Hytera MD78X User manual

DIGITAL MOBILE RADIO
SERVICE MANUAL

Preface
This manual describes the information related to the product repair. It is intended for use by qualified
technicians only. To repair the product properly, please read this manual carefully before repairing.
This manual is applicable to the following product:
MD78X Digital Mobile Radio (X may indicate 2, 5, 6 or 8)
MD78XG Digital Mobile Radio (X may indicate 2, 5, 6 or 8)
UHF1 (400–470 MHz)
UHF2 (450–520 MHz)
UHF3 (350–400 MHz)
UHF5 (806–941 MHz)
VHF (136–174 MHz)

Copyright Information
Hytera is the trademark or registered trademark of Hytera Communications Corporation Limited (the
Company) in PRC and/or other countries or areas. The Company retains the ownership of its trademarks
and product names. All other trademarks and/or product names that may be used in this manual are
properties of their respective owners.
The product described in this manual may include the Company’s computer programs stored in memory
or other media. Laws in PRC and/or other countries or areas protect the exclusive rights of the Company
with respect to its computer programs. The purchase of this product shall not be deemed to grant, either
directly or by implication, any rights to the purchaser regarding the Company’s computer programs. Any
of the Company’s computer programs may not be copied, modified, distributed, decompiled, or
reverse-engineered in any manner without the prior written consent of the Company.
The AMBE+2TM voice coding technology embodied in this product is protected by intellectual property
rights including patent rights, copyrights and trade secrets of Digital Voice Systems, Inc. This voice
coding technology is licensed solely for use within this product. The user of this technology is explicitly
prohibited from attempting to decompile, reverse engineer, or disassemble the Object Code or in any
other way convert the Object Code into a human-readable format.
U.S. Patent No: #6,912,495 B2, #6,199,037 B1, #5,870,405, #5,826,222, #5,754,974, #5,701,390,
#5,715,365, #5,649,050, #5,630,011, #5,581,656, #5,517,511, #5,491,772, #5,247,579, #5,226,084 and
#5,195,166.
Disclaimer
The Company endeavors to achieve the accuracy and completeness of this manual, but no warranty of
accuracy or reliability is given. All the specifications and designs are subject to change without notice
due to continuous technology development. No part of this manual may be copied, modified, translated,
or distributed in any manner without the express written permission of us.
We do not guarantee, for any particular purpose, the accuracy, validity, timeliness, legitimacy or
completeness of the Third Party products and contents involved in this manual.
If you have any suggestions or would like to learn more details, please visit our website at:
http://www.hytera.com.

Documentation Information
Conventions
Icon Conventions
Icon Description
Tip Indicates information that can help you make better use of your product.
Note Indicates references that can further describe the related topics.
Caution Indicates situations that could cause data loss or equipment damage.
Warning Indicates situations that could cause minor personal injury.
Danger Indicates situations that could cause major personal injury or even death.
Notation Conventions
Notation Description
“ ”
The quotation marks enclose the name of a software interface element. For
example, click “OK”.
Bold
The text in boldface denotes the name of a hardware button. For example, press
the PTT key.
->
The symbol directs you to access a multi-level menu. For example, to select “New”
from the “File” menu, we will describe it as follows: “File -> New”.
Revision History
Version Release Date Description
R7.0 04-2016
Updated the description about UHF1, UHF2, UHF3,
UHF5, and VHF.
R5.0 06-2013 Added the description about UHF5.
R3.5 10-2011 Added the description about VHF, UHF2, and UHF3.
R1.0 10-2010 Initial release.

UHF1 (400–470 MHz)

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

Contents
UHF1 (400
–
470 MHz)
ii
9. PCB View............................................................................................................................................. 55
10. Block Diagram .................................................................................................................................. 59
11. Schematic Diagram.......................................................................................................................... 62
12. Parts List ........................................................................................................................................... 76
12.1 Front Panel ................................................................................................................................... 76
12.2 GPS Circuit ................................................................................................................................... 77
12.3 Main Board (25 W) ....................................................................................................................... 77
12.4 Main Board (45 W) ....................................................................................................................... 90

UHF1 (400
–
470 MHz)
Product Controls
1
1. Product Controls
Front Panel
No. Part Name No. Part Name
1
Volume Control/Group Call Selector
Knob
8 Up Key
2 LED Indicator 9 Down Key
3 LCD Display 10 Speaker
4 OK/Menu Key 11 Redial/Answer/Call Key
5 Back/Group Call Management Key 12 Programmable Keys
6 Dial-back/End/Home Screen Key 13 Microphone Connector
7 Power On/Off Key 14 Microphone Installation Index
Note
The above-mentioned product control is based on the mobile radio in the trunking mode. In the
conventional mode, No. 1 serves as Volume Control / Channel Selector Knob, and No. 6 & No.11
serve as the Programmable Keys.

