Motorola Gp328plus Gp338plus Gp338xls Detailed 6804112j28 G Manual

2-1
Section 2
SERVICE AIDS
1.0 Recommended Test Tools
Table 2-1 lists the tools recommended for working on this family of radios. These tools are also 
available from Motorola.
Table 2-1: Recommended Test Tools
Motorola Part No.DescriptionApplication
6680387A59
6680387A64
6680387A65
0180382A31
Extractor, 2-contact 
Heat controller with safety 
stand or 
Safety stand only
Portable desoldering unit
Removal of discrete surface-mounted devices
6680375A74
0180386A81
0180386A78
0.025 replacement tip, 5/pk...

2-2Recommended Test Tools
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3-1
Section 3
POWER UP SELF-TEST
1.0 Error Codes
Turning on the radio using the ON/OFF volume control starts a self-test routine which checks the 
RAM, ROM checksum, EEPROM hardware and EEPROM checksum. If these checks are 
successfully completed, the radio will generate the Self-Test Pass Tone. Radio emits only “bonk” (300 
Hz) tone if it fails the self-test.
Error CodeExplanationCorrective Action
“RAM TST ERROR”RAM Test FailureRetest radio by turning it off and turning it on again. If 
message...

3-2Error Codes
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4-1
Section 4
CONTROLLER INFORMATION
1.0 Overview
This section provides a detailed theory of operation for the radio and its components.
2.0 Radio Power Distribution
Figure 4-1 illustrates the DC distribution throughout the radio board.  A 7.5V battery (BATT 7.5V) 
supplies power directly to the electronic ON/OFFcontrol as UNSWB+.  When the radio is turned on, 
MECH_SWB+ (ON/OFF volume control) will trigger the electronic ON/OFFcontrol(momentary-on 
path), then SWB+ is distributed  as shown in Figure...

4-2Controller Board
When  low battery level is detected by the microprocessor through both conditions above, it will store 
the radio personality data to EEPROM before turning off. 
3.0 Controller Board
3.1 General
The controller board is the central interface between the various subsytems of the radio. It is 
separated into digital and audio architectures. The digital portion consists of a special Motorola 
microcontroller (HC11FL0). The audio power amplifier (Audio PA) and audio/signalling/filter/...

Controller Board4-3
3.2 Digital Architecture
MCU configuration 
There is one common MCU architecture for low-tier as well as for the high-tier products. It covers the 
Conventional and Trunking portables. An open architecture system with the new HC11FL0 as the 
processor is used. Combinations of different size RAM, ROM and EEPROM are available for various 
application software.
Real Time Clock (RTC) 
This radio supports Real Time Clock (RTC) module for  purposes of Message Time Stamping and 
Time...

4-4Controller Board
ModB/Vstby Supply 
Under various conditions, the supply to the ModB/Vstby would vary.  Table 4-1 shows these 
conditions and circuits in operation.
Table 4-1: ModB/Vstby Supply Modes
ConditionCircuit Operation
Radio OnVdd supply voltage via CR411
Radio Off• Vdd turned off
• Q416 gate is pulled low by R462
• Q416 is switched on
• U410 supplies 3.2V to ModB/Vstby
Primary battery removed• Vdd turned off
• Q416 gate is pulled low by R462
• Q416 is switched on
• Li Ion battery provides...

Controller Board4-5
3.3 Keypad
The LED_EN setting is set by the codeplug. When the value is set to high, the LED will not light up 
during power up and vice versa. 
U602 is a comparator that will compare the voltage  when  any one of the keypad row or  keypad 
column keys is being pressed. Therefore when a key is being pressed, it will send a message to the 
microprocessor through the output (KEY_INT) telling it that a key has been pressed. The 
microprocessor will then sample the Analog to Digital...

4-6Controller Board
3.4 Troubleshooting Chart
Figure 4-5: Keypad Board Troubleshooting Chart
Display
Keypad 
LED
End
Disconnect and 
reconnect 18-pin 
flex
Disconnect and 
reconnect 40-pin 
flex
ONOFF
OFF ONIF STILL OFF