Kirisun PT4208 User manual

PT4208 Service Manual
1
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 higher than 20 dBm
(100mW).
Do not turn on the power 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 KSP4208 software.
Unauthorized Duplication of KSP4208 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..............................................................................................................2
Chapter 2 External View and Functional Keys ....................................................................2
Chapter 3 Circuit Description...............................................................................................3
Chapter 4 Mode Introduction ...............................................................................................9
Chapter 5 Assembly and Disassembly for Maintenance.................................................... 11
Chapter 6 Adjustment.........................................................................................................12
Chapter 7 Specifications.....................................................................................................16
Chapter 8 Troubleshooting .................................................................................................16
Chapter 9 KBC-70C Charger .............................................................................................17
Appendix 1 Abbreviations..................................................................................................18
Appendix 2 Electronic Parts List .......................................................................................18
Appendix 3 Structural Parts List ........................................................................................29
Appendix 4 Accessories .....................................................................................................31
Figure 1 PT4208 Block Diagram .......................................................................................32
Figure 2 PT4208 Schematic Circuit Diagram (420-470MHz) ..........................................33
Figure 3 PT4208 Main Board Top Layer Position Mark Diagram (420-470MHz)...........34
Figure 4 PT4208 Main Board Bottom Layer Position Mark Diagram (420-470MHz).....35
Figure 5 PT4208 Main Board Top Layer Position Value Diagram (420-470MHz) ..........36
Figure 6 PT4208 Main Board Bottom Layer Position Value Diagram (420-470MHz) ....37
Figure 7 PT4208 Main Board Top Layer Layout (420-470MHz) .....................................38
Figure 8 PT4208 Main Board Bottom Layer Layout (420-470MHz) ...............................39
Figure 9 PT4208 Schematic Circuit Diagram (136-174MHz) ..........................................40
Figure 10 PT4208 Main Board Top Layer Position Mark Diagram (136-174MHz).........41
Figure 11 PT4208 Main Board Bottom Layer Position Mark Diagram (136-174MHz)...42
Figure 12 PT4208 Main Board Top Layer Position Value Diagram (136-174MHz) ........43
Figure 13 PT4208 Main Board Bottom Layer Position Value Diagram (136-174MHz) ..44
Figure 14 PT4208 Main Board Top Layer Layout (136-174MHz) ...................................45
Figure 15 PT4208 Main Board Bottom Layer Layout (136-174MHz) .............................46
Figure 16 KBC-70C Schematic Circuit Diagram ..............................................................47
Figure 17 KBC-70C Top Layer Position Value Diagram ..................................................48
Figure 18 KBC-70C Top Layer Position Mark Diagram...................................................49
Figure 19 KBC-70C Bottom Layer Position Value Diagram ............................................50
Figure 20 KBC-70C Bottom Layer Position Mark Diagram.............................................51
Figure 21 KBC-70C Layout ...............................................................................................52

PT4208 Service Manual
2
Chapter 1 Overview
1.1 Introduction
This manual applies to the service and maintenance of
PT4208 series 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 Service Attentions
* Safety
Do not contact the antenna connector or PCB with your
skin directly.
Do not reverse the battery polarity.
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 and load
connection is completed.
If the antenna has been damaged, do not use the radio.
Damaged antenna may cause light burning on skin.
* Explosive Atmosphere
It’s prohibited to use or repair the radio in the following
places:
Hospital, health center, and airport.
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.
* 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
PT4208-02 FET Q3 RD01MUS1 105-RD01MU-R01 1
PT4208-02 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
restructuring 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
See Figure 1.
Figure 1
2.2 Functional Keys
1. LED Indicator
Lights red while transmitting; lights green while

PT4208 Service Manual
3
receiving; flashes red while in low battery power.
2. Channel Selector Knob
Rotate the knob to select channel 1-16.
3. On/Off/Volume Control Knob
Rotate clockwise to turn on the radio, and keep turning
to adjust the volume. To turn off the radio, rotate the knob
anticlockwise till a sound of click is produced.
4. PTT (Push-To-Talk) Key
Press the PTT key and talk to the microphone to send the
voice to the recipient.
