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AE/LZB 119 1902 R1A
18
LCD NEGATIVE BIAS GENERATOR
A 96 kHz, 5V p-p square wave from HILLARY D701-
57 is rectified and inverted to a negative supply voltage by
C922, V909 and C923. This negative voltage is controlled
to the LCD by V910 to vary the display contrast.
Thermistor R604 is monitored via the A/D input to
DEBBIE. As the temperature varies, the bias is varied using
4 binary output lines from HILLARY:
• •
LCD_BIAS 0
• •
LCD_BIAS 1
• •
LCD_BIAS 2
• •
LCD_BIAS 3
SERVICE
Due to the state of the art manufacturing processes and
the complexity of the circuits designed into the radio, field
test and repair to the hardware is very limited. It is not
practical to service the main circuit board in this radio to
component level. Technicians servicing this radio should be
concerned with isolating the problem to hardware or
software. Software errors or problems are usually corrected
by reloading the personality, flash, etc.
It is recommended that all hardware repairs to the main
circuit board be done at Ericsson Inc. in Lynchburg,
VA.
On occasion it may become necessary to perform
certain hardware repairs in the field. Therefore, Service
Parts will provide replacement parts for the following
hardware items:
• Flex Assembly • Keypad
• Loudspeaker • Vol/Grp Switch Module
• Battery Connector • Rx RF Filter (Z400)
• PA Module • Rx RF Filter (Z401)
• DSP Module • Fuse
• Main PCB Assembly
Keeping in mind the service philosophy for this
product, it is not the intent of this service section to provide
detailed instructions for testing and troubleshooting the
portable radio. This section will provide the following:
• Programming instructions (Personality, Flash and
Equipment Setup)
• Basic Troubleshooting (determine if problem is
hardware or software)
• Error Codes
• Dissassembly
EQUIPMENT REQUIRED
Equipment Description Part Number
1. ProGrammer
TM
Programming
Software
AE/LZY 213 7641
2. Programming Interface Module
With Power Supply
(19B800850P2)
TQ-3370
(19D438367G2)
3. Programming Cable
TQ-3368
(19B801971P3)
4. RS-232 Cable
19B235027P1
5. Test Box
TQ-0609A
6. Test Cable
19B801971P6
7. Radio Test Set
customer supplied
8. IBM PC/XT/AT/286/386/486 or
any true compatible with MS-
DOS version 3.3 or later.
customer supplied
PROGRAMMING
Personality Programming
The ProGrammer PC Programmer (AE/LZY 213 7641)
Version
1
or later is used to edit, read or write the
personality to the radio. A
personality
is simply a computer
file generated (created) by the user of the program. The
computer file (or personality) is downloaded into the radio
and contains data that will direct certain operating
characteristics of the radio unit.
The PC Programming software communicates with the
radio through the TQ-3370 programming box (item 2 in the
equipment list). Figure 7 provides a diagram of the
Equipment Setup required to PC Program the radio.
The CONV-1 PC Programmer (TQ-3367) Version
12
or later is used to program conventional only radios.
NOTE