Kirisun PT6800 User manual

PT6800 Service Manual
Dangerous!
Do not connect the AC power or DC power over 8.6V with
any connector or terminal of the radio. Otherwise it will cause
fire, electric shock or damage to the radio.
Warning!
Do not reverse power connection.
It may cause harm to the radio if signal input on the antenna
connector is larger than 20 dBm (100mW).
Do not turn on the radio before the antenna or load
connection is completed.
If the antenna has been damaged, do not use the radio.
Damaged antenna may cause light burning on skin.
Though the radio is waterproof, it's better to avoid putting it
in rain or snow, or any other liquid to ensure its life and
performance.
Statement!
Kirisun Electronics (Shenzhen) Co., Ltd owns the copyright
of KSP6800 software.
Unauthorized duplication of KSP6800 software is strictly
prohibited.
Kirisun Electronics (Shenzhen) Co., Ltd owns the copyright
of the MCU software.
Kirisun Electronics (Shenzhen) Co., Ltd owns the copyright
of the radio outward appearance/structure/circuit design.
Kirisun Electronics (Shenzhen) Co., Ltd owns the copyright
of this service manual. Unauthorized publication is prohibited.
Kirisun Electronics (Shenzhen) Co., Ltd owns the
trademarks “KIRISUN”, “”, and “科立讯”.
Contents
Chapter 1 Overview.......................................................................................... 1
Chapter 2 External View and Functional Keys ................................................ 1
Chapter 3 Mode Introduction ........................................................................... 2
Chapter 4 Circuit Description........................................................................... 3
Chapter 5 Function Description and Parameter Setting ................................... 8
Chapter 6 Disassembly for Repair.................................................................. 10
Chapter 7 Adjustment ..................................................................................... 12
Chapter 8 Specifications ................................................................................. 16
Chapter 9 Servicing and Testing Equipment .................................................. 16
Chapter 10 Troubleshooting ........................................................................... 16
Appendix 1 Abbreviations .............................................................................. 17
Appendix 2 Electronic Parts List.................................................................... 17
Appendix 3 Structural Parts List .................................................................... 23
Appendix 4 Accessories.................................................................................. 24
Figure 1 PT6800 Block Diagram ................................................................... 25
Figure 2 PT6800 Main Board Schematic Circuit Diagram............................ 26
Figure 3 PT6800 Main Board Top Layer Position Mark Diagram ................ 27
Figure 4 PT6800 Main Board Bottom Layer Position Mark Diagram .......... 28
Figure 5 PT6800 Main Board Top Layer Position Value Diagram................ 29
Figure 6 PT6800 Main Board Bottom Layer Position Value Diagram.......... 30
Figure 7 PT6800 Key Board Schematic Circuit Diagram.............................. 31
Figure 8 PT6800 Key Board Top Layer Position Mark Diagram .................. 32
Figure 9 PT6800 Key Board Bottom Layer Position Mark Diagram ............ 33
Figure 10 PT6800 Key Board Top Layer Position Value Diagram................ 34
Figure 11 PT6800 Key Board Bottom Layer Position Value Diagram.......... 35
Figure 12 PT6800 PTT Board Schematic Circuit Diagram ........................... 36
Figure 13 PT6800 PTT Board Top Layer Position Mark Diagram................ 37
Figure 14 PT6800 PTT Board Bottom Layer Position Mark Diagram.......... 37
Figure 15 KB-36C Schematic Circuit Diagram ............................................. 38
Figure 16 KBC-60Q Schematic Circuit Diagram .......................................... 39
Figure 17 PCB Layout 1 ................................................................................. 40
Figure 18 PCB Layout 2 ................................................................................. 41

PT6800 Service Manual
1
Chapter 1 Overview
1.1 Introduction
This manual applies to the service and maintenance of
PT6800 trunking portable radios, and is intended for use by
engineers and professional technicians that have been trained
by Kirisun. It contains all required service information for the
equipment. Kirisun reserves the right to modify the product
structure and specifications without notice in order to enhance
product performance and quality. You can also log on our
website www.kirisun.com to download the latest service
manual or contact your local dealer or us.
Please read this manual before repairing the product.
1.2 Safety Precautions
* Electromagnetic Energy Radiation
Radios will generate and radiate electromagnetic energy
during transmit mode.
The safety design of Kirisun radios complies with national
and international standards.
In order to obtain best performance, and to guarantee that
the electromagnetic radiation does no harm to you, always keep
the radio vertical to the ground and make sure that the
microphone is 2-5cm from your mouth while using the radio.
* Explosive Atmosphere
It’s prohibited to use or repair the radio in the following
places:
Hospital, health center, airport, or where “TURN OFF
TWO-WAY RADIO” signs have been posted.
