Motorola Vhf 136 174 Mhz Uhf 435 480 Mhz 6881096c38 Manual

							Chapter 2 Maintenance
2.1 Introduction
This chapter provides details about the following:
• Preventive Maintenance
• Safe Handling of CMOS and LDMOS Devices
• General Repair Procedures and Techniques
• Disassembling and Reassembling the Radio
2.2 Preventive Maintenance
The radio does not require a scheduled preventive maintenance program; however, periodic visual 
inspection and cleaning is recommended.
2.2.1 Inspection
Check that the external surfaces of the radio are clean, and that all external controls and switches 
are functional. It is not recommended to inspect the interior electronic circuitry.
2.2.2 Cleaning Procedures
The following procedures describe the recommended cleaning agents and the methods to be used 
when cleaning the external and internal surfaces of the radio. External surfaces include the front 
cover, housing assembly and battery case. These surfaces should be cleaned whenever a periodic 
visual inspection reveals the presence of smudges, grease, and/or grime.
The only recommended agent for cleaning external radio surfaces is a 0.5% solution of a mild 
dishwashing detergent in water. The only factory recommended liquid for cleaning printed circuit 
boards and their components is isopropyl alcohol (70% by volume).
2.2.2.1  Cleaning External Plastic Surfaces
Apply the 0.5% detergent-water solution sparingly with a stiff, non-metallic, short-bristled brush to 
work all loose dirt away from the radio. Use a soft, absorbent, lintless cloth or tissue to remove the 
solution and dry the radio. Make sure that no water remains entrapped near the connectors, cracks, 
or crevices.
NOTEInternal surfaces should be cleaned only when the radio is disassembled for service or
repair.
CAUTION:The effects of certain chemicals and their vapors can have harmful results on certain
plastics. Avoid using aerosol sprays, tuner cleaners, and other chemicals. 
						

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2-2Maintenance: Safe Handling of CMOS and LDMOS Devices
2.2.2.2  Cleaning Internal Circuit Boards and Components
Apply Isopropyl alcohol (70%) with a stiff, non-metallic, short-bristled brush to dislodge embedded or 
caked materials located in hard-to-reach areas. The brush stroke should direct the dislodged 
material out and away from the inside of the radio. Make sure that controls or tunable components 
are not soaked with alcohol. Do not use high-pressure air to hasten the drying process since this 
could cause the liquid to collect in unwanted places. After completing the cleaning process, use a 
soft, absorbent, lintless cloth to dry the area. Do not brush or apply any isopropyl alcohol to the 
frame, front cover, or back cover.
2.3 Safe Handling of CMOS and LDMOS Devices
Complementary metal-oxide semiconductor (CMOS) devices are used in this family of radios, and 
are 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. DO NOT attempt to disassemble the radio without first referring to the following 
CAUTION statement. 
NOTEAlways use a fresh supply of alcohol and a clean container to prevent contamination
by dissolved material (from previous usage).
CAUTION:This radio contains static-sensitive devices. Do not open the radio unless you are
properly grounded. Take the following precautions when working on this unit:
• Store and transport all CMOS devices in conductive material so that all exposed leads 
are shorted together. Do not insert CMOS devices into conventional plastic “snow” 
trays used for storage and transportation of other semiconductor devices.
• Ground the working surface of the service bench to protect the CMOS device. We 
recommend using the Motorola Static Protection Assembly (part number 
0180386A82), which includes a wrist strap, two ground cords, a table mat, and a floor 
mat.
• Wear a conductive wrist strap in series with a 100k resistor to ground. (Replacement 
wrist straps that connect to the bench top covering are Motorola part number RSX-
4015.)
• Do not wear nylon clothing while handling CMOS devices.
• Do not insert or remove CMOS devices with power applied. Check all power supplies 
used for testing CMOS devices to be certain that there are no voltage transients 
present.
• When straightening CMOS pins, provide ground straps for the apparatus used.
• When soldering, use a grounded soldering iron.
• 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. 
						

