Hytera Communications Corporation Limited Hytera Communications Co., Ltd Global Customer Service Center TC508 Technical Training Edited by.

Hytera Communications Corporation Limitedwww.hytera.com

Hytera Communications Co., Ltd

Global Customer Service Center

TC508 Technical Training

Edited by Adam Sun01MAR2012


1. Function & Feature

2. Technical Specification

3. Software & Setting

4. Disassembly & Re-assembly

5. Circuit Description & Analysis

6. Trouble Shooting

Content



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



Radio Overview

①PTT

②SK1

③SK2

④Antenna

⑤Channel Selector Knob

⑥Radio On-Off/Volume

Control Knob

⑦Speaker

⑧Microphone



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. Trouble Shooting

Content



Testing Specifications

General

Freq. Range400-420MHz, 450-470MHz

136-154MHz, 146-174MHz

Channel Capacity 16

Channel Space 25KHz/ 12.5KHz*

Working Voltage 7.4V DC

Battery Capacity 1300mAh (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

antenna250g

Frequency Stability ±2.5ppm

RX

Sensitivity ≤0.224μV

Adjacent Channel

Selectivity65dB

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 Output 4W/ 2W

Spurious and

Harmonics≤-26dBm

Modulation Limiting ≤5KHz

FM Noise ≥40dB

Audio Distortion ≤5%



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



Status Indication



Status Indication







6. Trouble Shooting

Content



Programming Software

Now, please open the programming software.


Software Adjustment

Please do not tune these items if not repairing/testing necessary.

We can enter Tuning Mode by Programming Software.








6. Trouble Shooting

Content



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

2 3

5

4



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.







6. Trouble Shooting

Content



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



Block Diagram


U601MCU

SRT3210

MICJACK

VOX_DETQ611D616

R204C204C205

R607R632R206

AF AMPU302

SWVOLUME

S201

SW_C

HANN

AL

RESET ICU605

E2ROMU603

DATA/STB/CK

LD

TX_C

TL

SAVE

SDA/SCL

EC0/EC1/EC2/EC3

MODE

AF

VOX

1

2

PTT/SK1/SK2

APC

MIC

INR_LE

D

T_LE

D

LEDD601

LEDD602

SPK

MODE_OUTRXD

TXD

SP_JACKJ3

PJ-D3027D

1

2

MICB201

QT_OUT

T/R

QT_OUT

QT_MODULATING FILLER

AF_MODULATING FILLER

BATTERYG602

W/N

AF_SWQ302

BEEPBE

EP

AF_M

UTE

RF_M

UTE

5. Circuit Description & AnalysisMCU Control, Signal Processing and Audio Power Amplification



1) MCU Control CircuitMCU 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 controlcircuits 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 Circuita. TX Baseband ProcessingThe 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.



b. RX Baseband ProcessThe 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 AmplifierThe audio signal output from U601 is amplified by the audio power amplifier (U302) to drive the speaker directly.


5. Circuit Description & AnalysisMCU&Power



MCU&Power



AF AMP and Speaker/MIC interface


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.


Power supply

LDOU604

LDOU602

LDOU606

V_BAT

TX

_CT

L

SAV

E

VT

VR SW Q604Q305

V_SAVE

VR

VCC

VDD

5V

RF_

MU

TE


Power supply



PLL&VCO


PLL Frequency SynthesizerThe 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.

U601MCU

SRT3210

TX/RX VCO Q102

QT_MODE FILLER

R103C132

PLL LOOP FILTER

1

3

2

4

DATA/STB/CK

LD

QT_OUT

CP

BUFFER AMPQ105

2SC4226

LOCAL OSCILLATOR AMPQ104

2SC5108

VDD

MODE

T/R SWQ103D105

Crystal XT 101

38.4MHz

T/R

PLLU102

MB15E03SL


PLL&VCO


1) PLLThe 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) VCOThe 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.



PLL&RX



PLL and 38.4MHz Ref. Crystal



TX&VCO


VCO



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



TX


TX/RX VCO Q102

POWERMATCH ANT LPF

APCU401

VT

LO

VT

POWER AMP Q403 RD07

POWER AMPQ402RD01

POWER AMPQ401

2SC4226


2SC5108

SWQ405

DTC114EE

T/R SWQ103D105

VR SWD405

VT SWD404

APC_SWQ404

DTC114YE

APC

T/R


2SC4226


RF power amplifier


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.


TX/RX switch and RF LPF



RF AMP and TX final AMP



Current detect and APC



RX


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.


RX




RX LNA and BPF



Mixer and IF filtering and amplifier



IF processing IC, noise selecting freq. and AF HPF


Level Diagram








6. Trouble Shooting

Content


PCB Top Side

AF AMPTDA2822

MIC

Memory24C1632.768KHZ

Crystal

CPU

APC Circuit

Antenna Soldering

Point

6. Trouble Shooting


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


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


6. Trouble Shooting

1. Can not power on

2. Voice abnormal

3. TX problem

4. RX problem

5. Unlock


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


1. Can’t Power On

6. Trouble Shooting

U604

U606


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.


6. Trouble Shooting

U606

RD07

APCC420

3. TX Problem (No TX power or low power)

DescriptionAfter power on, press PTT, LED is red, but no TX power output or it is low.AnalysisCheck 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.


6. Trouble Shooting

4. RX Problem (Low RX or No RX)

DescriptionAfter power on, TX is normal, but, no RX(green led is not on) or RX sensitivity is low.AnalysisCheck 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 2nd 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


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


THANKSPlease call or email Hytera Global Customer Service Center, if you have any

question about Hytera Product.

Service Direct Line: +86-755-86137081

Email: [email protected]

Website: www.hytera.com

mailto:[email protected]

http://www.hytera.co/

Hytera Communications Corporation Limited Hytera Communications Co., Ltd Global Customer Service Center TC508 Technical Training Edited by.

Documents

content slide

tight slide

01mar2012 slide

channel scan battery

rx tc101

tx tc101

rx cv voltage

hours of battery life