Any area with a potentially explosive atmosphere (e.g.
orlop deck of the ship, storage and transportation equipment for
fuel and chemical etc.)
Any place near blasting sites or area with electrical blasting
cap.
It is also prohibited to change or charge the battery in any
area with a potentially explosive atmosphere.
* Antenna
If the antenna has been damaged, do not use the radio.
Damaged antenna may cause light burning on skin.
* Replacement Parts
All components used for repair should be supplied by
Kirisun.
Components of the same type available on the market are
not surely able to be used in this product and we do not
guarantee the quality of the product using such components.
If you want to apply for any component from Kirisun,
please fill in an application form as below.
e.g.
Component Application Form
Radio
Model Component Position Mark
Model/
Specifications Parts No. Qty
PT6800-01 FET Q3 RD01MUS1 105-RD01MU-R01 1
PT6800-01 Triode Q49 2SC5108（Y）104-SC5108-001 1
1.3 Service
All the Kirisun products are subject to the service warranty.
After-sales service will be provided, and the length of
warranty is stated by Kirisun. The radio and its accessories are
all in the warranty. However, in one of the following cases,
charge free service will not be available.
* No valid warranty card or original invoice.
* Malfunction caused by disassembling, repairing or
reconstructing the radio by users without permission.
* Wear and tear or any man-made damage such as mechanical
damage, burning or water leaking.
* Product’s serial number has been damaged or the product
trademark is difficult to identify.
After the warranty expires, lifetime service is still available.
We also provide service components to service stations and
staffs.
Chapter 2 External View and Functional
Keys
2.1 External View and Functional Keys
See Figure 2.1.
Figure 2.1
A. LED Indicator
Lights red while transmitting; lights green while receiving;

PT6800 Service Manual
2
flashes red while in low battery power.
B. On/Off/Volume Control Knob
Rotate clockwise till a sound of click is produced to turn on
the radio; and rotate anticlockwise till a sound of click is
produced to turn off the radio. Rotate this knob to adjust the
volume while the radio is on.
C. Rotary Encoder
Rotate this knob to select your desired call address or
features for setting.
D. Antenna
E. Emergency Button
Press it to enable the “Emergency Call” function.
F. Clear Button
Press to return to Trunking Mode while in Conventional
Mode, or to end a call.
G. PTT (Push-To-Talk) Button
Press to call or transmit voice.
H. Redial/Monitor Button
Press to redial a number or monitor the channel.
I. “ ”Key
Press to enter the Menu Mode.
J. “ ” Key
Scroll upwards to view the previous page.
K. “ ” Key
Scroll downwards to view the next page.
L. “ ” Key
Press to view status messages or data messages.
M. Numeric Keypad
Press to input the call address or dial a number.
N. Universal Connector
Connect to earphone or optional speaker/microphone.
2.2 Display Screen
Icon Description
Indicates the signal strength.
SVC Appears when a control channel is found. Flashes while
the radio is hunting for a control channel. (Trunking
Mode only)
MON Appears while you are monitoring a channel by pressing
the Monitor button. (Conventional Mode only)
SCN Appears while you are scanning. (Conventional Mode
only)
Lo Appears when the transmitting power is low.
Appears when you are in home system, and disappears
when in roaming. (Trunking Mode only)
Appears when there is new data received, including
voice message, digital data message and missed calls.
(Trunking Mode only)
Appears when you are in roaming. (Trunking Mode
only)
Appears when the keypad is locked.
Appears when the Rotary Encoder is locked.
Appears when the setting is not All Mute, and the ring
alert function is active.
Indicates the current battery power level, and flashes
when the battery power is low.
Chapter 3 Mode Introduction
3.1 Mode Introduction
Mode Function How to Enter
Trunking
Mode
Press the Clear Button to return to
Trunking Mode while in
Conventional Mode.
User
Mode Conventional
Mode
For normal use.
Press “ ” key to enter
Conventional Mode while in
Trunking Mode. Or press the
com
b
ination keys set in PC
software to switch between the
two modes.
Panel Test Mode
Used by the
dealer to check
the fundamental
characteristics.
Press and hold “ ”key while
turning the radio power ON.
Panel Tuning Mode
Used by the
dealer to tune the
radio.
Press and hold “ ” key while
turning the radio power ON.
Version Information
Mode
Used to check
the version.
Press and hold “ ” key while
turning the radio power ON.
PC Test Mode
Used to tune the
radio by PC.
Run KSP6800 programming
software. Click “Program” in the
main menu, and then click “Test
Mode” in the pull-down menu.
3.2 Panel Test Mode
Please refer to Chapter 7 Adjustment.
3.3 Panel Tuning Mode
Please refer to Chapter 7 Adjustment.
3.4 PC Test Mode

PT6800 Service Manual
3
Please refer to Chapter 7 Adjustment.