5. Side Key 2 (Programmable key)
6. Side Key 1 (Programmable key)
7. Top Key (Programmable key)
8. Speaker/Microphone Jack
Jack for connecting external speaker or external
microphone to the radio.
Chapter 3 Circuit Description
3.1 Frequency Configuration
Figure 3.1 Frequency Configuration
The reference frequency of the frequency synthesizer is
provided by crystal oscillator X4 (TCXO, 16.8MHz). The
receiver adopts double mixing. The first IF is 49.95MHz 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 adopts the third harmonic
(50.4MHz) of the crystal oscillator X4 (TCXO, 16.8MHz).
Transmitter signal is directly produced by the frequency
synthesizer.
3.2 Principle of Receiver (RX)
Figure 3.2 Principle of Receiver
Front end
The signal coming from the antenna passes through the
RX/TX switch circuit (D1, D2, D4 and D5), and passes
through a BPF (C37, C227, L8, L15, C70, C126, D30, C218,
L9, C230, C128, D26, C217, L10, C229, C127 and D24) to
remove unwanted out-of-band signal, and is routed to the
low noise amplifier (LNA) consists of Q20 and its peripheral
components where it is amplified.
Output signal from the LNA passes through a BPF (L7,
C228, C47, D23, C219, L6, C182, C124, D22, C216, L5,
C132, C32 and D21) and goes to the first mixer (Q19).
PWM wave is output from pin 12 of the MCU. The wave
is filtered and rectified into adjustable voltage, which can
control the center frequency of the band pass filter through
changing capacity of the varactor diode (D21, D22, D23,
D24, D26 and D30).
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 (49.95MHz). Then the first IF
signal passes through crystal filter (XF1 and XF2) to remove
the adjacent channel signal and signal outside the adjacent
channel.
IF circuit
The first IF signal from the crystal filter is amplified by
the first IF amplifier (Q21), and is routed to the IF
processing IC (IC5, TA31136).
IF IC consists of the second mixer, second local
oscillator, IF amplifier, limiter, discriminator, and noise
amplifier.
The 16.8MHz frequency produced by TCXO (X4) is
multiple-amplified and then adopts the third harmonic
(50.4MHz) as the second local oscillator signal source. The
second local oscillator signal (50.4MHz) is mixed with the
first IF signal (49.95MHz) in IC5 to generate the second IF
(450kHz). And then the second IF signal is amplified and
limited in IC5, filtered in the ceramic filter (CF1, 450kHz),
and demodulated in IC5. After that, the demodulated signal
is routed to the audio circuit to output audio signal.

PT4208 Service Manual
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Figure 3.3 IF System
Audio signal processing
The voice signal processing circuit of the receiver
consists of IC6 and its peripheral circuits. After being
amplified in IC6-C, voice signal from IC5 is sent to IC4
(CTCSS signaling filtering circuit) and IC6-D respectively.
The signal is then amplified, deemphasized and filtered by
other units of IC6 to remove HF and LF components
contained in the audio frequency, with only voice
components within 300~3000Hz left. The resulting signal is
then routed to Q9 for amplifying. The amplified signal is
adjusted in volume potentiometer and then is routed to the
audio power amplifier (IC8).
Figure 3.4 Audio Processing of Receiver
Squelch circuit
The demodulated signal from IC5 goes to the selective
noise amplifier consists of noise amplifier within IC5, C211,
R99, R100, C107 and R94 to remove the noise component.
The resulting signal is then amplified in Q7 and
demodulated in D17 and is routed to the MCU. MCU
identifies level of the noise and controls the squelch.
Audio power amplifier
The audio power amplifier circuit consists of IC8 and its
peripheral components.
The received audio signal, voice alert signal, alert tone
signal and warning tone signal are collected and pass
through the audio amplifier where it is amplified and output
to drive the speaker. The warning tone has no volume
limitation.
When AFCO is in high level, Q35 turns on, IC8 starts to
operate, and the speaker sounds. Speaker impedance: 16.
