Hytera MD78X Service Manual page 7

Contents
10.7 Parts List ..................................................................................................................................... 201
10.8 Troubleshooting Flow Chart ....................................................................................................... 239
11. UHF2 (450-520MHz 45W) Information .......................................................................................... 245
11.1 Transmitter Circuit ...................................................................................................................... 245
11.1.1 Power Amplifier ................................................................................................................. 245
11.1.2 TX Buffer Amplifier ............................................................................................................ 245
11.1.3 Pre-driver Power Amplifier ................................................................................................ 246
11.1.4 Driver Power Amplifier ...................................................................................................... 246
11.1.5 Final Power Amplifier ........................................................................................................ 246
11.1.6 Antenna Switch ................................................................................................................. 246
11.1.7 Low-pass Filter ................................................................................................................. 246
11.1.8 Directional Coupler ........................................................................................................... 247
11.1.9 Output Power Control ....................................................................................................... 247
11.1.10 Thermal and Over-voltage Protections........................................................................... 247
11.1.11 Pressure Pad Switch ...................................................................................................... 247
11.2 Receiver Circuit .......................................................................................................................... 247
11.2.1 Receiver Front-end ........................................................................................................... 248
11.2.2 Receiver Back-end ........................................................................................................... 249
11.3 Frequency Generation Unit (FGU) ............................................................................................. 249
11.3.1 PLL Synthesizer ................................................................................................................ 249
11.3.2 Reference Oscillator ......................................................................................................... 250
11.3.3 PLL IC ............................................................................................................................... 250
11.3.4 VCO .................................................................................................................................. 251
11.4 PCB View .................................................................................................................................... 252
11.5 Block Diagram ............................................................................................................................ 256
11.6 Schematic Diagram .................................................................................................................... 259
11.7 Parts List ..................................................................................................................................... 273
11.8 Troubleshooting Flow Chart ....................................................................................................... 312
12. UHF3 (350-400MHz 25W) Information .......................................................................................... 318
12.1 Transmitter Circuit ...................................................................................................................... 318
12.1.1 Power Amplifier ................................................................................................................ 318
12.1.2 TX Buffer Amplifier ........................................................................................................... 318
12.1.3 Pre-driver Power Amplifier ............................................................................................... 319
12.1.4 Driver Power Amplifier ...................................................................................................... 319
12.1.5 Final Power Amplifier ....................................................................................................... 319
12.1.6 Antenna Switch ................................................................................................................. 319
12.1.7 Low-pass Filter ................................................................................................................. 319
12.1.8 Directional Coupler ........................................................................................................... 320
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Service Manual