. No. 6886859J01
Page 27
Table 2-3. Spare Parts for MICOM-3F – Model M90AMNOKV5-K
Manufacturer Kit/Part Number Description
FLN2776A Control Head Assembly
*20724811000 Front Panel
*20724821000 Window
*20722111400 LCD
*20724823000 Keypad
*20724822000 Left keypad
3608147K01 Volume knob, interior
3605422W02 Volume knob, exterior
5008351Y01 Speaker
3280603K01 Gasket, speaker
3204071P02 Gasket, panel
*20724812000 Set cables
FTN6069A Control Head board
2802101U01 Zebra connector for LCD
2802102U01 Zebra connector for LCD
Cat. No. 6886859J01 2-3
Page 28
Table 2-4. Spare Parts for MICOM-3T – Model M91AMNOKV5-K
Manufacturer Kit/Part Number Description
HKN6098A Remote cable
3286211C01 Gasket, remote panel
FLN2775A Control Head Assembly
*20724811000 Front panel
*20724814000 Back panel
*20724821000 Window
*20722111400 LCD
*20724823000 Keypad
*20724822000 Left keypad
3608147K01 Volume knob, interior
3605422W02 Volume knob, exterior
5008351Y01 Speaker
3286212C01 Gasket, board to panel
*20724812000 Set cables
FTN6070A Control Head board
2802101U01 Zebra connector for LCD
2802102U01 Zebra connector for LCD
FRN5885 Interface board
0102705K85 Ground cable
0102701K51 Flat cable
2-4 Cat. No. 6886859J01
Page 29
Table 2-5. Spare Parts for MICOM-3R – Model M95AMNOKV5-K
Manufacturer Kit/Part Number Description
FLN2777A Control Head Assembly
*20724812000 Front Panel
*20724821000 Window
*20722111400 LCD
*20724823000 Keypad
*20724822000 Left keypad
3686525F01 Volume knob
0102706K34 Speaker
3286532F01 Gasket, speaker
3280605K05 Gasket, panel
*20724812000 Set cables
FTN6069A Control Head board
2802101U01 Zebra connector for LCD
Cat. No. 6886859J01 2-5
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Intentionally Left Blank
2-6 Cat. No. 6886859J01
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Chapter 3
Disassembly & Reassembly
3-1. General
The following sections provides disassembly and reassembly instructions for MICOM-3.
When tightening screws, apply controlled torques in accordance with Table 3-1. The allowed torque
tolerance is ±10%.
Table
3-1. Tightening Torque for Metric System Screws
Screw Size
(millimeter)
M3 10 kgf/cm 10 kgf/cm 6 kgf/cm
M4 15 kgf/cm 15 kgf/cm 7 kgf/cm
M5, M6 22 kgf/cm 18 kgf/cm 8 kgf/cm
Table
Screw Size
(inch)
4-40 10 kgf/cm 7 kgf/cm 6 kgf/cm
6-32 15 kgf/cm 15 kgf/cm 7 kgf/cm
8-32, 10-32 22 kgf/cm 18 kgf/cm 8 kgf/cm
Thread Forming
Metallic Surface
3-2. Tightening Torque for American System Screws
Thread Forming
Metallic Surface
Threaded Metallic
Surface
Threaded Metallic
Surface
Plastic
Surface
Plastic
Surface
Cat. No. 6886859J01 3-1
Page 32
3-2. MICOM-3 Disassembly
Note
The numbers in parentheses refer the subassembly or component number in the
MICOM-3 or Control Head exploded views at the end of this manual.
3-2.1 Removing the Control Head
3-2.1.1 Removing the MICOM-3F Control Head
1. Insert a small flat blade screw driver, or similar, in the slotted area on the right hand-side panel
of the radio.
Figure 3-1. MICOM-3F Control Head
Removal
2. Press until the side of the control head releases.
3. Gently pull the control head away from the main board.
4. Remove the flat cable from the socket on the radio side.
Note
This procedure is also used to open the MICOM-3T control head.
