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...

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...

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...

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...

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...

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...

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...

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...

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...

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...