Q38: RX audio signal switch
Q51: Warning tone switch
Q25: Alert tone switch
CTCSS signal filtering
Demodulated audio signal from IC5 may contain CTCSS
(Continuous Tone Control Squelch System) or DCS (Digital
Code Squelch) signal. The spectrum components of
CTCSS/DCS are within 67-250Hz. The filtering circuit
consists of IC4 can remove signals outside the CTCSS/DCS
spectrum, which enables the MCU to decode CTCSS/DCS
more accurately.
3.3 Principle of Transceiver (TX)
TX power amplification
Figure 3.5 Principle of Power Amplification and Antenna
Switch
The modulated RF signal from VCO is amplified in Q2,
Q3 and Q12, and is routed to Q11 for power amplification.
Grid bias of Q11 and Q12 is controlled by the APC
circuit. Through changing the grid bias voltage, the Tx
output power can be controlled conveniently.
APC (Automatic Power Control)
Figure 3.6 APC Circuit
R167, R168 and R169 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 Q11 and
Q12 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

PT4208 Service Manual
5
input to IC3B.
Tx voice signal processing
TCXO
VCO
MCU
CTCSS/DCS
MIC
MIC Amp Pre-Emphasis
IC7A IC7B
IC7C,IC7D
Figure 3.7 Audio Circuit of Tx
The Tx voice signal processing circuit consists of IC7
and its peripheral components. After being amplified, limited
and filtered, the voice signal from MIC is routed to VCO for
modulation together with CTCSS/DCS signal.
The AGC circuit is consisting of D13, D308 and Q24.
When signal from MIC is too large, the AGC circuit will
lower the signal strength to make sure that no distortion
happens to the signal.
Q34 is the power switch of the voice processing circuit.
It is controlled by MCU. Power supply of IC7 will be turned
on when the radio is transmitting.
J2 is the jack for external MIC. When using external
MIC, the internal MIC will be turned off automatically. But
the internal PTT is still effective.
3.4 Principle of Frequency Synthesizer
1
Nr
1
N
Control Circuit Charge
UL
Detect
Pump
TCXO
DCS Mod
Freq Adj
to MCU VCCN
Data
CK
LE
to MCU
VCO
RX
TX
D3,D6
Q4
Q5
MOD in
Figure 3.8 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.
Rx VCO unit consists of Q14, L30, C120, C88, C142,
C180, D8 and D9. Tx VCO unit consists of Q15, L51, C121,
C137, C206, C194, D10 and D11. D12 is the modulation
circuit of VCO.
IC1 (MB15E03) is PLL integrated circuit, which consists
of programmable reference divider, programmable
swallowing divider, phase comparator, and charge pump.
The low pass filter consists of R244, C193, R202, R40,
C207, R141, C205, R2 and C204. The reference frequency is
provided by X4 (TCXO, 16.8MHz).
The reference frequency from TCXO (Temperature
Controlled Crystal Oscillator) is divided by the
programmable reference divider in IC1 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 IC1 where
it is divided by the programmable swallowing 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.
N=F
VCO/FR
N: Times of frequency division
F
VCO: Oscillation frequency of VCO
F
R: Reference frequency
Unlock detection: When PLL is unlocked, Pin 14 of IC
will output the low level signal to MCU. Then MCU
prohibits the Tx from transmitting and makes an alert tone.
Q6: Power filter, which provides more purified power for
PLL to reduce noise of the frequency synthesizer.
3.5 Voice Alert Circuit
The radio is provided with voice alert function, which is
especially useful at night or in dark environment.
IC15 is a voice memory chip, which is stored with voices
of channel indication etc. Once the channel selector knob is
switched, the speaker will announce the current channel
number. User can press the preprogrammed “Voice Alert”
key to repeat the current channel number.
If voice alert function is enabled, the speaker will
announce the current channel number once the “Voice Alert”
key is pressed under standby mode. You can switch the voice
type by pressing and holding the “Voice Alert” key while
rebooting the radio. Do it repeatedly to switch the voice type
in the order of “Chinese Male-English Male-Chinese
Female-English Female-No Alert”.
3.6 Power Supply
The radio uses 7.4V, 1700mAh Li polymer battery. The
Tx power amplification circuit (Q11 and Q12) and the Rx
audio power amplifier (IC8) directly adopt the battery for
power supply. Power of other circuits is supplied by 5V
regulated voltage.