3-2.1.2 Removing the MICOM-3R Control Head
1. Unscrew the four screws located on the front panel.
2. Gently pull the control head away from the main board.
3. Remove the flat cable from the socket on the radio side.
4. in case you require to remove the handle, unscrew the fixing screws.
Figure 3-2. MICOM-3R Control Head
Removal
3-2 Cat. No. 6886859J01
Page 33
3-2.1.3 Removing the MICOM-3T Front Cover
Release the four screws of the front cover.
Figure 3-3. MICOM-3T Front Cover
Removal
3-2.2 Removing the Cover (8)
See the corresponding MICOM-3 exploded view.
1. Remove the 2 screws (15) securing the cover (8) to the chassis (1).
2. Lift the cover over the chassis.
3. Remove the 2 RF coax cables (16) and the 40-pin flat cable (3).
3-2.3 Removing the RF Shield (13)
See the corresponding MICOM-3 exploded view.
1. Release the 6 screws (14) of the RF shield (12).
2. Remove the RF shield (12) and upper contacts (11) by gently prying up each corner of the
shield.
3-2.4 Removing the High Power Board (4)
See the corresponding MICOM-3 exploded view.
1. Remove the PA shield (7).
2. Unplug the antenna connector from the PCB.
3. Remove the screws (5) and (6) securing the High Power board to the radio chassis.
4. Remove the screws securing the power transistors and the final transformers.
5. Remove the 4 screws securing the 4 regulators.
6. Carefully remove the High Power board (4) by rotating it out of the chassis.
3-2.5 Control Head Disassembly
See the corresponding Control Head exploded view.
1. Release screw (15) from the PCB and unplug the speaker connector.
2. To pull out the printed circuit board from the control head housing, insert a small blade screw
driver in the side groove near the five protruding tabs. Remove the board from the control
head housing.
3. Remove the keypad from the PCB assembly.
4. Disconnect the board from the speaker by removing it from the socket.
Cat. No. 6886859J01 3-3
Page 34
5. Take the LCD frame or other parts out of the control head.
3-3. MICOM-3 Assembly
3-3.1 Control Head Assembly
See the corresponding Control Head exploded view.
1. Place the speaker gasket (2) on the front panel (1) with the adhesive side towards the speaker.
2. Make sure the speaker (3) including the gasket is well positioned.
3. Position the speaker spacer (4) on the speaker (3) and secure it with 4 screws (5).
4. Insert the volume knob (6) into the knob opening located on the front panel. Ensure the knob
fits and that you are able to rotate it in the clockwise direction.
5. Insert the LCD frame gasket (7) into its place.
6. Position the color sheet on the LCD frame.
7. Position the LCD display 18) onto the LCD frame and snap it into its place.
8. Insert the LCD frame with LCD and Zebra connectors into its place.
9. Place the keyboard onto the board assembly, making sure the keypad (12) is flush with the
board.
10. Rotate the knob counter-clockwise to the OFF position.
11. Position the PCB holder 114) on the PCB and snap it in place. Secure it with the screw (15).
12. Position the LCD window (16) and the logo label (17) in the front panel.
3-3.2 High Power Board Assembly
See the corresponding MICOM-3 exploded view.
1. Ensure the regulator insulators are located on the chassis.
2. Inspect and if necessary, reapply thermal grease to the heatsinking pads on the chassis.
3. Replace the PA insulator (2) on the High Power board.
4. Connect the 40-pin flat cable (3) to the High Power board connector and replace the board on
the chassis.
5. Insert the 40-pin flat cable through the opening towards the Control Head.
6. Position the High Power board correctly on the chassis (the 3-pin connector faces its recess in
the chassis).
7. Install the power transistor screws (6).
8. Install the regulator screws.
9. Install the transformer screw.
10. Install the board screws (5).
11. Connect the antenna connector plug to the PCB.
3-4 Cat. No. 6886859J01
Page 35
12. Replace the PA shield (7).
3-3.3 LORD Board Assembly
See the corresponding MICOM-3 exploded view.
