HYT TC-500 User manual

8130050000400
TC-500

Contents
1. Introduction ........................................................................................................................................1
2. Product Controls ................................................................................................................................2
3. Software Specifications .....................................................................................................................5
4. Circuit Description .............................................................................................................................9
5. CPU Pins ...........................................................................................................................................16
6. Parts List 1 ........................................................................................................................................19
7. Tuning Description...........................................................................................................................28
8. Troubleshooting Flow Chart............................................................................................................38
9. Disassembly and Assembly ............................................................................................................41
10. Exploded View ................................................................................................................................45
11. Parts List 2 ......................................................................................................................................46
12. Packing Guide ................................................................................................................................49
13. PCB View.........................................................................................................................................50
14. Level Diagram.................................................................................................................................52
15. Block Diagram ................................................................................................................................53
16. Schematic Diagram ........................................................................................................................54
17. Specifications .................................................................................................................................57

Copyright Information
HYT is the trademark or registered trademark of Hytera Communications Co., Ltd. (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 describes 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.
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.
If you have any suggestions or would like to learn more details, please visit our website at:
http://www.hytera.com.

Service Manual Introduction
1
1. Introduction
Intended User
This manual is intended for use by qualified technicians only.

Product Controls Service Manual
2
2. Product Controls
1
2 3 4
5
67
89
10
11
12
13
(1) Antenna (2) LED Indicator
(3) Channel
Selector Knob
(4) Power
On-Off/Volume Control
Knob
(5) PTT Key (6) MONI Key (7) Microphone (8) Speaker
(9) Accessory Jack (10) Battery (11) Belt Clip (12) Battery Latch
(13) Charging Piece / / /
＊ PTT (Push-to-Talk) Key
Hold the PTT key to transmit, and release it to receive.
＊ SK1 Key
Side Key 1 is a programmable key that can be assigned with long press function and short press
function by your dealer.
Functions below are programmed by factory default:

Service Manual Product Controls
3
Key Operation Description
SK1 Key
Short press Squelch Off
Long press VOX
＊ Channel Selector Knob
Rotate the knob to select your desired channel.
＊ Power On-Off/Volume Control Knob
Rotate the knob to turn the radio on/off or to adjust the volume.
＊ LED Indicator
See the table below for LED and alert tone indications:
Item Indication
Wired-
Clone
To enter Wired Clone Mode:
Source radio: turn it on with MONI key
held for approximately 2 seconds;
Target radio: turn it on directly.
The LED on the source radio flashes red once during
the power-on process.
Status of the source radio in Wired
Clone Mode
(After the target radio is turned on and
the cloning cable is connected, press
the PTT key of the source radio to
begin cloning.)
The LED glows red during cloning process.
Error occurs during cloning:
 Clone Mode: At the start of cloning, frequency
band and Model ID will be checked. The LED
glows orange for 2 seconds and then goes out to
indicate a failed check. If the check is
successfully carried out but error occurs during
cloning, the LED will flash orange. In this
situation, press any key to make it go out.
 Factory Clone Mode: The LED flashes orange in
presence of error. Press any key to make it go
out.
The LED glows green once cloning is completed.
Status of the target radio in Wired
Clone Mode
 The LED glows green during cloning.
 The green LED goes out after cloning is
completed.

Product Controls Service Manual
4
Item Indication
Power On (to enter User Mode)
When the radio is turned on, a power-on alert tone
sounds.
When the radio is currently on a blank channel, it
sounds beep tones continuously.
Low Battery Alert
The LED flashes red, and the low-pitched tone
sounds every 20 seconds (programmable by the
dealer).
Transmitting
The LED glows red during transmitting.
When TOT timer expires, the radio sounds beep
tone continuously.
A TOT pre-alert tone sounds before the TOT timer
expires.
Receiving The LED glows green during receiving.
Scanning
The LED flashes green once per second during
scanning.
 Scan Start Alert (programmable by the dealer):
one beep will sound.
 Scan End Alert (programmable by the dealer):
two continuous beeps will sound.
Writing/Reading
 The LED glows red when the PC is reading data
from the radio.
 The LED glows green when the PC is writing
data into the radio.
Power Adjustment
 A low-pitched tone sounds when the radio
switches from high power to low power.
 A high-pitched tone sounds when the radio
switches from low power to high power.
VOX/Channel Lock
 One audio alert for enabling;
 Two audio alerts for disabling;