Chapter 4 Circuit Description
4.1 Preface
This portable radio is FM trunking portable equipment.
4.2 Frequency Configuration
Figure 4.1 Frequency Configuration
The receiver adopts double mixing. The first IF is
51.65MHz and the second IF is 450KHz.
The first local oscillator signal of the receiver is generated
by the frequency synthesizer. The second local oscillator signal
is generated by quadrupler X1.
The transmitter signal is directly produced by the frequency
synthesizer.
The reference frequency of the frequency synthesizer is
provided by TCXO.
4.3 Principle of Receiver (RX)
Figure 4.2 Principle of Receiver
Front End
The signal coming from the antenna passes through the
RX/TX switch circuit (D1, D39, D7, and D8), and passes
through a BPF consists of two LCs to remove unwanted
out-of-band signal, and then is routed to the low noise amplifier
(LNA) consists of Q18 and its peripheral components where it
is amplified.
Output signal from the LNA passes through a BPF consists
of three LCs to further remove unwanted out-of-band signal,
and then goes to the first mixer (Q19).
AGC Circuit
AGC circuit, which consists of Q17 and its peripheral
circuit, will work to reduce the gain of Q18 only when the input
signal is oversize.
First Mixer
The receiving signal from LNA is mixed with the first local
oscillator signal from the frequency synthesizer to produce the
first IF signal (51.65MHz).
IF Circuit
The first IF signal passes through crystal filter (XF1) to
remove the adjacent channel signal and signal outside the
adjacent channel. Then the filtered signal is amplified by the
first IF amplifier (Q20), and is routed to the IF processing IC
(IC4, TA31136).
IF IC consists of the second mixer, IF amplifier, limiter,
discriminator, noise amplifier, and audio low pass filter.
Signal (12.8MHz) from X1 is multiple-amplified by Q15
and its peripheral circuit to produce the second local oscillator
signal (51.2MHz). Then the second local oscillator signal
(51.2MHz) is mixed with the first IF signal (51.65MHz) in IC4
to generate the second IF (450KHz). And then the second IF
signal is amplified and limited in IC4, filtered in the ceramic
filter (CF1 or CF2, 450KHz), and demodulated in IC4. After
that, the demodulated signal is routed to the audio circuit to
output audio signal.
The selection circuit of the second IF filter consists of CF1,
CF2, D18, D19 and the peripheral circuit. When the radio is set
to wideband, CF2 is put through and takes effect, while CF1 is
cut off; when the radio is set to narrowband, CF1 is put through
and takes effect, while CF2 is cut off.
Squelch Circuit
The demodulated signal from IC4 is sent to the internal
noise amplifier in IC4. Then the resulting signal is further
amplified in Q21 and demodulated in D22, and then the
resulting DC level is routed to the MCU squelch control circuit.
This voltage is in inverse proportion to the input signal.
4.4 Principle of Transmitter (TX)
TX PowerAmplification

PT6800 Service Manual
4
Figure 4.3 Principle of Power Amplifier and Antenna Switch
The modulated RF signal from VCO is amplified in Q2, Q4,
Q59, Q5, and Q3, and is routed to Q1 for power amplification.
Grid bias of Q1 and Q3 is controlled by the APC circuit.
Through changing the grid bias voltage, the Tx output power
can be controlled conveniently.
APC (Automatic Power Control) Circuit
R57, R65, and R66 are used to test the power amplification
current. IC3A is the sampling amplifier for the power
amplification current. IC3B is the power comparator amplifier.
If the Tx output power is too high, the power amplification
current and IC3A output will increase; IC3B output voltage will
decrease, so the bias voltage of Q1 and Q3 will also decrease,
which causes the Tx output power to be lowered, and vice versa.
Thus the output power of Tx can keep stable under different
working conditions.
MCU can set the power through changing the voltage input
to IC3B.
4.5 Principle of Frequency Synthesizer
Figure 4.4 Frequency Synthesizer
The radio adopts PLL type frequency synthesizer.
The frequency synthesizer consists of reference oscillator,
voltage control oscillator (VCO), programmable divider, phase
comparator, and low pass filter.
Tx VCO unit consists of Q6, D2, D4, D5, and D6. D9 is the
modulation circuit of Tx VCO.
Rx VCO unit consists of Q11, D11, D12, D13, and D14.
IC2 (ADF4111) is the PLL integrated circuit, which consists
of programmable reference divider, programmable divider,
phase comparator, and charge pump.
The low pass filter consists of R43 and C96.
The reference frequency is provided by X1 (TCXO,
12.8MHz).
The reference frequency from TCXO (Temperature
Controlled Crystal Oscillator) is divided by the programmable
reference divider in IC2 to produce reference frequency of
5KHz or 6.25KHz (determined by the preset channel frequency
and is controlled by MCU).