1. Make sure the cover (8) including the gasket (9) is well positioned.
2. Positioned the RF shield contacts on the RF shield.
3. Replace the PCB (13) with the 25-pin connector facing its recess in the low RF chassis.
4. Place shield on the PCB and secure it with the 6 screw (14).
3-3.4 MICOM-3 Assembly
See the corresponding MICOM-3 exploded view.
1. Replace the cover (8) on the chassis (1) and secure it with 2 screws (15).
2. Connect the 2 RF coax cables (16), the 24-pin flat cable (17) and the 40-pin flat cable (3) (see
also Figure 5-9).
3. Place the front panel gasket (18) on the chassis (1) and insert the 24-pin flat cable through the
opening in the gasket.
4. Position the gasket correctly around the chassis.
5. Reinstall the Control Head or front cover as follows:
• For the MICOM-3F, press the Control Head onto the radio chassis snap until the
protruding taps on the chassis snap into the recesses inside the control housing.
• For the MICOM-3R and MICOM-3T, use the following procedure:
• Place the front panel gasket (18) on the chassis (1) and insert the 24-pin flat cable
and the ground wire through the opening in the gasket.
Note
Make sure that the front panel gasket is lubricated with NYE
Fluorocarbon 865.
• Position the gasket correctly around the chassis.
• Lock the 24-pin connector and the ground wire.
• Press the Control Head or front cover onto the radio chassis and fasten with the
four screws removed in para. 3-2.1.2 and 3-2.1.3.
Cat. No. 6886859J01 3-5
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Intentionally Left Blank
3-6 Cat. No. 6886859J01
Page 37
Chapter 4
Radio Tuning Procedure
4-1. General
Following service, three calibrations are required:
• Transmitter calibration
• Power calibration
• Oscillator calibration.
An IBM PC (personal computer) and RSS (Radio Service Software) package, G424 (FVN4841), are
required to align the radio. Refer to the RSS manual, publication number 6886867J01, for software
installation and setup procedures.
4-2. Transmitter Calibration
1. Rotate fully clockwise potentiometers R299 (driver bias) and R298 (output bias), on the HighPower board.
2. Ensure that the High-Power board heatsink temperature is 25 ±5°C and that no audio input is
present.
3. Measure Q34 or Q35 transistors base voltage. Adjust R298 until the measured base voltage is
0.63 ±0.01V.
4. Measure Q31 or Q32 drivers base voltage. Adjust R299 until the measured base voltage is
0.76 ±0.01V.
4-3. Power Calibration
Perform the power calibration according to the power calibration procedure in the RSS manual.
4-4. Oscillator Calibration
Perform the oscillator calibration according to the calibration procedure in the RSS manual.
Cat. No. 6886859J01 4-1
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Intentionally Left Blank
4-2 Cat. No. 6886859J01
Page 39
Chapter 5
Theory of Operation
5-1. Introduction
See Figure 5-3, MICOM-3 block diagram.
This section provides a functional description of the MICOM-3 radio, in the following order:
• Transmitter
• Receiver
• Synthesizer
• Electronic boards.
5-2. Transmitter
Incoming audio signal is fed directly to the DSP processor U6042 after amplification and filtration.
The DSP algorithm is translating the incoming audio signal to a stream of I and Q bits (Inphase and
Quadrature). This I/Q representation of the audio signal is transferred to the Digital SSB modulator
U6000 where a digital quadrature mixing is performed. The digital signal is then transferred to SigmaDelta D/A which converts the digital signal to an analog form. The result is the "classic" IF SSB signal
with a suppressed carrier at 1.05 MHz and "natural" suppression of the unwanted sideband. Since the
quadrature mixing is performed digitally, there are no amplitude and phase inaccuracies which may
degrade the unwanted carrier and unwanted sideband suppression. The only limiting factor is the
performance of the Hilbert transform, performed by the DSP. Since this performance is controllable,
the algorithm is designed to achieve unwanted sideband attenuation of at least 60 dB.