Service Manual Software Specifications
5
3. Software Specifications
3.1 Function List
 Channel Capacity: 1 – 16
 Channel Spacing: 25KHz/12.5KHz*
 Channel Scan
 RX/TX status indication (red/green LED)
 CTCSS/CDCSS (38 groups of CTCSS, 83 groups of CDCSS, and CTCSS Tail Invert by 180
degrees.)
 Low battery alert
 Battery Save
 Unlock Detection and Emergency Alarm
 2 Selectable Squelch Levels
 Monitor Button
 Time-out Timer (TOT)
 Squelch Tail Elimination
 PC Programming (manual/ automatic tuning)
 High/Low Power Switch (4.0/ 2.0W）
 Wide & Narrow Bandwidth Compatible*
 Wired Clone
 Battery Strength Indicator
 Manual Tuning
Note:
Note: *: indicates optional functions.
3.2 Programmable Key Functions
You dealer can assign any of the following functions to MONI key:
 None
 Monitor Button
 Monitor Momentary

Software Specifications Service Manual
6
 Scanning
 Squelch Off
 Squelch Off Momentary
 Power Adjustment
 Battery Strength Indicator
3.3 Description of Modes
3.3.1 User Mode
It is a conventional communication mode. The radio will enter this mode by default after power-on.
3.3.2 PC Programming Mode
The radio in User Mode enters PC Programming Mode through specific protocol based communication
with the programming software. In this mode, radio functions and adjustment parameters can be set
through the programming software (including User Version and Factory Version).
3.3.3 Wired Clone Mode
Description
Wired Clone Mode is an independent mode. To access other modes, you must restart the radio.
Wired Clone Mode includes Clone Mode and Factory Clone Mode.
 Clone Mode
Connect two radios using a cloning cable. Power on the source radio while holding MONI key; the
radio will enter Clone Mode in approximately 2 seconds. Then directly power on the target radio to
enter the User Mode. In this mode, data stored in EEPROM of the source radio will be cloned to
EEPROM of the target radio. The data transferred only involves channel data and common
parameters, excluding tuning data, version and serial No. of the model.
 Factory Clone Mode
Connect two radios using a clone cable. Power on the source radio while holding MONI key, the radio
will enter Clone Mode in approximately 2 seconds. Press MONI key afterwards to switch to Factory
Clone Mode. The target radio can be directly turned on to enter user mode. The data transferred
covers all data in EEPROM (including settings for the Manual Tune Switch), other than the serial No.
Process
 The LED flashes red once after the source radio enters the Wired Clone Mode. Press PTT to begin to
clone data to the target radio.

Service Manual Software Specifications
7
 During cloning, LED of the source radio solidly glows red, and LED of the target radio solidly glows
green. When cloning is completed, LED of the source radio solidly glows green, and the green LED
of the target radio goes out, which indicates the preparation for another clone.
 If any abnormal situation occurs during cloning, the source radio will stop cloning and its LED will
flash orange, which indicates the preparation for another clone.
 When cloning is completed, the source radio goes back to standby status. Press PTT again to begin
another clone.
3.3.4 Manual Tune Mode
In this mode, you can manually tune the frequency deviation, power level and squelch level and etc.
Description of Tuning:
To enter Manual Tune Mode
Hold the PTT and MONI key for 2 seconds while powering on the radio. The LED glows orange to
indicate that the radio has entered the Manual Tune Mode. When the keys are released, the radio will
enter item N of Tx group (N depends on the position where the Channel Selector Knob locates).
(Note: To enter the Manual Tune Mode, make sure its switch is set to Open via the programming
software. If this option is unchecked, the radio can not enter this mode, which helps avoid change of
parameters and degradation of radio performance caused by user’s misoperations.) Keep this option
unchecked after values are well adjusted from factory, to avoid any unexpected change of values. Such
values can only be reset and changed in Manual Tune Mode only. ）
To switch between TX Tuning items and RX Tuning items
Rotate the Channel Selector knob to switch between TX tuning items and RX tuning items.
The LED glows red for TX tuning items and green for RX tuning items.
To switch between tuning items within TX group/RX group
 TX group
CH1-CH9 respectively represent TX Low Power, TX High Power, CDCSS Balance, CDCSS
Deviation, CTCSS Deviation (low), CTCSS Deviation (medium), CTCSS Deviation (high), TX Low
Voltage Threshold and Max. TX Audio Deviation.
 RX group
CH10-CH13 respectively stands for SQL Normal Open, SQL Normal Close, Rx Low Voltage
Threshold and Bandpass Filter.
The LED solidly glows green during RX group tuning (CH10-CH13).
CH14-CH16 are unavailable and LED will go out.

