Motorola Gm328 Gm338 Gm398 Detailed 6804112j18 E Manual

							2-1
Section 2
MAINTENANCE
1.0 Introduction
This chapter of the manual describes:
•preventive maintenance
safe handling of CMOS devices
repair procedures and techniques
2.0 Preventive Maintenance
The radios do not require a scheduled preventive maintenance program; however, periodic visual 
inspection and cleaning is recommended.
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 Cleaning
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 the external radio surfaces is a 0.5% solution of a mild 
dishwashing detergent in water. The only factory recommended liquid for cleaning the printed circuit 
boards and their components is isopropyl alcohol (70% by volume).
1.Cleaning External Plastic Surfaces
The detergent-water solution should be applied sparingly with a stiff, non-metallic, short-bris-
tled brush to work all loose dirt away from the radio. A soft, absorbent, lintless cloth or tissue 
should be used 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 servicing or
repair.
CAUTION: The effects of certain chemicals and their vapors can have harmful results on 
certain plastics. Aerosol sprays, tuner cleaners, and other chemicals should be avoided.
! 
						

							2-2Safe Handling of CMOS and LDMOS
2.Cleaning Internal Circuit Boards and Components
Isopropyl alcohol may be applied 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. Upon comple-
tion of 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.
3.0 Safe Handling of CMOS and LDMOS
Complementary metal-oxide semiconductor (CMOS) devices are used in this family of radios. 
CMOS 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. DO NOT attempt to disassemble the radio without first referring to the CMOS CAUTION 
paragraph in the Disassembly and Reassembly section of the manual. 
4.0 General Repair Procedures and Techniques
Parts Replacement and Substitution
When damaged parts are replaced, identical parts should be used. If the identical replacement 
component is not locally available, check the parts list for the proper Motorola part number and 
order the component from the nearest Motorola Communications parts center listed in the “Piece 
Parts” section of this manual.
Rigid Circuit Boards
The family of radios 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 through-plated holes may interconnect multiple layers of the printed circuit. Therefore, care 
should be exercised to avoid pulling the plated circuit out of the hole.
When soldering near the 18-pin and 40-pin connectors: 
avoid accidentally getting solder in the connector. 
be careful not to form solder bridges between the connector pins 
closely examine your work for shorts due to solder bridges.
NOTEAlways use a fresh supply of alcohol and a clean container to prevent contamination by
dissolved material (from previous usage). 
						

							General Repair Procedures and Techniques2-3
Chip Components
Use either the RLN4062 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 370 °C (700 °F), and adjust 
the airflow to a minimum setting. Airflow can vary due to component density.
To remove a chip component: 
1.Use a hot-air hand piece and position the nozzle of the hand piece approximately 0.3 cm (1/
8) above the component to be removed. 
2.Begin applying the hot air. Once the solder reflows, remove the component using a pair of 
tweezers. 
3.Using a solder wick and a soldering iron or a power desoldering station, remove the excess 
solder from the pads.
To replace a chip component using a soldering iron: 
1.Select the appropriate micro-tipped soldering iron and apply fresh solder to one of the solder 
pads. 
2.Using a pair of tweezers, position the new chip component in place while heating the fresh 
solder. 
3.Once solder wicks onto the new component, remove the heat from the solder. 
4.Heat the remaining pad with the soldering iron and apply solder until it wicks to the compo-
nent. If necessary, touch up the first side. All solder joints should be smooth and shiny.
To replace a chip component using hot air:
1.Use the hot-air hand piece and reflow the solder on the solder pads to smooth it. 
2.Apply a drop of solder paste flux to each pad. 
3.Using a pair of tweezers, position the new component in place. 
4.Position the hot-air hand piece approximately 0.3 cm (1/8” ) above the component and begin 
applying heat. 
5.Once the solder wicks to the component, remove the heat and inspect the repair. All joints 
should be smooth and shiny. 
						

							2-4General Repair Procedures and Techniques
Shields
Removing and replacing shields will be done with the R1070 station with the temperature control set 
to approximately 215°C (415°F) [230°C (445°F) maximum].
To remove the shield: 
1.Place the circuit board in the R1070 circuit board holder. 
2.Select the proper heat focus head and attach it to the heater chimney. 
3.Add solder paste flux around the base of the shield. 
4.Position the shield under the heat-focus head. 
5.Lower the vacuum tip and attach it to the shield by turning on the vacuum pump. 
6.Lower the focus head until it is approximately 0.3 cm (1/8”) above the shield. 
7.Turn on the heater and wait until the shield lifts off the circuit board. 
8.Once the shield is off, turn off the heat, grab the part with a pair of tweezers, and turn off the 
vacuum pump. 
9.Remove the circuit board from the R1070 circuit board holder.
To replace the shield: 
1.Add solder to the shield if necessary, using a micro-tipped soldering iron. 
2.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 cir-
cuit board. 
3.Place the circuit board back in the R1070 circuit board holder. 
4.Place the shield on the circuit board using a pair of tweezers. 
5.Position the heat-focus head over the shield and lower it to approximately 0.3 cm (1/8”) above 
the shield. 
6.Turn on the heater and wait for the solder to reflow.
7.Once complete, turn off the heat, raise the heat-focus head and wait approximately one 
minute for the part to cool. 
8.Remove the circuit board and inspect the repair. No cleaning should be necessary. 
						