The 1.05 MHz IF signal is converted to 45.1 MHz IF signal at mixer U1108 and then amplified by
Q1006. The crystal filter stage cuts out unwanted mixing products and suppresses spurious signals.
This unit consists of crystal units FL1 and FL2, centered at 45.1 MHz.
The last conversion stage of the transmission path, implemented by mixer U1000, converts the signal
to the final transmission frequency.
The transmission signal is then amplified by the exciter stage Q1004, Q1005 and then transferred to
the High Power board, where it first passes the ALC attenuator Q39 and is amplified by the pre-driver
amplifier, which consists of Q2-Q6.
The Power stage consists of two transistor pairs acting as two cascaded push-pull stages the driver
stage (Q32 and Q33) is connected to the final stage (Q34 and Q35) via transformer T5. The output of
the power amplifier is transferred to a 50 Ω impedance by transformer T3.
Maximum output power is 125W PEP (Peak Envelope Power) and average at transmission duty cycle
of 1 to 4. Output power can be preprogrammed to one of 4 possible levels: 25W, 50W, 62.5W and
Cat. No. 6886859J01 5-1
Page 40
125W. Accurate sensors and the radio software keep the output power within the nominal output
power ±7.5%.
The transmitter includes thermal protections. If, for any reason, the transmitter internal temperature
exceeds the maximum permitted temperature, the output power is automatically reduced to avoid
any fault due to excessive heat.
Figure 5-1. Signal Flow through the Transmitter (LORD Board)
Mismatch protection is also included. If VSWR (Voltage Standing Wave Ratio) is worse than 2:1, the
output power is proportionally reduced to avoid damaging the transmitter.
Seven different multi-section elliptical low-pass filters are inserted between the transmitter's final
output stage and the antenna to reject spurious and harmonic frequencies. The seven filters cover
seven frequency ranges and are automatically switched by PIN diode switches into the circuit
according to the channel selection. The frequency range of these filters are: 1.6 to 2.43 MHz, 2.43 to
3.7 MHz, 3.7 to 5.6 MHz, 5.6 to 8.5 MHz, 8.5 to 13 MHz, 13 to 19.8 MHz and 19.8 to 30 MHz.
The radio has a closed loop automatic level control (ALC) which keeps the output power within the
limits of 125 ±10 Watts.
The automatic gain control loop begins at the output of the harmonic filter near the antenna output
where the output power is sampled (see T6 and its peripheral components in High Power board
schematics). A voltage proportional to the output power is fed back to the power amplifier unit and
enters a comparison amplifier U6 which compares the sample of the output level with the level
determined by the power adjustment word stored in the radio memory and translated to an analog
level by D/A U1104 on the LORD board. For every frequency range, the radio stores the appropriate
power level word. The output of the comparison amplifier is fed to RF attenuator composed of CR54,
CR56. Thus attenuator regulates the input power to the RF amplifier, keeping the output level
constant.