The oscillation frequency from VCO goes to IC2 where it is
divided by the programmable divider and is then compared
with the reference frequency to obtain the error signal. The
signal is then filtered by a low pass filter, and is routed to VCO
to change the oscillation frequency of the VCO, enabling the
frequency to reach the set value. Then the VCO is locked.
Unlock detection: When PLL is unlocked, Pin 14 of IC2
will output the low level signal to MCU. Then MCU prohibits
the Tx from transmitting and makes an alert tone.
Q13 and other relevant circuits are used to switch the low
pass filters.
4.6 Audio Processing Circuit
Figure 4.5 Audio Processing
IC6 (AK2346) is a special voice processing chip, which is
provided with functions of amplification, filtering,
pre-emphasis, de-emphasis, scrambling, companding, MSK
MODEM, etc. Most of the radio’s voice processing is done by
IC6.
MIC Signal Processing
The voice signal coming from the MIC passes through the
AGC circuit, and goes to IC24. One branch of the signal is
routed to IC24B (VOX circuit) for amplification, and then goes
to D35, where it is processed and turned into DC voltage, and
then sent to MCU for processing. The other branch of the signal
is routed to IC24A for amplification, and then goes to pin3 of
IC6, where it is amplified, filtered, companded (optional),
pre-emphasized, scrambled (optional), and limited, and then is
output from pin7 of IC6. After that, the resulting signal is sent
to VCO for modulation together with CTCSS/DCS. The 2T/5T
signal is input to pin6 of IC6. After being limited and amplified,
it is then output from pin7 of IC6, and is routed to VCO for
modulation.
RX Audio Signal Processing
Voice signal output from IC4 is divided into two parts. One
branch of the signal is routed to the low pass circuit consists of
IC5 and other components, where it is amplified and filtered (to
remove the voice signal) to obtain more purified CTCSS/DCS

PT6800 Service Manual
5
signal, which is then sent to MCU for processing. The other
branch of the signal is routed to pin23 of IC6. After being
amplified and filtered, the signal is divided into two branches.
One branch (DTMF/2T/5T signals) is output from pin21 of IC6.
The DTMF/2T/5T signals passes through the high pass circuit
consists of Q30, Q31, and other components to remove the
subaudio signal. The DTMF signal goes to IC10 (HT9172
special DTMF decoding chip) to be decoded, and then is sent to
MCU for processing. The 2T/5T signal goes to IC1, where it is
filtered and reshaped, and then is routed to MCU for processing.
The other branch (voice signal) is scrambled, de-emphasized,
and companded, and is output from pin18 of IC6. Then the
resulting signal is input to pin19 of IC6. After being buffered
and amplified, it is then output from pin20 of IC6.
IC13 is a voice memory chip, which is stored with voices of
channel indication etc. Once the rotary encoder is switched, the
speaker will announce the current channel number. User can
press the preprogrammed “Voice Alert” key to repeat the
current channel number.
After the RX audio signal, voice alert signal, 2T/5T/DTMF
signal, alert tone signal, and emergency alarm signal join
together, they are amplified by audio power amplification IC9,
and then drive the speaker.
Impedance of the speaker: 16
Note:
* None of the terminals of the speaker should be grounded.
* The emergency alarm sound has no volume limit.
4.7 Power Supply
The radio adopts 7.2V battery as power supply. The Tx
power amplification circuit (Q1 and Q3) and the Rx audio
power amplifier (IC9) directly adopts the battery as power
supply. Power of other circuits is supplied by the regulated
voltage (5V).
Q40 and Q45: 5V low dropout, micro-power regulator.
Q43: 5T switch, controlled by MCU.
5T: Supplies power for front end of Tx.
Q39: 5R switch, controlled by MCU.
5R: Supplies power for RF amplifier, mixer, IF processing
unit, and audio signal processing unit etc. of Rx.
Q44: 5C switch, controlled by MCU.
5C: 5V power supply under SAVE control. Supplies power
for frequency synthesizer.
4.8 MCU Unit
MCU unit controls the operation of each unit of the radio so
that all functions can be realized.
Communicate with external PC.
Access the status data of the radio.
Control the PLL to generate Rx and Tx local oscillator
frequencies.
Obtain status parameters of current channel.
Control status of LED indicator.
Control power supply for each unit.
Check the actions of each functional key.
Generate CTCSS signal.
Generate DCS signal.
Generate power control signal.
Perform CTCSS decoding.
Perform DCS decoding.
Testandcontrol the squelch.
Control content of voice alert.
Memory (E2PROM, AT24C256):
The memory is stored with channel data, CTCSS/DCS data,
other data for function setting, and parameter adjusting data of
the radio.