Product Controls
UHF1 (400
–
470 MHz)
2
Rear Panel
No. Part Name No. Part Name
1 RF Antenna Connector 3 Accessory Connector
2 Power Inlet 4 GPS Antenna Connector
Note
The GPS antenna interface is only available for MD78XG.

UHF1 (400
–
470 MHz)
Disassembly and Reassembly
3
2. Disassembly and Reassembly
2.1 Disassembling the Radio
Step 1 Turn off the radio and remove the power cord, and loosen the two screws to remove the radio.
Step 2 Remove the antenna.
Step 3 Loosen the three screws to remove the front panel. Then remove the FFC.
Step 4 Detach the volume control knob and loosen the four screws. Then remove the PCB from the
control panel.
Step 5 Undo the clips on both sides of the radio, and then remove the rear cover.

Disassembly and Reassembly
UHF1 (400
–
470 MHz)
4
Step 6 Loosen the eleven screws to remove the upper shield cover.
Step 7 Loosen the screw fixing the antenna connector and two screws fixing the PA module. Then take
the PCB out.
2.2 Reassembling the Radio
To reassemble the radio, perform the above steps in a reverse way.

UHF1 (400
–
470 MHz)
Exploded View and Packing Guide
5
3. Exploded View and Packing Guide
3.1 Exploded View
Part list:
No. Part No. Description Qty. No. Part No. Description Qty.
1
6300109000000
Aluminum chassis
1
27
6100334000000
O-ring for encoder switch
1
2
7500358000000
Heat sink pad
1
28
4399030000020
Rotary switch
1
3
6100492101000
Waterproof ring for front
case
1
29
41078001000J0
PCB for control panel
1
4
4210090000200
Signal cable
1
30
6100533101000
Waterproof ring for
aluminum chassis
1
5
5208010100010
Connector (male)
1
31
6300126000000
Upper cover of the
aluminum chassis
1
6
6001079000000
Light-guide plate for keys
1
32
7103015000000
Machine screw
11
7
7300048000000
Metal dome
1
33
6001080000000
Plastic upper cover
1
8
6100408001000
Waterproof ring for
microphone jack
1
34
6100496000000
Conductive silicone
rubber for main board
1
9
6100488000000
P+R front panel keys
1
35
7103008000400
Machine screw
2
10
6201893000000
Speaker fixing sheet
1
36
7500272000000
Heat sink pad
2
11
7102606021000
Self-tapping screw
6
37
/
Semi-finished PA with
1

Exploded View and Packing Guide
UHF1 (400
–
470 MHz)
6
No. Part No. Description Qty. No. Part No. Description Qty.
heat sink pad
12
4210080000700
Speaker cable (with 2-Pin
plug)
1
38
3414999000020
PNP transistor
1
13
5001210000390
Speaker
1
39
/
Main PCB
1
14
7400297000000
Speaker felt
1
40
6100532100000
D_SUB waterproof ring
1
15
7102505000110
Machine screw
3
41
5208026100000
Jack
1
16
6001076000010
Front case for control
panel
1
42
6100530100000
Waterproof ring for power
socket
1
17
860P580600100
Logo
1
43
5205002100110
Power socket (male)
1
18
6201739000000
Inner lining for knob
1
44
3103994770150
Electrolytic capacitor
1
19
6000876000000
Encoder knob
1
45
7212002500000
Nut
1
20
6100493000000
Power on/off key
1
46
6100531100000
Waterproof ring for
antenna connector
1
21
6100404000000
Emergency key
1
47
4401000009000
BNC RF connector
1
22
7500344000000
PORON pad
1
48
6100494000000
GPS soft stopple
1
23
5130000000040
TFT LCD 2.0" TFT
1
49
7500159000100
Thermal conductive
silicone rubber
2
24
6001078000000
LCD bracket
1
50
7500357000000
Heat sink pad
1
25
5202002100270
Board-to-wire connector
1
A
6100574100000
O_ring
11
26
7207003700000
Nut
1
B
7500344000000
PORON pad
1
Note
Parts that are not marked with Part No. may vary with the radio frequency band.