Software Specifications Service Manual
8
To switch between wide and narrow bands
Under a certain tuning item, long press the PTT key (the LED flashes orange to indicate valid press) to
switch between wide and narrow bands. After the band is selected, the first frequency of the current
band is the frequency for tuning by default.
To switch the frequency
Under a certain band, short press the PTT key (the LED flashes green to indicate valid press) to switch
the frequency orderly.
To tune the value
Under a certain band, short press MONI key to increase the value in step of 1, or hold this key to
increase the value continuously in steps of 1. When it reaches the maximum value, pressing MONI key
again would increase the value from 0.
Special tuning items
 TX group
CH8 represents TX Low Voltage Threshold, which is related to AD sampling. Press the MONI key
after entering the above item, to activate AD sampling (including calculation) once. Rotate the
Channel Selector knob to save the current AD sampling value.
 RX group
CH10-CH12 represents SQL Normal Open, SQL Normal Close and RX Low Voltage Threshold
respectively. These items are related to AD sampling. Press the MONI key after entering the above
item, to activate AD sampling (including calculation) once. Rotate the Channel Selector knob to
save the current AD sampling value.
About the Key-press
 Short press: key-press time shorter than 1 second;
 Long press: key-press time longer than 1 second.

Service Manual Circuit Description
9
4. Circuit Description
4.1 General Principle Diagram
The general circuit is composed of RDA chip circuit, TX circuit, RX circuit, power supply circuit, control
circuit, etc. See the block diagram below:
PWER
VOX_DET
MIC IN
TX_EN
AF
RFOUT
Synthesizer
Figure 1
 RDA Chip Circuit
This chip is highly integrated. Its function includes voice signal processing/modulation/demodulation,
DSP, VCO, PLL, LNA and RF IF. The voice signal from MIC goes to RDA chip for amplification. Next,
the amplified voice signal will undergo a series of processing including A/D conversion, filtering,
pre-emphasizing, gain control, amplitude limit and D/A conversion. Then the analog voice signal is
delivered to VCO and amplified to a signal with 8dBm. When the RX RF signal enters this chip, it
would experience demodulation, filtering, de-emphasizing and gain control. Finally, the signal is
output to the audio amplifier.
 TX Circuit

Circuit Description Service Manual
10
The modulated RF signal from RDA chip goes to Q407 and Q402 for amplification, and then further
amplified by Q403. Then the amplified signal is delivered to low-pass filter to filter out the high-order
harmonics. Finally, it is sent via the antenna.
 RX Circuit
After going through LPF and amplitude limiter, the RF signal received from the antenna enters Q501
LNA for amplification. Then the BPF will filter the signal to remove other unwanted signals. The
resulting signal is delivered to RDA chip for demodulation. After that, the voice signal from
demodulation is output U302 for amplification, which is finally output from the speaker.
 Power Circuit
LDO U619 converts the 6V power supply into two 5V, which LDO U621 will convert into two 3.3v
power supplies, powering VCC and VDD respectively. VCC powers CPU, while VDD powers RDA
chip. Then Q409 converts the 5V power supply to VT to power the TX circuit.
4.2 Realization Methods of Basic Functional Modules
4.2.1 RDA Chip Circuit
This chip is highly integrated. Its function includes voice signal processing/modulation/demodulation,
DSP, VCO, PLL, LNA and RF IF.
RDA Chip Circuit
Figure 2
The reference clock signal of RDA chip is provided by 26MHZ crystal oscillator. The block diagram is