5-2 Cat. No. 6886859J01
Page 41
RF output
1.6 - 30 MHz
IF filter
45.1 MHz
1.05 MHz
DSP
DSM
First injection
Finj1 = 46.7 - 75.1 MHz
step = 8.75 KHz
/2
VCO 1,2,3
Fc1 = 90.4 - 150.2 MHz
step = 17.5 KHz
Synthesizer
Second injection
Finj2 = 46.15 MHz
step = 1.25 KHz
/8
VCO 4
Fc2 = 368.4 MHz
step = 10 KHz
0÷1.25 KHz
10 Hz Res
Figure 5-2. Transmit Path Frequency Conversion Scheme
Cat. No. 6886859J01 5-3
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Intentionally Left Blank
5-4 Cat. No. 6886859J01
Page 43
RX DIRECTION
TX DIRECTION
Audio
amplifier
Anti alias
filter
MIC
AUDIO
SOURCES
Pre-selector
Harmonic
filter
Front-end
attenuator
HF power
amplifier
HIGH-POWER BOARD
Front-end
amplifier
Exciter
amplifier
First mixer
Band pass
filter
Amplifier
Divider
by 2
90.2-150.4 MHz
PLL
First
IF amplifier
45.1 MHz
crystal filter
Bi-directional
IF amplifier
Second
mixer
Band pass
filter
Amplifier
Divider
by 8
352.4-369.2 MHz
PLL
Second
IF amplifier
450 kHz
ceramic filter
Second
IF amplifier
Third mixer
Divider
by 39
16.8 MHz
reference
20 kHz
amplifier
Anti alias
filter
Analog-to-digital
convertor
(ADC)
Digital SSB
modulator
(DSM)
DSP
Audio
circuitry
Audio power
amplifier
AUDIO
OUTPUTS
SPEAKER
SYNTHESIZER #1SYNTHESIZER #2
SYNTHESIZER #3
Figure 5-3. Micom-3 Block Diagram
5-5/5-6
Page 44
5-3. Receiver
The receiver functions as an SSB demodulator for the HF band. It is based on a triple conversion
scheme, which converts a specific 2.7 kHz band of the received spectrum to the input of an ADC
(Analog to Digital Converter), centered at 20 kHz.
The conversion chain is based on analog circuitry that was designed to withstand out-of-band
interference. The frequency resolution of both injections is limited to 1.25 kHz, which is insufficient
to provide the specified 10 Hz resolution. Therefore, the analog section of the conversion chain
provide a coarse tuning only.
After being digitized by the ADC, the received signal is being frequency shifted to the exact frequency
by a digital algorithm in the DSP. This fine tuning process complements the coarse tuning performed
by the analog section of the receiver. After being fine tuned, the signal is SSB demodulated and
filtered according to the radio specifications.
The distribution of the overall frequency resolution between the DSP stage (fine tuning) and the
analog stages (coarse tuning) is common to the receive and the transmit chains.
The RGC (Receiver automatic Gain Control) is an important segment of the receiver. It is based on
analog attenuation stages, distributed along the analog part of the receiver chain, and a digital
algorithm within the DSP. The analog attenuation stages serves as a step-attenuator. Each stage
provides 0 dB attenuation or, when activated, a predefined attenuation. Therefore, the analog section
of the receiver can provide only a coarse gain control.
The DSP controls the activation of these step-attenuator stages, while adding a smoothly varying gain
control by scaling the signal after fine tuning and filtering. The overall performance of the RGC
provides a 100 dB range, starting from -90 dBm.
The DSP processed signal is an audio signal which is amplified to levels up to 5W.
Figure 5-4. Signal Flow through the Receiver
Cat. No. 6886859J01 5-7
Page 45
RF input
0.1 - 30 MHz
First injection
Finj1 = 45.2 - 75.1 MHz
step = 8.75 KHz
/2
VCO 1,2,3
Fc1 = 90.4 - 150.2 MHz
step = 17.5 KHz
Figure 5-5. Receive Path Frequency Conversion Scheme
5-4. Synthesizer
BW=12.1 KHzBW=4.55 KHz
IF filter
45.1 MHz
IF filter
450 KHz
Synthesizer
Second injection
Finj2 = 44.05 - 46.15 MHz
step = 1.25 KHz
/8
VCO 4
Fc2 = 352.4 - 369.2 MHz
step = 10 KHz
430.77 KHz
DSP
0÷3 KHz
10 Hz Res
The synthesizer is designed according the MICOM-3 frequency plan, described in Figure 5-6.
The conversion principles are as follows:
• Receive path: the analog section performs triple frequency conversion; a fourth frequency
conversion is done digitally.
Receive path bandwidth, 10 kHz, is determined by a ceramic filter at a 450 kHz frequency.
• Transmit path: the analog section performs double frequency conversion; a third frequency
conversion is done digitally.
• The conversion frequency resolution of the analog part is 1.25 kHz.