UHF1 (400
–
470 MHz)
Exploded View and Packing Guide
7
3.2 Packing Guide

Specifications and Blind Spot
UHF1 (400
–
470 MHz)
8
4. Specifications and Blind Spot
4.1 Specifications
General
Frequency Range 400–470 MHz
Channel Capacity 1024
Group Capacity 64 (each with a maximum of 16 channels)
Channel Spacing 12.5 kHz / 20 kHz / 25 kHz
Operating Voltage 13.6V±15% DC
Current Drain
 Standby: <0.6 A
 Receive: <2.0 A
 Transmit: 5 W: <5 A; 25 W: <8 A, 45 W: <12 A
Frequency Stability ±1.5 ppm
Antenna Impedance 50 Ω
Dimensions (H×W×D) 60 mm × 174 mm × 200 mm (2.4 inch × 6.9 inch × 7.9 inch)
Weight 1.7 kg (3.75 lbs)
LCD Display 220*176 pixels, 262000 colors, 2.0-inch, 4 rows
Transmitter
Power Output
 Low: 5–25 W
 High: 5–45 W
Conducted/Radiated
Emission
 -36 dBm <1 GHz
 -30 dBm >1 GHz
FM Modulation
 11K0F3E@12.5 kHz
 14K0F3E@20 kHz
 16K0F3E@25 kHz
4FSK Digital Modulation  12.5 kHz (data only): 7K60FXD

UHF1 (400
–
470 MHz)
Specifications and Blind Spot
9
 12.5 kHz (data and voice): 7K60FXW
Modulation Limit
 ±2.5 kHz@12.5 kHz
 ±4.0 kHz@20 kHz
 ±5.0 kHz@25 kHz
FM Hum and Noise
 40 dB@12.5 kHz
 43 dB@20 kHz
 45 dB@25 kHz
Adjacent Channel Power
 60 dB@12.5 kHz
 70 dB@20/25 kHz
Audio Response +1 dB to -3 dB
Audio Distortion ≤3%
Digital Vocoder Type AMBE++ or SELP
Digital Protocol ETSI-TS102 361-1, -2, -3
Receiver
Sensitivity
Analog:
 0.3 μV (12 dB SINAD)
 0.22 μV (Typical) (12 dB SINAD)
 0.4 μV (20 dB SINAD)
Digital:
 0.3 μV /BER5%
Adjacent Channel
Selectivity
 TIA-603: 65 dB@12.5 kHz/75 dB@20/25 kHz
 ETSI: 60 dB@12.5 kHz/75 dB@20/25 kHz
Intermodulation
 TIA-603: 75 dB@12.5/20/25 kHz
 ETSI: 70 dB@12.5/20/25 kHz
Spurious Response
Rejection
 TIA-603: 75 dB@12.5/20/25 kHz
 ETSI: 70 dB@12.5/20/25 kHz
Blocking
 TIA-603: 90 dB
 ETSI: 84 dB

Specifications and Blind Spot
UHF1 (400
–
470 MHz)
10
Hum and Noise
 40 dB@12.5 kHz
 43 dB@20 kHz
 45 dB@25 kHz
Rated Audio Power
 Internal (20 Ω load): 3 W
 External (8 Ω load): 7.5 W
Max. Audio Power
 Internal (20 Ω load): 8 W
 External (8 Ω load): 20 W
Rated Audio Distortion ≤ 3%
Audio Response +1 dB to -3 dB
Conducted Spurious
Emission < -57 dBm
Environment
Operating Temperature -30℃ to +60℃
Storage Temperature -40℃ to +85℃
ESD
IEC 61000-4-2 (level4)
±8 kV (contact)
±15 kV (air)
American Military Standard MIL-STD-810 C/D/E/F/G
Dust & Water Protection IP54
Humidity Per MIL-STD-810 C/D/E/F/G Standards
Shock and Vibration Per MIL-STD-810 C/D/E/F/G Standards
GPS (for MD780XG only)
Accuracy specs are for long-term tracking (95th percentile values>5 satellites visible at a nominal
-130dBm signal strength).
TTFF (Time To First Fix) < 60s