CTCSS/DCS Signal Encoding and Decoding
The CTCSS/DCS signal (output from pin24 and pin28,
PWM wave) generated by MCU is routed to VCO and TCXO
respectively for modulation.
The CTCSS/DCS signal from the receiver is decoded by
MCU. MCU checks if the CTCSS/DCS signal in the receiving
signal matches the preset CTCSS/DCS of the radio, and
determines whether to open the speaker or not.
CTCSS Signal
CTCSS (Continuous Tone Control Squelch System) is a
squelch control system which is modulated on carrier and is
guided by a continuous subaudio signal. If CTCSS is set, the
communication between the transmitting and receiving radios
can be realized only when the two radios has set the same
CTCSS. In doing this, disturbance from other signals can be
avoided.
PT6800 has 39 groups of standard CTCSS frequencies for
your selection. See table 4.1.
CTCSS signal is generated by MCU (PWM waveform), and
is passed through low pass filter consists of RC to remove high
frequency component (above 300Hz). Then the resulting signal
is routed to VCO for modulation.
Table 4.1 CTCSS Frequencies

PT6800 Service Manual
6
No. Frequency
[Hz]
No. Frequency
[Hz]
No. Frequency
[Hz]
No. Frequency
[Hz]
1 67.0 11 94.8 21 131.8 31 186.2
2 69.3 12 97.4 22 136.5 32 192.8
3 71.9 13 100.0 23 141.3 33 203.5
4 74.4 14 103.5 24 146.2 34 210.7
5 77.0 15 107.2 25 151.4 35 218.1
6 79.7 16 110.9 26 156.7 36 225.7
7 82.5 17 114.8 27 162.2 37 233.6
8 85.4 18 118.8 28 167.9 38 241.8
9 88.5 19 123.0 29 173.8 39 250.3
10 91.5 20 127.3 30 179.9
DCS Signal
DCS (Digital Code Squelch), which is used to control the
squelch, is a series of continuous digital codes modulated on
carrier together with voice signal. If DCS is set, the speaker can
be opened only when the radio receives signal with the same
DCS, so disturbance of unwanted signals can be avoided.
PT6800 has 83 standard codes (inverted and non-inverted)
for your selection. See table 4.2.
DCS signal is generated by MCU (PWM waveform). It
passes through the low pass filter consists of RC to remove the
high frequency components (above 300Hz). Then the resulting
signal is routed to VCO and TCXO for modulation, with HF
components of the DCS signal being modulated by VCO, and
the LF components of the DCS signal being modulated by
TCXO.
The DCS signal coming from the receiver is routed MCU
for decoding. MCU checks if the DCS code in the received
signal matches the preset DCS of the radio, and determines
whether to open the speaker or not.
Table4.2DCScodes
023 114 174 315 445 631
025 115 205 331 464 632
026 116 223 343 465 654
031 125 226 346 466 662
032 131 243 351 503 664
043 132 244 364 506 703
047 134 245 365 516 712
051 143 251 371 532 723
054 152 261 411 546 731
065 155 263 412 565 732
071 156 265 413 606 734
072 162 271 423 612 743
073 165 306 431 624 754
074 172 311 432 627
4.9 Semiconductor Data
MCU Description
Table 4.3 Description for Ports of Microprocessor (M30620)
No. I/O Port Name Function
1 O VCCN PLL reference frequency adjust
2 O TONEO 2T/5T/DTMF/BEEP signal output
3 I TONEI 2T/5T signal input
4 O E-SDA E2PROM data line
5 O E-SCL E2PROM clock line
6 - C-BYTE GND
7 - C-CNVSS GND
8 O SHIFT Clock beat shift H: Clock beat shift
9 O E-TEST E2PROM write protect pin H: Not writable L: Writable
10 I RESET Reset pin
11 O XOUT Clock output pin
12 - VSS GND
13 I XIN Clock input pin
14 - VCC 5V power supply
15 - CMMI GND
16 I INTO Power down detect pin
17 O A-RDT AK2346 control pin
18 O A-TCLK AK2346 control pin
19 O A-SCLK AK2346 control pin
20 O A-DI/O AK2346 control pin
21 O A-TDATA AK2346 control pin
22 O A-DIR AK2346 control pin
23 - NC -
24 O CTCSS VCO CTCSS/DCS output pin (to VCO for modulation)
25 O PLL-LP PLL - low pass filter toggle switch
H: Switch above center frequency point
26 O PC/TV Power control or Rx pass band tuning voltage control
27 - NC -
28 O CTCSS
TCXO
CTCSS/DCS output pin (to TCXO for modulation)
29 O C-TXD1 Serial data output, communicate with PC
30 O C-RXD1 Serial data input, communicate with PC
31 - C-CLK1 GND
32 - NC -
33 - ICA -