The synthesizer provides two signals to the transmission and reception paths. The first injection signal
covering 45.2 to 75.1 MHz is produced by a PLL (phase locked loop). To enable wide range coverage
while maintaining low noise performance, the 45.2 to 75.1 MHz loop uses three VCOs (Voltage
Controlled Oscillator) in three subranges. The second injection signal is also generated by a PLL IC
covering the 44 to 46 MHz range with one VCO.
In both loops, the VCO frequencies are higher than the output frequencies. The first injection uses a
division by two (U2002) and the second injection uses a division by eight (U2003). The frequency
division decreases spurious level without degrading the lock-in time of the PLL. Frequency division
improves frequency resolution too. Thus, the first injection provides a 8.75 kHz resolution and the
second injection provides a 1.25 kHz resolution.
Both loops use a single reference oscillator at 16.8 MHz. As a result, the overall radio frequency
stability and accuracy are determined by the accuracy and stability of this single reference oscillator.
The reference oscillator is a 1 ppm DTCXO (0.1 ppm OCXO for MICOM-3R). An optional 0.1 ppm
OCXO can be ordered, for enhanced frequency accuracy. The OCXO is a hybrid add-on that is
thermally isolated. It contains a 16.8 MHz crystal oscillator. The temperature of the oscillator is
5-8 Cat. No. 6886859J01
Page 46
controlled to 85°C, using a heat dissipating power transistor and a thermistor that monitors the
temperature and provides feedback to a temperature controller circuitry on board.
16.8 MHz
data
PLL
17.5 KHz
clock
enable
Figure 5-6. Bandwidths and Frequency Plan
frequency range = 90.4 - 150.2 MHz
resolution step = 8.75 KHz
VCO 1
90.4-107 MHz
VCO 2
107-126.5 MHz
VCO 3
126-150.2 MHz
switch_1
switch_2
switch_3
Figure 5-7. First Injection Block Diagram
frequency range = 45.2 - 75.1 MHz
resolution step = 8.75 KHz
DIVIDER
/2
Cat. No. 6886859J01 5-9
Page 47
l
z
data
clock
enab
16.8 MHz
PLL
10 KHz
frequency range = 352.4-369.4 MHz
resolution step = 10 KHz
VCO 4
356.4-368.4 MHz
frequency range = 44.05-46.15 MH
resolution step = 1.25 KHz
DIVIDER
/8
Figure 5-8. Second Injection Block Diagram
5-5. Electronic Boards
The circuitry of the basic MICOM-3 radio is located on three main boards, as follows:
• Low RF and Digital (LORD) board
• High-Power board
• Control Head board (two versions with similar characteristics are used, one for MICOM-3F and
MICOM-3T, and the other for MICOM-3R).
Note
MICOM-3T also uses an Interconnection board for connection to the Control
Head board.
Figure 5-9 identifies the main boards and Table 5-1 indicates the location of the main radio circuits.
Figure 5-9. Identification of Main MICOM-3 Boards
5-10 Cat. No. 6886859J01
Page 48
Table 5-1. Location of Main MICOM-3 Circuits
Circuit
High-Power
Board
LORD
Board
Control
Board
Tx/Rx Power Supply x
Receive Path x x
Excitation x
Amplification and HF Processing x
DSP x
CPU x
Audio Processing x
Loudspeaker and Volume Control x
Keyboard x
Activation x
Interfacing x
Frequency Reference x
Temperature Control x x
Transmit Power Control x x
Digital Voltage Supply x
Main Voltage Switching x
Cat. No. 6886859J01 5-11
Page 49
5-5.1 LORD Board
The LORD board functional block diagram is shown in Figure 5-3. Typical signal levels and
frequencies are given in Figure 5-10.
These signals can be measured with a spectrum analyzer at the test points detailed in this figure. The
location of the mentioned test points is illustrated in Figure 5-11.
Figure 5-10. Receive and Transmit Signals, Frequencies and Gains
5-12 Cat. No. 6886859J01
Page 50
Figure 5-11. Test Points Map
Cat. No. 6886859J01 5-13
Page 51
5-5.2 High-Power Board
See Figure 5-12. The High-Power board comprises the Power Amplifier and the Harmonic Filter
circuits.