Service Manual Circuit Description
11
given below:
LDO
Syntheizer
LNA
Switch
RF_IN
-
-
0/90
+
+
I ADC
Q ADC
DSP Core
Audio filter
Sub CH filter
FM Modem
AFC loop
DAC
ADC
I PGA
Q PGA
PA
MCU
GPIO
GPIO0~7
Interfac
e
BUS
……PDN
SPI
I2C
RSSI
VCO
PA_driver
XTAL
MIC
DVDD
AVDD
3.3~
4.8V
After entering RDA chip via MIC, the voice signal will undergo A/D conversion to get digital signal, which
will be delivered to DSP for further processing such as filtering, amplification, amplitude-limiting and
pre-emphasizing. Then the resulting voice signal is modulated to the internal VCO and output after being
amplified by the driver amplifier. At the RX end, the received RF signal will go to LNA for amplification
first, and then go to IF demodulation circuit to get demodulated voice signal. After gain control, such
signal is converted into digital signal, which will enter DSP for further processing such as filtering,
amplification and de-emphasizing.
The function of RDA is subject to MCU U622 and its reference clock signal is from 26MHZ crystal
oscillator. This chip is applicable to UHF (400~520MHZ) and VHF (134~174MHZ). The NF can be up to
3dB and IIP3 up to -6dBm, meeting GB and FCC requirements. Its RF output may reach up to 8dBm.
4.2.2 RF Power Amplifier Circuit (TX Section)
The block diagram of the RF power amplifier circuit is shown in the figure below:

Circuit Description Service Manual
12
BIAS DOWN
APC
U401
APC
BAT
Figure 3
The modulated RF signal from RDA chip goes to Q407 and Q402 for amplification, and then further
amplified by Q403. Then the amplified signal is delivered to low-pass filter to filter out the high-order
harmonics. Finally, it is sent via the antenna. The control signal “VT” is used to control the operation of
driver amplifier (Q407 and Q402). U401 works for auto power control (APC).
4.2.3 Receiver Circuit (RX Section)
The Block Diagram of RX Circuit is shown as below:

Service Manual Circuit Description
13
LNA
Q501
AT41511
ANT LPF
RX_EN
BPF1
VT
D401 D402
Figure 4
The RF signal is received via the antenna. After going through LPF and amplitude limiter, the signal is
amplified by Q501 LNA. The LNA adopts 2SC3356 with current <5mA and its gain is about 12dB.
Next, the BPF will remove the interference signal in amplified RF signal. Then the resulting signal goes
to RDA chip for further processing. The processed signal is delivered to U302 for amplification and finally
output by the speaker.
4.2.4 MCU Control, Signal Processing and Audio Amplification
Circuit diagram of this section is shown as below:

Circuit Description Service Manual
14
U622
MCU
MC9S08AC60
SDA/SCL
RESET
EN0/EN1/EN2/EN3
AF
VOX_DET
1
2
PTT/SK1/SK2
RXD
TXD
1
2
CSS/CODE/INT/SDO
/RXON/TXON/SQ/PDN
SDIO/SCLK/SEBN/PD
N
EXT_PTT
/EXT_MIC
BAT
Figure5
MCU Control Circuit
MCU control circuit is composed of MCU, EEPROM, keys, etc. This section has the following functions:
to initialize data of the radio and save data to EEPROM; to detect battery voltage and signals from
external keys, LD and VOX, and to make response; to transmit required data to PLL based on the
channel encoding status; to switch and control RX/TX based on the input PTT signal; to switch the
squelch circuit on/off based on the input signaling decode signal and squelch level signal; to control
circuits of high/low power switch, audio power amplifier, RDA chip power supply, RX power supply and

