Hytera MD78X Service Manual

UHF1 (400
–
470 MHz)
Contents
i
Contents
1. Product Controls .................................................................................................................................. 1
2. Disassembly and Reassembly ............................................................................................................ 3
2.1 Disassembling the Radio .................................................................................................................. 3
2.2 Reassembling the Radio .................................................................................................................. 4
3. Exploded View and Packing Guide .................................................................................................... 5
3.1 Exploded View .................................................................................................................................. 5
3.2 Packing Guide .................................................................................................................................. 7
4. Specifications and Blind Spot ............................................................................................................ 8
4.1 Specifications .................................................................................................................................... 8
4.2 Blind Spot ....................................................................................................................................... 11
5. Circuit Description ............................................................................................................................. 12
5.1 Front Panel ..................................................................................................................................... 12
5.2 Baseband ........................................................................................................................................ 14
5.2.1 Power Supply Module .......................................................................................................... 14
5.2.2 Control Module ..................................................................................................................... 15
5.2.3 Audio Module ........................................................................................................................ 21
5.2.4 PCB Difference ..................................................................................................................... 22
5.3 RF Section ...................................................................................................................................... 23
5.3.1 Transmitter Circuit ................................................................................................................ 23
5.3.2 Receiver Circuit .................................................................................................................... 26
5.3.3 FGU Circuit ........................................................................................................................... 27
5.4 GPS Circuit Section ........................................................................................................................ 29
6. Troubleshooting Flow Chart ............................................................................................................. 30
6.1 Control Circuit ................................................................................................................................. 30
6.2 GPS Circuit ..................................................................................................................................... 31
6.3 TX Circuit ........................................................................................................................................ 32
6.4 RX Circuit ........................................................................................................................................ 33
6.5 Frequency Generation Unit (FGU) ................................................................................................. 35
7. Interface Definition ............................................................................................................................. 37
7.1 10-Pin Connector ............................................................................................................................ 37
7.2 DB26 Accessory Interface .............................................................................................................. 39
7.3 Other Interfaces .............................................................................................................................. 42
8. Tuning Description ............................................................................................................................. 50
8.1 Required Test Instruments ............................................................................................................. 50
8.2 Tuning Procedures ......................................................................................................................... 50
8.2.1 Tuning the Radio .................................................................................................................. 50
8.2.2 Testing the Radio .................................................................................................................. 53

Hytera MD78X Specifications

General

Brand	Hytera
Model	MD78X
Category	Radio
Language	English