Pre-Driver
Amplifier
-6 to -3 dBm
(for full power)
ALC
Circuit
Figure 5-12. High Power Board Functional Block Diagram
5-5.2.1 Power Amplifier (PA)
The PA contains three RF (1.6 to 30 MHz) wide band amplification stages:
• Pre-driver (Q2, Q6)
• Push-pull driver (Q32, Q33)
• Final push-pull power stage (Q35, Q34).
The PA also includes a control circuit which controls the output power level according to the control
signal provided by the ALC D/A (controlled by the microprocessor on the LORD board) and the
temperature at the final push-pull transistor case. This circuit is implemented by three operational
amplifiers (U6) that receive inputs from the ALC D/A and the VSWR detector (the harmonic filter
circuit). It controls an active attenuator (CR54 and CR56), which regulates the RF input to the
amplification stages.
5-14 Cat. No. 6886859J01
Page 52
A two-transistor circuit controls the bias of the driver and final amplifier transistors; as heatsink
temperature increases, the circuit reduces the bias correspondingly.
5-5.2.2 Harmonic Filter
The harmonic filter is used to attenuate the unwanted spurious and harmonics of the transmitted and
received signals. During transmission, the Tx/Rx switch is in transmit state, transferring the RF output
from the PA to the antenna via the harmonic filter. In the receive mode, the Tx/Rx switch is in the
receive state, transferring the received signal from the antenna to the LORD board via the harmonic
filter.
The harmonic filter contains:
• Seven selectable low pass filters.
• Seven electronic switches. Only one switch is on at any time, while the others remain off.
• Tx/Rx electronic switch (includes CR33, CR34, CR35 and CR36).
• Forward/reflected power detector (includes T7, CR4 and CR5).
The filter ranges and switches are listed in Table 5-2.
Table 5-2. Harmonic Filter Bands/Ranges and Controlling Switches
Filter Range (MHz) Switch PIN Diodes
1 1.6 to 2.43 CR40, CR47
2 2.43 to 3.7 CR37, CR44
3 3.7 to 5.6 CR39, CR46
4 5.6 to 8.5 CR42, CR49
5 8.5 to 13 CR41, CR59, CR48, CR59
6 13 to 19.8 CR38, CR45
7 19.8 to 30 CR37, CR44
The harmonic filter contains seven selectable low pass filters, each covering a section of the 1.6 to
30 MHz range. Seven control lines are used to select an appropriate filter according to the operating
frequency. When a control line is pulled down, the corresponding PIN diode switch is turned on and
inserts the corresponding filter in the signal path.
A forward/reflected power detector is inserted between the filters and the antenna. During
transmission it generates two DC signals: one proportional to the forward RF power delivered to the
antenna, and the other proportional to the RF power reflected from the antenna. The signals are sent
to both the exciter and the Control board for controlling the level of the power output as a function of
the following parameters:
• VSWR value. If the VSWR increases above 2:1, the output power is gradually decreased, to
protect the radio from high reflected power.
• Harmonic filter insertion losses. If the harmonic filter insertion loss is too high, the output power
level is decreased.
Cat. No. 6886859J01 5-15
Page 53
Table 5-3. Accessories Connector Pin Functions
Pin Designation Function Direction Notes
1 SPKR- Floating output to external speaker Output 1A
2 STOP SCAN Digital output indication for stop scan
Output
function
3 SPKR+ Floating output to external speaker Output 1A
35 RX AUDIO IN Output from baseband RX path Output
36 AMP FWD Maintain constant power at 500W
Output
transceiver output
37 VP PTT PTT output Output Active low
38 TXD Transmit output (point-to-point protocol to
Output
host/HLC)
39 TXC Transmit output (point-to-point protocol to
Output
host/HLC)
40 TX AUDIO IN Output from baseband TX path Output
41 EXT RX AUDIO(2)+ Audio out from ISB hybrid Output
42 EXT TX AUDIO(2)- Audio out from ISB hybrid Output
43 EXT RX DATA- Baseband output Output
44 EXT RX DATA+ Baseband output Output
0 dBm, 600 Ω
0 dBm, 600 Ω
Cat. No. 6886859J01 5-17
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5-18 Cat. No. 6886859J01
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Chapter 6
Troubleshooting
6-1. Overview
In case of malfunctioning, perform the following steps (refer to the Maintenance section in the
MICOM-3F/3T/3R HF-SSB Transceivers Owner's Guide, publication number: 6886867J01:
1. Use BITE function
2. Refer to the User Troubleshooting Chart
3. Follow the troubleshooting procedures in this section which provide instructions for isolating
faulty boards.