Service Manual Circuit Description
15
TX power supply; (for programming) to communicate with PC via RXD/TXD based on the RS232
protocol, and transmit/receive data to/from PC.
RDA Chip Control
By controlling the RDA chip, the MCU can realize these services: frequency setting, frequency
bandwidth, reference clock, sleep mode, SQ, VOX, squelch, frequency deviation, voice filtering,
signaling encoding/decoding, pre-emphasizing, gain control, amplitude limiting, de-emphasizing, etc.
Audio Amplifier
The audio signal output from U622 is amplified by the audio power amplifier (U302) to drive the speaker
directly.
4.2.5 Power Supply Section
Block diagram of power supply circuit is shown as below:
Figure 6
LDO U619 converts the 6V power supply into two 5V, which LDO U621 will convert into two 3.3v power
supplies, powering VCC and VDD respectively. VCC powers CPU, while VDD powers RDA chip. Then
Q409 converts the 5V power supply to VT to power the TX circuit.

CPU Pins Service Manual
16
5. CPU Pins
PIN No. Pin Name Definition I/O Description
1 PTC4 Reserved I Reserved
2 IRQ/TPMCLK Reserved I Reserved
3 RESET RESET I Reset
4 PTF0/TPM1CH2 BEEP O Tone
5 PTF1/TPM1CH3 VRCR O PWM output for freq. adjustment
6 PTF2/TPM1CH4 APC O PWM output for PA APC
7 PTF3/TPM1CH5 CSS I
Detection pin, CDCSS status
output
8 PTF4/TPM2CH0 TXON I TX status detection pin
9 PTC6 PWER O Radio power control pin
10 PTF7 Reserved I Reserved
11 PTF5/TPM2CH1 RXON I RX status detection pin
12 PTF6 Reserved I Reserved
13 PTE0/TxD1 UART_TXD O Port
14 PTE1/RxD1 UART_RXD I Port
15 PTE2/TPM1CH0 INT I Detection pin, programmable
16 PTE3/TPM1CH1 CODE I/O
Detection pin, modulated digital
signal input/output
17 PTE4/SS1 SEBN O SPI port of communication
18 PTE5/MISO1 SDO I SPI port of communication
19 PTE6/MOSI1 SDIO O SPI port of communication
20 PTE7/SPSCK1 SCLK O SPI port of communication
21 VSS VSS / Ground
22 VDD VDD / Power Supply

Service Manual CPU Pins
17
PIN No. Pin Name Definition I/O Description
23 PTG0/KBI1P0 SQ I Detection pin, SQ status check
24 PTG1/KBI1P1 TX_EN O TX power supply control
25 PTG2/KBI1P2 RX_EN O RX power supply control
26 PTA0 EN1 I Rotary switch
27 PTA1 EN2 I Rotary switch
28 PTA2 EN3 I Rotary switch
29 PTA3 EN4 I Rotary switch
30 PTA4 Reserved O Reserved
31 PTA5 Reserved O Reserved
32 PTA6 Reserved O Reserved
33 PTA7 PDN O Sleep control
34 PTB0/TPM3CH0/AD1P0 Reserved O Reserved
35 PTB1/TPM3CH1/AD1P1 Reserved O Reserved
36 PTB2/AD1P2 Reserved O Reserved
37 PTB3/AD1P3 VOX_DET AD VOX control
38 PTB4/AD1P4 EXT_MIC I External microphone
39 PTB5/AD1P5 EXT_PTT I External PTT
40 PTB6/AD1P6 APA_EN O Audio power amplifier switch
41 PTB7/AD1P7 R_LED O Red LED indicator
42 PTD0/AD1P8 G_LED O Green LED indicator
43 PTD1/AD1P9 Reserved O Reserved
44 VDDAD VDD_AD / Power supply for digital circuit
45 VSSAD VSS_AD / Ground (digital)
46 PTD2/KBI1P5/AD1P10 SDA I/O External EEPROM
47 PTD3/KBI1P6/AD1P11 SCL O External EEPROM