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Maintenance: Repair Procedures and Techniques — General 2-3
2.4 Repair Procedures and Techniques — General
2.4.1 Parts Replacement and Substitution
When damaged parts are replaced, identical parts should be used. If the identical replacement part 
is not locally available, check the parts list for the proper Motorola part number and order the part 
from the nearest Motorola Communications parts center listed in the Replacement Parts Ordering 
section of this manual.
2.4.2 Rigid Circuit Boards
This radio uses bonded, multi-layer, printed circuit boards. Since the inner layers are not accessible, 
some special considerations are required when soldering and unsoldering components. The printed-
through holes may interconnect multiple layers of the printed circuit. Therefore, exercise care to 
avoid pulling the plated circuit out of the hole.
When soldering near the 20-pin and 40-pin connectors: 
• Avoid accidentally getting solder in the connector. 
• Be careful not to form solder bridges between the connector pins. 
• Examine your work closely for shorts due to solder bridges.
2.4.3 Flexible Circuits
The flexible circuits are made from a different material than the rigid boards, and require different 
soldering techniques. Excessive prolonged heat on a flexible circuit can damage the material. 
Therefore, avoid excessive heat and excessive bending. 
For parts replacement, use the ST-1087 Temperature-Controlled Solder Station with a 600-700 
degree F tip, and use small diameter solder such as ST-633. The smaller size solder will melt faster 
and require less heat to be applied to the circuit.
To replace a component on a flexible circuit: 
1. Grasp with seizers (hemostats) the edge of the flexible circuit near the part to be removed. 
2. Pull gently.
3. Apply the tip of the soldering iron to the component connections while pulling with the seizers.
2.4.4 Chip Components
Use either the RLN-4062 Hot-Air Repair Station or the Motorola 0180381B45 Repair Station for chip 
component replacement. When using the 0180381B45 Repair Station, select the TJ-65 mini-
thermojet hand piece. On either unit, adjust the temperature control to 700 degrees F. (370 degrees 
C), and adjust the airflow to a minimum setting. Airflow can vary due to component density.
• To remove a chip component, select a hot-air hand piece and position the nozzle of the hand 
piece approximately 1/8” above the component to be removed. Begin applying hot air. Once the 
solder reflows, remove the component using a pair of tweezers. Using solder wick and a 
soldering iron or a power desoldering station, remove the excess solder from the pads.
NOTEDo not attempt to puddle-out components. Prolonged application of heat may dam-
age the flexible circuit. 
						

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2-4Maintenance: Disassembling and Reassembling the Radio — General
• To replace a chip component using a soldering iron, select the appropriate micro-tipped 
soldering iron and apply fresh solder to one of the solder pads. Using a pair of tweezers, 
position the new chip component in place while heating the fresh solder. Once solder wicks 
onto the new component, remove the heat from the solder. Heat the remaining pad with the 
soldering iron and apply solder until it wicks to the component. If necessary, touch up the first 
side. All solder joints should be smooth and shiny.
• To replace a chip component using hot air, select the hot-air hand piece and reflow the solder 
on the solder pads to smooth it. Apply a drop of solder paste flux to each pad. using a pair of 
tweezers, position the new component in place. Position the hot-air hand piece approximately 
1/8” above the component and begin applying heat. Once the solder wicks to the component, 
remove the heat and inspect the repair. All joints should be smooth and shiny.
2.4.5 Shields
Removing and replacing shields will be done with the R-1070 station with the temperature control set 
to approximately 415°F (215°C); 445°F (230°C) max.
• To remove the shield, place the circuit board in the R-1070’s holder. Select the proper heat 
focus head and attach it to the heater chimney. Add solder paste flux around the base of the 
shield. Position the shield under the heat-focus head. Lower the vacuum tip and attach it to the 
shield by turning on the vacuum pump. Lower the focus head until it is approximately 1/8” 
(0.3cm) above the shield. Turn on the heater and wait until the shield lifts off the circuit board. 
Once the shield is off, turn off the heat, grab the part with a pair of tweezers, and turn off the 
vacuum pump. Remove the circuit board from the R-1070’s circuit board holder.
• To replace the shield, add solder to the shield if necessary, using a micro-tipped soldering iron. 
Next, rub the soldering iron tip along the edge of the shield to smooth out any excess solder. 
Use solder wick and a soldering iron to remove excess solder from the solder pads on the 
circuit board. Place the circuit board back in the R1070’s circuit board holder. Place the shield 
on the circuit board using a pair of tweezers. Position the heat-focus head over the shield and 
lower it to approximately 1/8” above the shield. Turn on the heater and wait for the solder to 
reflow.
Once complete, turn off the heat, raise the heat-focus head and wait approximately one minute 
for the part to cool. Remove the circuit board and inspect the repair. No cleaning should be 
necessary.
2.5 Disassembling and Reassembling the Radio — General
Since these radios may be disassembled and reassembled with the use of only four (board to 
casting) screws, it is important to pay particular attention to the snaps and tabs, and how parts align 
with each other.
The following tools are required for disassembling the radio:
• Phillips screwdriver
• 4mm socket wrench
• Flathead screwdriver
If a unit requires more complete testing or service than is customarily performed at the basic level, 
send this unit to a Motorola Authorized Service Center. 
						