Troubleshooting a board at component level should be performed according to the relevant
schematic diagrams.
6-2. Troubleshooting Charts
This section contains two troubleshooting charts:
• Receiver
• Transmitter.
Cat. No. 6886859J01 6-1
Page 57
Start
Is any sound
heard at the
loudspeaker?
NoYes
Check the
Harmonic filter ranges
Ranges OK
Check coax from High-
Power to LORD board
Reception possible
Check from LORD
input to speaker
Problem
found
Problem
found
Problem
found
Check Harmonic filter
range and its control
lines
Check coax connectors
Check LORD board
Is the input
signal to the
first mixer OK?
Check from Control
Head board to speaker
NoYes
Problem
found
Check first injection
Check 45.1 MHz signal
(IF filter)
Problem
found
Problem
found
Check synthesizer
Check first mixer
Check front-end
pre-selector
A
Figure 6-1.A. Receiver Troubleshooting Flowchart (Sheet 1 of 2)
6-2 Cat. No. 6886859J01
Page 58
A
Check 450 KHz signal
(IF filter)
Check 20 KHz signal
Check A/D
Reception possible
Problem
found
Problem
found
Problem
found
Problem
found
Check synthesizerCheck second injection
Check second mixer
Check 950 KHz
ceramic filter
Check A/D
DC voltage
Check DSP output
signal
Check audio amplifier
Problem
found
Problem
found
Check VCC
Check A
(13.8 V)
+
Check flat cable to
Control Head board
Figure 6-1.B. Receiver Troubleshooting Flowchart (Sheet 2 of 2)
Cat. No. 6886859J01 6-3
Page 59
Start
Is transmission
in AME mode
posible?
Problem persists
Check DSM & DSP
No
Problem
found
Transmit to a
dummy load
Check the Harmonic
filter ranges
Problem in all ranges
Check the 9T, 9R, PA
disable lines
No problem found
Check from High-
Power board to
antenna
Transmission possible
Check from the mic
audio input to DSM
output
Transmission
possible
Problem in
one range
Problem
found
Problem
persists
Problem
persists
Antenna and/or
antenna tuner problem
Check the HF and/or
its control lines
Check the PTT path
from the mic connector
to the Lord board
Check PA power
transistors
Transistors OK
Check PA
Problem
found
Problem
found
Yes
Problem
found
Check from the mic
audio input to Control
Head board output
Problem persists
Check the HP as a
separate unit
Problem
found
Check the flat cable
Problem
found
between the Control
Head and the LORD
board
A
Figure 6-2.A. Transmitter Troubleshooting Flowchart (Sheet 1 of 2)
6-4 Cat. No. 6886859J01
Page 60
A
Check second mixer
output
(45.1 MHz)
Problem persists
Check first mixer
output
(the frequency of the
working channel)
Problem persists
Check LORD board
output to High-Power
board input
Problem
found
Problem
found
Problem
found
Check second injection
synthesizer
Check first injection
synthesizer
Check coax cable
Figure 6-2.B. Transmitter Troubleshooting Flowchart (Sheet 2 of 2)
Cat. No. 6886859J01 6-5
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6-6 Cat. No. 6886859J01
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Chapter 7
Schematic Diagrams,
Layouts and Parts Lists
Note
Spare parts with Part No. starting with 20 or 40 are plant items.