							Notes For All Schematics and Circuit Boards2-5
5.0 Notes For All Schematics and Circuit Boards
* Component is frequency sensitive. Refer to the Electrical Parts List for value and usage.
1.Unless otherwise stated, resistances are in Ohms (K = 1000), and capacitances are in picofarads 
(pF) or microfarads (µF).
2.DC voltages are measured from point indicated to chassis ground using a Motorola DC 
multimeter or equivalent. Transmitter measurements should be made with a 1.2 µH choke in 
series with the voltage probe to prevent circuit loading.
3.Interconnect Tie Point Legend: 
16_8MHz 16.8MHz Reference Frequency
3V3 Regulated 3.3V Supply Voltage for Voice Storage
5V Regulated 5V Supply Voltage for RF Circuitry
5V Regulated 5V Supply Voltage (Control Head)
5V RF Regulated 5V Supply Voltage for RF Circuitry
5V SOURCE 5V Signal to Switch On Control Head
5VD Regulated 5V Supply Voltage for Digital Circuitry
9V3 Regulated 9.3V Supply Voltage
9V3FLT Filtered 9.3V Supply Voltage
A+ 13.2V Supply Voltage
ADDR µP Address Lines
AN Analog Lines to Analog to Digital Converter
ANALOG INPUT 2 External Keypad Matrix Column Signal
ANALOG INPUT 3 External Keypad Matrix Row Signal
BATTERY VOLTAGE Battery Voltage Sense Line
BL A GREEN Back Light Anode Green
BL A RED Back Light Anode Red
BL GREEN Green Back Light Control
BL K GREEN Back Light Cathode Green
BL K RED Back Light Cathode Red
BL KP Green Green Keypad Back Light Control 
						

							2-6Notes For All Schematics and Circuit Boards
BL KP RED Red Keypad Back Light Control
BL LCD GREEN Green Display Back Light Control
BL LCD RED Red Display Back Light Control
BL RED Red Back Light Control
BOOT CNTRL Bootstrap Mode Enable Signal
BOOT MODE Boot Mode Select
BOOT PWR ON Control Head Switch On Signal
BOOT SCI RX Serial Communication Interface Receive Line
BOOT SCI TX Serial Communication Interface Transmit Line
BOOT VPP Boot Mode Select
BUS+ Bi-directional Serial Communication Line
BWSELECT Signal to select between the Ceramic Filter Pairs
CH ACT Channel Activity Indicator Signal (Fast Squelch)
CH KP ID Control Head Keypad ID (Data) Lines
CH REQUEST Control Head Request from Control Head µP
CLK Clock Signal
CNTLVLTG PA Power Control Voltage
CNTR AUDIO Audio Lines of the Controller
COL x Keypad Matrix Column x
CSX Chip Select Line PCIC / FRACN
DATA Data Signal
DC POWER ON Electronic Switching On or Off of the Radios Voltage Regulators
DISCAUDIO Audio Output Signal from the Receiver IC
ECLK Clock (not used)
EE CS EEPROM Chip Select
EMERGENCY CONTROL Emergency Line to switch on the Radios Voltage Regulators
EXP BD REQ Service Request Line from Expansion Board 
						

							Notes For All Schematics and Circuit Boards2-7
EXP1 CS Expansion Board Chip Select 1
EXP2 CS Expansion Board Chip Select 2
EXT KP COL External Keypad Matrix Column Signal
EXT KP ROW External Keypad Matrix Row Signal
EXT MIC External (from Accessory Connector) Microphone Input
EXT SWB+ External Switched 13.2V Supply Voltage
F1200 Interrupt Line from ASFIC CMP
FECTRL 1 Control Voltage for Front End Filter 
FECTRL 2 Control Voltage for Front End Attenuator Switch
FLASH CS Flash Chip Select
FLASH OE Flash Output Enable
FLAT RX SND Option Board Audio Output Signal
FLAT TX RTN Flat TX Input from Option Board and Accessory Connector
FLT A+ Filtered 13.2 V Supply Voltage
GP x IN General Purpose Input x
GP x IN ACC y General Purpose Input x from Accessory Connector Pin y
GP x IN OUT ACC y General Purpose Input/Output x from Accessory Connector Pin y
GP x OUT General Purpose Output x
GP x OUT ACC y General Purpose Input x from Accessory Connector Pin y
GPIO General Purpose Input Output Lines
HANDSET AUDIO Handset Audio Output
HOOK Hang-up Switch Input
HSIO High Speed Clock In / Data Out
IF First Intermediate Frequency Signal
IGNITION CONTROL Ignition Line to switch on the Radios Voltage Regulators
IN 5V RF REG Supply Voltage for 5V Regulator in RF Section
INT KP COL Internal Keypad Matrix Column Signal 
						

