1. Hytera Communications Corporation Limitedwww.hytera.com Hytera Communications Co., Ltd Global Customer Service Center TC508 Technical Training Edited by Adam Sun 01MAR2012

2. Hytera Communications Corporation Limitedwww.hytera.com 1. Function & Feature 2. Technical Specification 3. Software & Setting 4. Disassembly & Re-assembly 5. Circuit Description & Analysis 6. Trouble Shooting Content

3. Hytera Communications Corporation Limitedwww.hytera.com 1. Function & Feature The TC-508, one of the market-leading products in Hytera's commercial radio series, is an ideal choice for facilities, hospitality, manufacturing, retail, education and construction. As the affordable and reliable two-way radio for business and industry, TC-508 can largely enhance your productivity and management efficiency. The excellent design of HYT’s compact TC-508 portables guarantees superior ergonomics. Moreover, it can ensure a great performance in any operating conditions, thanks to MIL-STD 810 & Hytera's 5-year ALT test. Besides, TC-508 provides up to 14 hours of battery life to ensure long-lasting performance and convenience. Affordable price and distinct performance - TC-508 deserves your trust. Features

4. Hytera Communications Corporation Limitedwww.hytera.com 1. Function & Feature Radio Overview ① PTT ② SK1 ③ SK2 ④ Antenna ⑤ Channel Selector Knob ⑥ Radio On-Off/Volume Control Knob ⑦ Speaker ⑧ Microphone

5. Hytera Communications Corporation Limitedwww.hytera.com 1. Function & Feature Main Functions High/Low Power Switch Monitor CTCSS/CDCSS and Tail eliminate Channel Scan Battery Save Low Battery Alert / Battery Strength Indicator Voice Operated Transmit (VOX) Busy Channel Lockout (BCL) Time-out-Timer (TOT) PC Programmable Wired Clone Selectable Carrier Squelch Level (2 levels: normal or tight)

6. Hytera Communications Corporation Limitedwww.hytera.com 1. Function & Feature 2. Technical Specification 3. Software & Setting 4. Disassembly & Re-assembly 5. Circuit Description & Analysis 6. Trouble Shooting Content

7. Hytera Communications Corporation Limitedwww.hytera.com 2. Technical Specification Testing Specifications General Freq. Range 400-420MHz, 450-470MHz 136-154MHz, 146-174MHz Channel Capacity16 Channel Space25KHz/ 12.5KHz* Working Voltage7.4V DC Battery Capacity1300mAh (Li-ion) Working Time (5-5-90)> 11 hours Working Temperature-25 ℃ ~+60 ℃ Dimensions （ H×W×D ） (with battery, without antenna) 113mmx 54mmx35mm Weight (with battery and antenna 250g Frequency Stability ±2.5ppm RX Sensitivity≤0.224μV Adjacent Channel Selectivity 65dB Intermodulation 60dB Spurious Response Rejection 65dB Rated Audio Power 0.5W (SPK impedance is 16 ohm) Rated Audio Distortion ≤5% （ 0.5W ） TX RF Power Output4W/ 2W Spurious and Harmonics ≤-26dBm Modulation Limiting≤5KHz FM Noise≥40dB Audio Distortion≤5%

8. Hytera Communications Corporation Limitedwww.hytera.com 2. Technical Specification CV Testing and Adjust CV voltage High Freq.Low Freq. RX TC101 3 ～ 4V ≥0.5V TX TC101 3 ～ 4V ≥0.5V CV Testing Point TC101 RX and TX use the same VCO. When adjusting TC101, we need check TX and RX CV voltage at same time. Notice

9. Hytera Communications Corporation Limitedwww.hytera.com 2. Technical Specification Status Indication

10. Hytera Communications Corporation Limitedwww.hytera.com 2. Technical Specification Status Indication

11. Hytera Communications Corporation Limitedwww.hytera.com 1. Function & Feature 2. Technical Specification 3. Software & Setting 4. Disassembly & Re-assembly 5. Circuit Description & Analysis 6. Trouble Shooting Content

12. Hytera Communications Corporation Limitedwww.hytera.com 3. Software & Setting Programming Software Now, please open the programming software.