34 O PABC Power control for final power amplifier H: Transmitting
35 O APC2 SW Power amplifier control switch H: Transmitting
36 O APC1 SW Power amplifier control switch L: Transmitting
37 O RX SW Rx VCO power switch L: Receiving
38 O TX SW Tx VCO power switch L: Transmitting
39 - C-HOLD GND
40 I PLL-UL PLL unlock detect pin
41 O PLL-STB PLL enable pin
42 O PLL-DATA PLL data pin
43 O PLL-CLK PLL clock pin
44 - C-VCC Connect to power supply
45 O MAX AF
SW
Max. volume control L: Max. volume
46 O GREEN Green LED H: ON
47 O RED Red LED H: ON
48 O 5TC 5T control switch L: 5T is 5V
49 O 5RC 5R control switch L: 5R is 5V
50 O 5CC Battery save control switch L: 5C is 5V
51 O W/N N Wideband/Narrowband-Narrowband H: Narrowband
52 O W/N W Wideband/Narrowband-Wideband H: Wideband
53 O AFCO AF power amplifier control H: Amplifier works
54 O RX MUTE Rx mute control L: Mute
55 I W-BUSY Voice announcing chip busy signal detect H: Busy

PT6800 Service Manual
7
56 O W-DATA Voice announcing data signal
57 O W-SCLK Voice announcing clock signal
58 O W-MUTE Voice announcing mute control L: Mute
59 O S-SCK -
60 - ACC 5V power supply
61 O S-SI -
62 - VSS GND
63 O S-SO -
64 O S-CS -
65 - - -
66 I PTT PTT key input L: Transmitting
67 I H-D3 DTMF data input
68 I H-D2 DTMF data input
69 I H-D1 DTMF data input
70 I H-D0 DTMF data input
71 I H-DV DTMF data input
72 I DN Encoder switch signal
73 I UP Encoder switch signal
74 O L-AO LCD control signal
75 O L-AO LCD control signal
76 O L-AO LCD control signal
77 O L-AO LCD control signal
78 O L-AO LCD control signal
79 I/O K1 Keyboard signal
80 I/O K1 Keyboard signal
81 I/O K1 Keyboard signal
82 I/O K1 Keyboard signal
83 I/O K1 Keyboard signal
84 I/O K1 Keyboard signal
85 I/O K1 Keyboard signal
86 I/O K1 Keyboard signal
87 O LAMP Backlight control signal H: ON
88 I BATT Battery voltage detect
89 I RSSI Received signal strength indication detect
90 I BUSY Noise level detect
91 I VOX Voice control level detect
92 I
CTCSS/DCS
IN
CTCSS/DCS signal input
93 I PF Programmable button input
94 - AVSS GND
95 I MANDOWN MANDOWN signal input L: Valid
96 - VREF Connect to power supply
97 - AVCC Connect to power supply
98 O VOX SW VOX power control L: VOX enabled H: VOX disabled
99 O MIC MUTE MIC mute switch L: Mute
100 O HPF PC High pass power control L: Scramble enabled H:
Scramble disabled
Table 4.4 Function Description of Semiconductor Components
Position
Mark Model Function Description
IC11 PST9140NR MCU reset circuit
IC14 TC75W51FU MIC amplification, limitation, and filtering
IC2 ADF4111 Frequency synthesizer
IC3 NJM2904 APC, voltage comparison, driving
IC4 TA31136
Rx second local oscillator, second IF
amplification, limitation, demodulation, and
noise amplification
IC5 NJM2902
Rx demodulation signal amplification and
filtering
IC6 AK2346 Audio processing chip
IC7 M30620 MCU
IC8 AT24C256
E2PROM, stores channel frequency data,
function setting parameters, and adjusting status
parameters
IC9 TDA8541 Rx audio power amplifier
RD07L RQA0002 Tx final power amplifier
Q10 DTC144EUA APC control switch
Q11 2SK508NV Rx VCO oscillator circuit
Q12 DTA144EE APC output switch
Q12 DTA144EE APC control switch
Q13 2SC4116 PLL low pass switch
Q14 2SC4617 VCO power supply filter
Q15 2SC5108 Rx second oscillator frequency multiplier circuit
Q16 DTC144EE APC control switch
Q17 2SK1829 Rx high power amplifier gain control switch
Q18 3SK318 Rx high power amplifier
Q19 3SK318 First mixer
Q2 2SC5108 VCO buffer amplifier
Q20 2SC5108 First IF amplifier
Q21 2SC4617 Rx noise amplifier
Q22 DTC144EE Red LED drive
Q23 DTC144EE Wideband-Narrowband noise toggle switch
Q24 DTC144EE Green LED drive
Q25 DTA144EE Wideband-Narrowband discriminator toggle
switch
Q26 DTA123JE 2T high pass filter control switch
Q29 2SK1824 2T high pass filter control switch
Q3 RD01MUS1 Tx power amplifier drive
Q30 2SC4617 2T high pass filter circuit
Q31 2SC4617 2T high pass filter circuit
Q32 DTC144EE Beat control switch
Q33 2SK1824 Rx audio mute switch
Q34 2SK1824 Rx audio output switch, disconnect when
emergency alarm ON.