							2-8Notes For All Schematics and Circuit Boards
INT KP ROW Internal Keypad Matrix Row Signal
INT MIC Internal (from Control Head) Microphone Input
INT SWB Internal Switched 13.2V Supply Voltage
INT SWB+ Internal Switched 13.2V Supply Voltage
IRQ Interrupt Request from Control Head
K9V1 9.1V in Transmit Mode
KEYPAD ID Keypad Identification Line
LCD A0 LCD Control / Display Data Select
LCD CS LCD Chip Select
LCD DATA LCD Data Lines
LCD E RD LCD Enable Read
LCD RW WR LCD Read Write Control
LED CNTRL LED Control Lines
LED GREEN Green LED Control
LED RED Red LED Control
LED YELLOW Yellow LED Control
LOCK Lock Detect Signal from Synthesizer
LSIO Low Speed Clock In / Data Out
LVZIF CS LVZIF Chip Select (not used)
MIC Microphone Input
MISO Serial Peripheral Interface Receive Line
MODIN Modulation Signal into the Synthesizer
MOSBIAS 2 PA Bias Voltage for second Stage
MOSBIAS 3 PA Bias Voltage for third Stage
NOISE BLNKR Noise Blanker Enable (Low Band only)
ON OFF CONTROL Service Request Line from Control Head / Manual Switching On
of the Radios Voltage Regulators
ON OFF SENSE (Control Head) On/Off Sense Line to Control Head µP 
						

							Notes For All Schematics and Circuit Boards2-9
ON OFF SENSE (Controller) Service Request Line from Control Head
OPT CS Option Board Chip Select
OPT PTT PTT from Option Board
PA PWR SET ASFIC Output Voltage to set the Transmitter Power
PA SWB Switches Supply Voltage for PA Current Control Circuitry
PA SUPVLTG 13.2 V Supply Voltage of the Transmitter PA
PCIC MOSBIAS 1 PA Bias Voltage for first Stage
PRESC Prescaler Signal from VCO to Synthesizer
PTT IRDEC Microphone PTT Input
PTT IRDECODER Microphone PTT Input
R W Read Write Signal for RAM / Flash
RAM CS RAM Chip Select
RDY Service Request Line from Option Board
REF CS Reference Chip Select (not used)
RESET Reset Line
ROW x Keypad Matrix Row x
RSSI Received Signal Strength Indicator
RX ADAPT Flat TX Path Disable during Transmitter Key-up
RX AUD RTN Option Board Input / Output of Receiver Audio Path
RX FLAT FILTERED AUDIO Flat or Filtered Audio to Accessory Connector
RXIN RF Signal from Antenna Switch into the Receiver
RXINJ RF Signal from the VCO into the Mixer
SCI RX Serial Communication Interface Receive Line
SCI TX Serial Communication Interface Transmit Line
SPI Serial Peripheral Interface Bus
SPKR- Negative Audio PA Speaker Output
SPKR+ Positive Audio PA Speaker Output 
						

							2-10 Notes For All Schematics and Circuit Boards
SQ DET Squelch Detect Signal
SYN µP Clock Signal
TEMP SENSE Temperature Sense Line for LCD
TEMPSENSE Temperature Sense Line from PA to µP
TRB TX/RX VCO Switch Signal
TX AUD RTN Option Board Output to Transmit Audio Path
TX AUD SND Microphone Audio to Option Board
TXINJ RF Signal from the VCO into the Transmitter PA
U DRIVER Supply Voltage for PA Driver
U PREDRIVER Supply Voltage for PA Pre-driver
UNSW 5V Permanent 5V Supply
URX SND Filtered Audio Signal to Option Board
VAG 2.5V Reference Voltage for Analog Circuitry
VCOBIAS 1 Switch Signal from Synthesizer
VCOBIAS 2 Switch Signal from Synthesizer
VCOMOD Modulation Signal into VCO
VCTRL VCO Frequency Control Voltage
VDDA Regulated 5V for Digital Circuitry in RF Section
VOLTAGE SENSE Voltage Sense Line from LCD
VOLUME Volume Pot Output
VOX Voice Operated Transmit Level
VPP Boot Mode Select
VS AUDIOSEL Switch Signal to Enable Option Board Audio Output Signal
VS GAINSEL Voice Storage Gain Select Line
VS INT Voice Storage Interrupt Line
VS MIC Voice Storage Audio Signal into Microphone Path
VS RAC Voice Storage Row Address Clock Signal