13. Hytera Communications Corporation Limitedwww.hytera.com Software Adjustment Please do not tune these items if not repairing/testing necessary. We can enter Tuning Mode by Programming Software. 3. Software & Setting

14. Hytera Communications Corporation Limitedwww.hytera.com 1. Function & Feature 2. Technical Specification 3. Software & Setting 4. Disassembly & Re-assembly 5. Circuit Description & Analysis 6. Trouble Shooting Content

15. Hytera Communications Corporation Limitedwww.hytera.com 4. Disassembly & Re-assembly Disassembly steps as following: 1.Turn the radio off 2.Remove antenna, channel selector knob, channel switch knob. (1,2,3) 3.Remove the fixed screws. (4,5) 4.Lift the chassis by its bottom and pull it out of the radio case. 1 23 5 4

16. Hytera Communications Corporation Limitedwww.hytera.com 4. Disassembly & Re-assembly 5.Remove the fixed screws on the PCB and side PTT board 6.Remove the antenna terminal with soldering 7.Lift the PCB and remove it from the chassis. The Re-assembly method is similar and reverse the steps.

17. Hytera Communications Corporation Limitedwww.hytera.com 1. Function & Feature 2. Technical Specification 3. Software & Setting 4. Disassembly & Re-assembly 5. Circuit Description & Analysis 6. Trouble Shooting Content

18. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis The Circuit including: The general circuit is composed of TX circuit, RX circuit, power supply circuit, control circuit and etc. 1.RF parts : RX, TX 2.FGU : PLL and VCO 3.Control Circuit : power supply and CPU 4.Baseband

19. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis Block Diagram

20. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis MCU Control, Signal Processing and Audio Power Amplification

21. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis MCU Control, Signal Processing and Audio Power Amplification 1) MCU Control Circuit MCU control circuit is composed of MCU, EEPROM, and 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, VCO power supply, RX power supply and TX power supply; (for programming) to communicate with PC via RXD/TXD based on the RS232 protocol, and transmit/receive data to/from PC. 2) Signal Processing Circuit a. TX Baseband Processing The audio signals input from MIC are divided into two parts. One part enters U601, and is then converted into digital signal by analog-to-digital conversion (ADC). Afterwards, the converted signal will go through a series of processing including low- pass filtering, AGC, companding, high-pass filtering, encrypting and pre-emphasizing, and then it will be output as baseband signal after digital-to-analog conversion (DAC). The baseband signal is processed by the active low-pass filter and then sent to VCO for modulation; for the other part, it will go through VOX circuit (Q611 and D616) and then sent to MCU for VOX processing.

22. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis MCU Control, Signal Processing and Audio Power Amplification b. RX Baseband Process The demodulated IF signals with CTCSS/CDCSS signaling enter U601 for decoding. After analog-to-digital conversion, the IF signals will be converted into digital signals, which go to low-pass filter for filtering and then are divided into two parts. One part is processed by CTCSS/CDCSS decoder, and the other is processed by high-pass filter and then is subject to de-emphasis, decryption, signal expansion etc, and finally digital-to-analog conversion to output audio signal. 3) Audio Power Amplifier The audio signal output from U601 is amplified by the audio power amplifier (U302) to drive the speaker directly.

23. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis MCU&Power

24. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis MCU&Power

25. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis AF AMP and Speaker/MIC interface

26. Hytera Communications Corporation Limitedwww.hytera.com The 7.4V battery voltage is converted to 5V via DC-DC module U604, and further converted via LDO U602 to 3V including two channels: VCC and VDD. VCC powers CPU and VDD powers PLL circuit. The 5V voltage will be converted via LDO U606 to 4.5V including two channels: VT and V- SAVE. V-SAVE powers VCO circuit and VT powers TX circuit. Finally, V- SAVE controlled by Q604 and Q305 outputs VR, which supplies RX circuit. 5. Circuit Description & Analysis Power supply

27. Hytera Communications Corporation Limitedwww.hytera.com Power supply 5. Circuit Description & Analysis

28. Hytera Communications Corporation Limitedwww.hytera.com PLL&VCO 5. Circuit Description & Analysis PLL Frequency Synthesizer The PLL circuit mainly provides the first local oscillator signal (for RX) and RF carrier signal (for TX). It is composed of VCO and PLL chip, allowing frequency tracking and channel switching under the control of MCU signals.

29. Hytera Communications Corporation Limitedwww.hytera.com PLL&VCO 5. Circuit Description & Analysis 1) PLL The step frequency of PLL circuit is 5 KHz or 6.25 KHz. In U101, the 38.4MHz reference oscillator signal is divided into 5 KHz or 6.25 KHz reference frequency via a fixed counter in PLL. The signal from VCO enters the PLL after processed by the buffer amplifier, and then it is applied to the variable frequency divider in PLL for division. After division, the signal is compared with the reference frequency at the phase detector (PD) in PLL. The signal from the PD passes through a low-pass filter and then is applied to the varactors (D101 and D102) of VCO to control the output frequency. Then the RF signal is processed by the buffer amplifiers (Q104 and Q406), and controlled by D404 and D405 to only serve as TX signal or RX first local oscillator signal. 2) VCO The VCO section is realized by the three-point capacitor oscillator circuit. TX VCO and RX VCO share the same oscillator circuit. Q103 controls the switch between TX VCO and RX VCO. Note: If the PLL is unlocked, the LD pin of U101 outputs low level. If the microprocessor detects such situation, TX/RX operation is prohibited, and an alarm sounds.

30. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis PLL&RX

31. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis PLL and 38.4MHz Ref. Crystal

32. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis TX&VCO

33. Hytera Communications Corporation Limitedwww.hytera.com VCO 5. Circuit Description & Analysis

34. Hytera Communications Corporation Limitedwww.hytera.com The audio signal from MIC is sent to the MCU chip (U601) directly. The baseband signal processing circuit in U601 converts the amplified audio signal to digital signal via A/D conversion, and then converts the digital signal to analog audio signal via D/A conversion after all processing procedures such as filtering, signal compression, encryption, pre-emphasis, TX gain control and amplitude limiting are completed. Then the analog audio signal from MCU passes through the low-pass filter circuit and directly goes to VCO for frequency modulation. The modulated HF carrier signal passes through the buffer amplifiers (Q104 and Q406), and goes to the amplifier (Q401) through the RF switch (D404). Then the amplified RF signal enters the low-pass filter circuit after it is further amplified by the pre-driver (Q402) and final-stage power amplifier (Q403), and then it will be finally transmitted via antenna after ultra harmonics is removed. TX 5. Circuit Description & Analysis

35. Hytera Communications Corporation Limitedwww.hytera.com TX 5. Circuit Description & Analysis

36. Hytera Communications Corporation Limitedwww.hytera.com RF power amplifier 5. Circuit Description & Analysis The modulated carrier signal from VCO is pre-amplified at Q104 and Q406, and controlled at D404 and D405. Then it is amplified by the front-stage amplifier Q401, the pre-driver Q402 and the final-stage amplifier Q403 orderly. Finally it goes to the LC low-pass filter (LPF) and is transmitted from the antenna after high-order harmonics are removed by LPF. APC circuit is composed of Q404, Q405 and U401. U401 controls the bias voltage at the gates of Q402 and Q403, to control TX current and to further regulate power.

37. Hytera Communications Corporation Limitedwww.hytera.com TX/RX switch and RF LPF 5. Circuit Description & Analysis

38. Hytera Communications Corporation Limitedwww.hytera.com RF AMP and TX final AMP 5. Circuit Description & Analysis

39. Hytera Communications Corporation Limitedwww.hytera.com Current detect and APC 5. Circuit Description & Analysis

40. Hytera Communications Corporation Limitedwww.hytera.com RX 5. Circuit Description & Analysis After the RF signals are received from the antenna, the undesired out-of-band signals are filtered out at the bandpass filter. Then the remaining RF signals are amplified by LNA Q501. Afterwards, the amplified signal goes through the bandpass filter again to eliminate undesired out-of-band interference signal. After being filtered and amplified, the RF signals and first LO signals are mixed at Q502, and then the mixed signal is filtered by crystal filter XF501 to get 38.85MHz differential signals as the first IF signal. After being amplified by Q506, the IF signal goes to chip U611, where the signal will be mixed with the second LO signal (38.4MHZ). Next, the signals will be filtered by CF501 to produce 450KHz IF signal. When the IF signals are processed by demodulation circuit (including U611 and CD501) to generate audio signals, which are delivered to IC Q613 for amplification and output in two channels. After simple filtering, one channel of signals is sent to MCU U601 for CTCSS/CDCSS decoding; for the other channel, it goes through two stages of low-pass filter first, and then it goes to high-pass filter U610 (consisting of four operational amplifiers) for audio processing. Finally, the signals will be sent to audio power amplifier U302 for amplification so as to drive the speaker.

41. Hytera Communications Corporation Limitedwww.hytera.com RX 5. Circuit Description & Analysis

42. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis RX LNA and BPF

43. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis Mixer and IF filtering and amplifier

44. Hytera Communications Corporation Limitedwww.hytera.com 5. Circuit Description & Analysis IF processing IC, noise selecting freq. and AF HPF

45. Hytera Communications Corporation Limitedwww.hytera.com Level Diagram 5. Circuit Description & Analysis

46. Hytera Communications Corporation Limitedwww.hytera.com 1. Function & Feature 2. Technical Specification 3. Software & Setting 4. Disassembly & Re-assembly 5. Circuit Description & Analysis 6. Trouble Shooting Content