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Maintenance: Radio Disassembly — Detailed 2-5
2.6 Radio Disassembly — Detailed
2.6.1 Front Cover from Chassis Disassembly
1. Turn off the radio.
2. Remove the battery:
a. Slide the battery clasp away from the radio (See Figure 2-1).
b. Slide battery down and away from radio.
3. Remove the antenna.
4. Pull the On/Off Volume knob off of its shaft.
5. Remove the two screws at the back of the rear chassis (See Figure 2-2). Figure 2-1.  
Figure 2-2.  
Insert flathead
to remove chassis. screwdriver here 
						

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2-6Maintenance: Radio Disassembly — Detailed
6. Insert a small flathead screwdriver at the bottom of the radio, between the chassis and 
housing (location marked in Figure 2-2), and lift the chassis gently. Be careful not to damage 
the housing or the O-ring underneath.
7. Lift the rear chassis away from the front cover (See Figure 2-3). Be careful not to damage the 
speaker wire underneath.
8. Slide the rear chassis downwards, and away from the front cover.
9. Remove the speaker connector, which connects between RF Board and the internal speaker 
on the front cover (See Figure 2-4). Figure 2-3.  
Figure 2-4.  
Speaker
Connector
Speaker
Connector 
						

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Maintenance: Radio Disassembly — Detailed 2-7
2.6.2 Control Board Disassembly
1. Remove the screws which hold the control board to the RF board.
2. Remove the control board which is connected to the RF board through a board-to-board 
connector (See Figure 2-5).
2.6.3 RF Board Disassembly
1. Remove the screws and the stud which hold the RF board to the rear diecast with the Phillips 
head screwdriver and socket wrench respectively.
2. Gently remove the RF board from rear diecast. Then, completely disassembled radio is 
shown in Figure 2-6.Figure 2-5.  
Figure 2-6.  
Board-to-Board
Connector 
						

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2-8Maintenance: Radio Disassembly — Detailed
Note:The Control and RF boards are mounted with cross recess screws meeting the Phil-
lips Cross Slot number 1 standard. Using a Phillips 0 will damage the screw recesses 
as will a poorly fitting Phillips 1 screwdriver. One example of a correct fitting screw-
driver is manufactured by PB Baumann (http://www.pbtools.ch/index_e.html) and is 
available from many electronic tool dealers. The PB Baumann item number is 121/1-
70. Other high quality manufacturers pruducts meeting the Phillips 1 standard are 
also acceptable. 
						

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Maintenance: Radio Reassembly — Detailed 2-9
2.7 Radio Reassembly — Detailed
2.7.1 RF Board Reassembly
1. Place the RF board on the rear diecast.
2. Tighten the screws and the stud.
2.7.2 Control Board Reassembly
1. Place the control board on the RF board.
2. Connect the control board to the RF board by pressing it firmly downwards at the board-to-
board connector (See Figure 2-7).
3. Tighten the screws using a screwdriver to hold the control board in place.
2.7.3 Chassis and Front Cover Reassembly
1. Assemble the front keypad into the front cover (See Figure 2-8).
2. Press the keypad firmly to the front cover to make sure the keypad ribs are fully flush to 
groove on front cover.
3. Place the front cover over the tabs on the rear diecast.Figure 2-7.  
Figure 2-8.  
Board-to-Board
Connector 
						

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2-10Maintenance: Radio Reassembly — Detailed
4. Insert the On/Off shaft and antenna nut into the front cover opening.
5. Lower the front cover closed to the diecase bottom edges.
6. Connect the RF Board to the internal speaker on the front cover with the speaker connector 
(See Figure 2-9).
7. Snap the front cover firmly into place on the rear diecast (See Figure 2-10). Figure 2-9.  
Figure 2-10.  
Speaker
Connector