UHF1 (400
–
470 MHz)
Specifications and Blind Spot
11
Cold Start
TTFF (Time To First Fix)
Hot Start <10s
Horizontal Accuracy <10 m
Note
All Specifications are tested according to applicable standards, and subject to change without notice
due to continuous development.
4.2 Blind Spot
No. Blind Spot (MHz) No. Blind Spot (MHz)
1 403.2 5 414
2 422.4 6 432
3 441.6 7 450
4 460.8 8 468

Circuit Description
UHF1 (400
–
470 MHz)
12
5. Circuit Description
5.1 Front Panel
Front panel includes components such as power supply, keys, LCD, LED indicators, backlight, MMC
interface and volume control knob. The function diagram is shown below.
CONTROL HEAD
BACK LIGHT&
SIGNAL LIGHT
BL_LED
RX_LED
TX_LED
U1 \RESET
SHIFT_CLK
A
QA
QB
QC
QD
Keyboard
R1
R2
R3
C1
C2
C3
LCD
DB[0:7]
RESET
\CS
\WR
\RD
LED
GPIO_1 / D+
ACC_ID
Handset_audio
MIC_GROUND
GPIO3&PTT
GPIO_2 / D-
USB_Vbus
INT_MIC
GPIO_4 / Hook
GPIO_0 / PwrOn
MMP
U7
U302
3*4 KEY Keyboard
Interface
EMIFS
FLASH.CS2#
RST_OUT
CS
CLOCK
DATA
U231
5VD
SPK+
SPK-
GPIO
GPIO
GPIO
McBSP
FILTER USB.DP
USB.DM
FLASH.D
p1
P5
C2
P4
Switch
P3
Menu
C1
Back P2
Down
C0
R2
R1R0
Keys Matrix
FLASH.A1
FLASH.WE#
FLASH.OE#
RS
A
B
S
UART2
GPIO
EMER
P6
C3
C4
UP
Power Supply
The power supply of the main board powers the front panel via U902 (5 V), and serves as the power
supply for LED indicator, backlight and USB devices. Then the power is further fed to U5, so as to power
the LCD module and U1 (serial-to-parallel converter IC).
Keys
The front panel includes 12 keys, each of which has different functions in different operation mode. The
identifications of each key on the front panel are realized by the 3*4 matrix keyboard.
Key Conventional Mode Trunking Mode
Programmable Keys S2, S3, S7, S8, S9, S10, and S12 S3, S7, S9, S10, and S12

UHF1 (400
–
470 MHz)
Circuit Description
13
Key Conventional Mode Trunking Mode
Navigation Key S5 and S11
OK/Menu Key S4
Back/Group Call Management
Key
S6
Power On/Off Key S1
Dial-
back/End/Home Screen
Key / S2
Redial/Answer/Call Key / S8
LCD
The front panel adopts TFT LCD to transfer data to U302 via the EMIFS data bus. The control signals
include read/write enable signal, memory chip select signal, LCD chip select signal and reset signal,
each of which is pulled up by R36, R35, R34, R33 and R6 respectively. The LCD module is powered by
U5 which converts 5 V into 3.3 V.
LED Indicator and Backlight
The LED enable signal is fed to the serial-to-parallel converter IC (U1), and then is output by U302. RX
status is indicated by green LED, and TX status by red LED. Backlight is activated upon any key press.
The red and green LEDs in series are powered by U902 (5 V) and controlled by Q2 and Q3. The
backlight is also powered by U902 (5 V) and controlled by Q1. Control signals are output via U1.
MMC
For details, please refer to Interface Definition.
Audio Output
The front panel provides two audio outputs: Handset_audio and Internal_audio (SPK±). Handset_audio
is the external output of received audio via MMC interface, while Internal_audio (SPK±) is connected to
the internal speaker.
Volume Control
The volume control is facilitated by the rotary encoder switch (U7), which generates signals to be fed to
U302 through GPIO17 and GPIO18 for volume adjustment.