Q35 DTC144EE Audio power amplifier control switch
Q36 DTA144EE MIC amplification unit power switch
Q37 2SK1824 Voice alert switch
Q38 2SA1586 External PTT detect switch
Q39 ST2301 5R switch
Q4 2SC5108 VCO buffer amplifier
Q40 XC6024B502MR 5V regulated voltage output
Q41 2SC4116 MIC AGC control switch
Q42 DTC144EE External PTT detect switch
Q43 ST2301 5T switch
Q44 DTA123JE 5C switch
Q45 XC6024B502MR 5V regulated voltage output
Q47 2SA1586 MIC AGC control switch
Q48 ST2302 External speaker control switch
Q49 2SC5108 Tx first amplifier
Q5 2SC3356 Tx second amplifier
Q51 2SK1824 Rx audio output switch, connect when
emergency alarm ON.
Q6 2SK508NV Tx VCO oscillator circuit
Q7 DTA143TE Tx VCO control switch
Q8 2SC5108 VCO buffer amplifier
Q9 DTA143TE Rx VCO control switch
Table 4.5 Function Description of Diodes
Position
Mark Model Function Description
D1 HVC131 Tx antenna switch diode
D10 MA2S111 Unlock detect diode
D11 HVC376
Rx VCO oscillation varactor diode
D12 HVC376 Rx VCO oscillation varactor diode
D13 HVC376 Rx VCO oscillation varactor diode
D14 HVC376
Rx VCO oscillation varactor diode
D15 HZU5ALL APC output voltage limiting diode
D16 MA2S111 VCO power filtering acceleration diode
D17 HSC277 VCO output switch
D18 DAN222
Rx second IF filter wideband-narrowband toggle
switch
D19 DAN222
Rx second IF filter wideband-narrowband toggle
switch

PT6800 Service Manual
8
D2 HVC376
Tx VCO oscillation varactor diode
D21 HVC355B
Rx bandpass filter varactor diode
D22 MA742
Noise demodulation
D23 HVC355B
Rx bandpass filter varactor diode
D26 LED green
Receiving indication
D27 HVC376B Rx bandpass filter varactor diode
D28 LED red
Transmitting indication
D28 HVC376B Rx bandpass filter varactor diode
D29 HVC376B Rx bandpass filter varactor diode
D3 HSC277 VCO output switch
D30 HVC376B Rx bandpass filter varactor diode
D31 LED green Receiving indication
D35 MA742 VOX detect diode
D36 MA742 MIC AGC detect diode
D37 MA742 MIC AGC detect diode
D39 HVC131 Tx antenna switch diode
D4 HVC376 Tx VCO oscillation varactor diode
D40 HVC376B Rx bandpass filter varactor diode
D5 HVC376 Tx VCO oscillation varactor diode
D6 HVC376 Tx VCO oscillation varactor diode
D7 HSC277 Antenna toggle switch
D9 1SV278 Tx VCO modulation diode
Table 4.6 Features of Crystal Filter XF1
Item Rated Value
Nominal center frequency 51.65MHz
Pass bandwidth ±7.5kHz or higher
40dB stop bandwidth ±20.0kHz or lower
Pulse 1.0dB or lower
Insertion loss 3.0dB or lower
Guarantee attenuation 80dB or higher
Terminal impedance 330
Table 4.7 Performances and Features of CF1 LTWC450H
Item Rated Value
Nominal center frequency 450kHz
6dB bandwidth ±3.0kHz or higher
50dB bandwidth ±9.5kHz or lower
Pulse 2.0dB or lower
Insertion loss 6.0dB or lower
Guarantee attenuation 47.0dB or higher
Terminal impedance 1.5k
Table 4.8 Performances and Features of CF1 LTWC450F
Item Rated Value
Nominal center frequency 450kHz
6dB bandwidth ±6.0kHz or higher
50dB bandwidth ±12.5kHz or lower
Pulse 2.0dB or lower
Insertion loss 6.0dB or lower
Guarantee attenuation 47.0dB or higher
Terminal impedance 1.5k
Chapter 5 Function Description and
Parameter Setting
5.1 Characteristics
1) The radio conforms to the MPT1327 signaling protocol
standard, applies to a variety of base station systems including:
Tait, TaiHe, WanGe, QiaoHang etc., and supports various call
methods.
2) The radio conforms to the MPT1343 standard.
3) The radio is provided with special functions of remote killing,
reactivating, and dynamic grouping.
