Technical Manual
Table Of Contents
- Vocoder and Controller Boards Detailed Theory of Operation
- Introduction to This Section
- General
- Vocoder Board
- Controller Board
- Switching Regulator
- RX Signal Path
- TX Signal Path
- Controller Bootstrap and Asynchronous Buses
- Vocoder Bootstrap
- SPI Bus Interface
- Universal Connector and Option Selects
- Keypad and Display Module
- Controls and Control Top Flex
- Controller Memory Map
- Vocoder Memory Map
- MCU System Clock
- DSP System Clock
- Radio Power-Up/ Power-Down Sequence
- Notes
- Secure Modules
- Disassembly/Reassembly Procedures
- Troubleshooting Procedures
- Troubleshooting Charts
- Troubleshooting Waveforms
- Troubleshooting Diagrams
10-36
Chart 37. VHF/UHF Only, VCO Crossover Frequency Tune
VCO-VEE Crossover
Freq. Tune Procedure
Program Radio to
Low Band Edge
136 MHz (VHF)
403 MHz (UHF1)
450 MHz (UHF2)
Is
VCTRL (TP5)
>3.0V?
YES
MAEPF-23274-A
NO
Program Radio to
High Band Edge
178 MHz (VHF)
470 MHz (UHF1)
520 MHz (UHF2)
Is
VCTRL
>11.0V?
Program the New
Crossover Frequency
into the Codeplug
Is
VCTRL
2.5V to 3.5V?
Replace C240 or C223
*
Use Up/Down Buttons
to Tune Crossover
Frequency w/RSS
VHF
3.0
2.7
UHF1
2.7
2.4
UHF2
2.7
2.7
C240(RX)
C223(TX)
Replace C240 or C223
*
VHF
2.4
2.0
UHF1
2.0
1.6
UHF2
2.0
2.0
C240(RX)
C223(TX)
Enable -VEEE
Crossover Point
Tune Mode w/RSS
YES
NO
NO
YES
A complete part description and
Motorola part number for ordering
is located in the service manual.
*