47. Hytera Communications Corporation Limitedwww.hytera.com PCB Top Side AF AMP TDA2822 MIC Memory 24C16 32.768KHZ Crystal CPU APC Circuit Antenna Soldering Point 6. Trouble Shooting

48. Hytera Communications Corporation Limitedwww.hytera.com 6. Trouble Shooting Volume Switch SPK socket MIC socket Power management IC 38.85MHZ Crystal Filter 450 IF IC:4116 Audio process IC 2902 PLL IC MB15E03SL VCO 50C24 Power AMP RQ0002 PTT board Channel switch Battery connector PCB Bottom Side

49. Hytera Communications Corporation Limitedwww.hytera.com 6. Trouble Shooting ANT test point PTT test point CV test point LD checking point BPF test point External power supply connection point PCB Key Testing Point

50. Hytera Communications Corporation Limitedwww.hytera.com 6. Trouble Shooting 1.Can not power on 2.Voice abnormal 3.TX problem 4.RX problem 5.Unlock

51. Hytera Communications Corporation Limitedwww.hytera.com 1. Can’t Power On 6. Trouble Shooting Description: After connecting 7.4V DC voltage, the radio has not any response. Analysis: Check power supply circuit and control circuit. Checking Steps:  Battery connector is connected well with main radio  Power switch  The pin 1 of Regulator IC U604 output is 5V or not  U602 output is 3V or not  CPU power on crystal 32.768KHz  CPU pins is false soldering or broken

52. Hytera Communications Corporation Limitedwww.hytera.com 1. Can’t Power On 6. Trouble Shooting U604 U606

53. Hytera Communications Corporation Limitedwww.hytera.com 6. Trouble Shooting 2. Voice Abnormal (no voice when power on; abnormal voice) Description No voice or abnormal voice when power on the radio Analysis AF output circuit is composed of volume switch S201, AF amplifier U302 and power supply tube Q303, speaker socket and speaker. Checking Steps  Speaker, speaker line’s soldering  Speaker socket is connected well or not  Volume switch  AF amplifier IC U302 TDA2822 is working well or not. Q303 (717) is damaged or not.

54. Hytera Communications Corporation Limitedwww.hytera.com 6. Trouble Shooting U606 RD07 APC C420 3. TX Problem (No TX power or low power) Description After power on, press PTT, LED is red, but no TX power output or it is low. Analysis Check RF AMP and APC circuit. Test TX power supply, Q611/5T, U430/APC, and test TX power by communication analyzer to judge which stage has problem. Checking Steps  6pin of U606 output voltage is 4.5V or not  Check TX current, High power is about 1.6A, and 0.8A Low Power. If normal, that means APC circuit has no problem, generally, the power amplifier Q403 (RD07) is burnt.  Check the positive pole of C420 in APC circuit has about 3.5V voltage output, or not  Check the bias voltage of final power amplifier is normal or not  Check driver amplifier and final power amplifier RD07 is damaged or not  Test the input pin’s voltage of Q403 is 3-5V while pressing PTT. If not, check the APC circuit.

55. Hytera Communications Corporation Limitedwww.hytera.com 6. Trouble Shooting 4. RX Problem (Low RX or No RX) Description After power on, TX is normal, but, no RX(green led is not on) or RX sensitivity is low. Analysis Check RX filtering circuit or IF processing circuit. Checking Steps  VHF/UHF RX sensitivity is 0.25/0.28µV. We use signal injection to check which stage has problem. The important is IF AMP and LNA/Mixing circuit. The first IF is 38.85MHz, the 2 nd IF is 450kHz.  Check the carrier squelch level, and CTCSS setting.  The output voltage of Q604 is 5V or not  Mixer Q502 is damaged or not  450kHz filter is loose or damaged or not  38.85MHz filter is normal or not  IF processing IC U611 is false soldered or damaged  Demodulator is loose or damaged or not

56. Hytera Communications Corporation Limitedwww.hytera.com 6. Trouble Shooting Description After power on, the radio sounds “Dudu…”. And it can’t transmit or receive signal. Analysis: check RX/TX common circuit and PLL circuit. Checking Steps:  Power supply of PLL is 3V or not  CV voltage is normal or not  86pin of CPU is normal or not (H:Lock, L:Unlock)  38.4MHz crystal is normal or not  IC U101 PLL part is false soldering or damaged 5. Unlock

57. Hytera Communications Corporation Limitedwww.hytera.com THANKS Please call or email Hytera Global Customer Service Center, if you have any question about Hytera Product. Service Direct Line: +86-755-86137081 Email: overseas.service@hytera.comoverseas.service@hytera.com Website:www.hytera.comwww.hytera.com