4) 32 conventional channels, standard CTCSS/DCS signaling,
BCL, TOT, and scan function.
5) 16 test frequencies and parameter indications, which are
convenient for the dealer to test the radio.
6) Power, deviation, sensitivity and other parameters are
programmed at the factory.
5.2 Trunked Features
1) Trunking signaling
The radio conforms to MPT1327 trunking signaling and
MPT1343 standard.
2) Hunt
64 control channels can be programmed for the radio, and
the radio will hunt for a control channel automatically.
3) Trunking calls
The following calls can be performed by the radio:
inter-prefix individual call, inter-prefix group call, inter-fleet
individual call, inter-fleet group call, voice call, status message
call, short data message call, conference call, broadcast call,
priority call, emergency call, PABX call, PSTN call, NPD
transfer, own call diversion, third party call diversion, include
call, ALLI call, network operator service call, technician call,
don’t disturb facility, queue incoming call, etc.
4) Emergency call
Press the orange “Emergency Button” to send an emergency
call in case of emergency.
5) Dynamic grouping
Dynamic grouping function allows the base station to group
units as a new team by remote control.
6) Remote killing
The base station can give remote killing order to the lost or
stolen radio to prohibit its operation.
7) Reactivating
The base station can give reactivating order to the remote
killed radio so that it can return to normal operation.
8) Missed calls
Missed calls can be displayed, and the status of the missed
calls can be stored.
9) Contact list
Large memory of 200 contacts.
10) Status message

PT6800 Service Manual
9
Content of status messages can be programmed by PC
software. Alert tone sounds while messages are received, and
the status message can be checked by the user.
11) Redialing
10 groups of dialed number can be stored in the radio. Press
the Redial Button, the dialed number can be displayed on LCD,
select the number you want and press PTT or “#” key to call.
12) Don’t disturb
This function allows the radio to refuse voice calls, status
message calls, and short data calls.
5.3 Conventional Features
1) CTCSS/DCS
The dealer may have set CTCSS/DCS on channels of the
radio. In doing this, other irrelevant calls using the same
channel can be ignored. If a channel has set CTCSS/DCS, the
squelch can be opened only when the received signal has the
same CTCSS/DCS.
2) DTMF dialing
Input the number while pressing the PTT key. Then you can
hear DTMF sound from the speaker.
3) Busy channel lockout (BCL)
This function can prevent other radios on the same channel
from being interfered. When the channel is occupied, the radio
will prohibit transmitting signals.
4) Time-Out Timer (TOT, TOT pre-alarm, TOT-rekey, TOT
reset)
TOT is used to prevent any person from using a channel to
transmit for an extended period of time. If the continuous
transmission time is longer than the preset time limit, the radio
will make alarm tone and stop transmitting.
5) Channel scan
32 conventional channels can be set through PC
programming software, and the parameters on each channel can
be set, such as CTCSS/DCS encoding and decoding,
wideband/narrowband, BCL, high power/low power,
compander, channel name, etc. If signals are detected while in
channel scanning, the scanning will pause and the information
of the paused channel will be displayed.
5.4 General Features
1) Channel spacing
The channel spacing can be selected (12.5kHz/25kHz)
through PC programming software.
2) Signal strength display
The real time signal strength can be displayed on the screen.
3) Battery power display and low battery warning
The battery power can be displayed on the screen and when
the battery power is low, the battery indicator will flash to
warn.
5.5 Functional Parameter Setting
The radio’s functional parameters have been set before
leaving the factory. However, due to different requirements of
users, the radio’s trunked features, operating frequency,
channels, CTCSS/DCS, scan, and other function parameters
should be reset. Therefore, the company has specially designed
a set of Chinese/English programming software KSP6800 with
friendly interface, convenient operation and visualized display
for setting functional parameters of the radio.
Steps for setting the functional parameters of the radio by
computer are as follows:
A. Install KSP6800 on the computer.
B. Connect the radio to the COM port of the computer with
the special programming cable. Refer to the figure below.
Note: While connecting, make sure that the power of the
computer and the radio are both turned off.
C. Turn the computer power ON.
D. Turn the radio power ON.
E. Run the KSP6800 programming software by double
clicking its executive program.
F. Click “Program” in the main menu of KSP6800, and
click “Read from radio” in the pull-down menu to read
parameters of the radio to the computer; click “Write to radio”
in the pull-down menu to write parameters in the computer to
the radio.
G. The following parameters can be set by using KSP6800
according to requirements of the user:
1) Basic parameters of the system
2) System code
3) Channel parameters
4) Frequencies
5) Hunt option of control channel
6) Personalization
7) Call facilities
8) Call scope limit
9) Call address
10) Default call address
11) Contact list and relevant options
12) 5 digit dialed string
Computer
Programming cable
for PT6800 Radio