PT4208 Service Manual
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IC12: 5V, low dropout, micro-power regulator, which
supplies 5V power with large current for the radio together
with Q10 and Q30.
Q29: 5T switch, which is controlled by MCU.
5T: Supplies power for front end of Tx.
Q31: 5R switch, which is controlled by MCU.
5R: Supplies power for RF amplifier, mixer, IF
processing unit, and audio signal processing unit etc. of Rx.
Q32: 5C switch, which is controlled by MCU.
5C: 5V power supply under SAVE control. Supplies
power for frequency synthesizer.
3.7 MCU Unit
EEPROM
D/A
chananl
SW
PTT MONI
ALARM
PF1
CTCSS/DCS IN
SQL BATT VCCN
CTCSS/DCS OUT
BEEP
LE DATA CK
to PLL
VIOCE CHIP
TX/RX CONTROL
RXD TXD
to PC
UL
5TC
5RC
SAVE
APC CONTR
SHIFT
IC9
IC10
MCU
Figure 3.9 Principle of 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, AT24C08):
The memory is stored with channel data, CTCSS/DCS
data, other data for function setting, and parameter adjusting
data.
CTCSS/DCS signal encoding and decoding:
The CTCSS/DCS signal (output from pin 12) generated
by MCU is filtered by R155, R156, C242 and C243. Then
the resulting signal is divided into two parts and sent to VCO
and TCXO respectively for modulation.
The CTCSS/DCS signal from the receiver is decoded by
MCU (pin 49). MCU checks if the CTCSS/DCS signal in the
receiving signal matches the preset value of the radio, and
determines whether to open the speaker or not.
Power adjustment:
Output from pin 42 of the MCU passes through
integrating filter (R161, C317, R206, and C318), and is
routed to the APC unit to control the output power of the
transmitter.
CTCSS signal
CTCSS (Continuous Tone Control Squelch System) is a
squelch control system which is modulated on carrier and is
guided by a continuous sub-audio 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 frequency. In doing this, disturbance from
other signals can be avoided.
PT4208 has 39 groups of standard CTCSS frequencies
for your selection. See table 3.1.
The CTCSS signal is generated by MCU, and is passed
through low pass filter consists of RC to remove high
frequency components (above 300Hz). Then the resulting
signal is routed to VCO for modulation.
Table 3.1 CTCSS Frequencies
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

PT4208 Service Manual
7
DCS (Digital Code Squelch), which is used to control
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 to avoid disturbance of unwanted signals.
PT4208 has 83 standard codes (inverted and
non-inverted) for your selection. See table 3.2.
DCS signal is produced by MCU (in waveform of PWM).
It passes through the low pass filter consists of RC to
remove the high frequency components (above 300Hz).
Then the resulting signal is sent 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 to
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.
Table 3.2 DCS Codes
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
3.8 Semiconductor Data
Refer to table 3.3 for descriptions of each pin.
Table 3.3 Definition of CPU Pins
No. Port name Pin Name I/O Function
1 TOPKEY P33 I Top key detect
2 UPKEY P34 I Up key detect
3 MODE I Connect the 4.7K resistor with VCC,
programming test point
4 PTT P43 I [PTT] input
5 DNKEY P44 I Down key detect
6 RST I Reset input, programming test point
7 XOUT O Oscillator
8 VSS I GND
9 XIN I Oscillator（7.3MHz）
10 VCC I 5V CPU power input
11 SHIFT P54 O Clock beat shift. H：On
12 TO0 P53 O (PWM) BPF tuning output
13 TO1 P52 O (PWM) QT/DQT output
14 VDEVC2 P51 I Deviation switch 2 of VHF
15 VDEVC1 P50 I Deviation switch 1 of VHF
16 NC Connect the pull-down resistor with VSS
17 PABC P26 O Final power supply H：On
18 OSCSI P25 I VCO crystal select and connect the
pull-down resistor with VSS. H: 13, L:
16.8
19 WNTC P24 O Wideband/Narrowband control.
H: Wideband L: Narrowband
20 ENC0 P23 I Encoder input
21 ENC2 P22 I Encoder input
22 ENC3 P21 I Encoder input
23 ENC1 P20 I Encoder input
24 PS P17 O PLL power-saving control. H: Normal L:
Power Saving
25 NC Connect the pull-down resistor with VSS
26 NC Connect the pull-down resistor with VSS
27 NC P86 Connect the pull-down resistor with VSS
28 SDA P85 I/O E2PROM data line
29 SCL P84 O E2PROM clock line
30 UL P83 I
I (TRFI)
PLL unlock detect pin
H: Locked L: Unlocked
31 T2IN P82 Reserved：2TONE input
32 DT P81 O PLL data output
33 CK P80 O PLL clock output
34 LE P60 O PLL IC enable pin. H: Locked
35 5MC P45 O Power control except CPU and E2PROM
L：On
36 INT P66 I Power detect input
37 TXD P67 O RS-232C output, programming test point
38 RXD P65 I RS-232C input, programming test point
39 AFCO P64 O AF amplification power
H: On
40 RX P63 O TX/RX VCO select H: Receiving
41 GLED P31 O Green LED control H: On
42 APC P30 O (PWM) TX: Automatic power control output
43 RLED P36 O Red LED control H: On
44 SAVE P32 O
O
Battery saving control. H：Supply power,
L: Power saving
45 MUTE P13 O Mute control. H: MIC mute; L: Audio
mute
46 5RC P12 Receiving power control. L: On
47 5TC O Transmitting power control. H：On
48 NC P10 Speaker mute switch output
49 TI P00 I (A/D8) QT/DQT signal input
50 RSSI I (A/D7) Signal strength detect
51 BUSY P01 I (A/D6) Busy signal input
52 MANDO
WN
P02 I (A/D5) Man-down switch detect
53 BATT P03 I (A/D4) Battery voltage detect
54 NC Connect the pull-down resistor with VSS
55 W588C P62 O Voice alert switch. H: Channel No.
reporting
56 AC P61 O Alarm switch control. H: Controlled by
Volume Switch
The power level must be low in case of
emergency alarm
57 BUSY_V P05 I Voice alert circuit busy detect
58 VCCN P06 O (D/A0) Frequency stability output
59 AVSS I Connect with VSS
60 DTMF P07 O (D/A1) DTMF Output
61 VREF I Connect with VCC
62 AVCC I Connect with VCC
63 DATA_V P37 O Voice alert data

PT4208 Service Manual
8
64 SCLK_V P35 O Voice alert clock
Table 3.4 Function Description of Semiconductor
Components
Position
Mark Model Function Description
IC1 MB15E03 Frequency synthesizer
IC4 NJM2904 APC, voltage comparison, driving
IC5 TA31136 Rx second local oscillator, second IF
amplification, limitation, demodulation, and
noise amplification
IC6 NJM2902 Amplification and filtering of demodulation
signal of receiver.
IC7 NJM2902 MIC amplification, limitation and filtering
IC8 TDA8541 Audio frequency power amplification of
receiver
IC9 AT24C08 E2PROM, memorizes channel frequency data,
function setting parameters and adjusting
status parameters
IC10 R5F212A8 MCU
IC11 PST9140NR MCU reset circuit
IC12 HT7150-1 LDO, low-power voltage regulator
IC15 W588A080 Voice storage IC
Q2 2SC5108 First amplification of transmitter
Q3 2SC3356 Second amplification of transmitter
Q4 2SC5108 VCO buffer amplifier
Q5 2SC5108 VCO buffer amplifier
Q6 2SC4617 VCO power filter
Q7 2SC4738 Noise amplifier
Q9 2SC4617 Audio frequency signal amplification of
receiver
Q10 2SC1623 5V voltage regulation output current stretching
Q11 RD07MVS1 Transmitter final power amplification
Q12 RD01MUS1 Transmitter power amplification driving
Q17 DTA144EE APC output switch
Q19 3SK318 First mixer
Q20 3SK318 Receiver high power amplifier
Q21 KTC4082 1st IF Amplifier
Q22 DTC144EE Red LED Driving
Q23 DTC144EE Green LED Driving
Q24 2SK1824 Voice alert switch
Q26 DTC144EE 5C switch
Q29 KTA1298 5T switch
Q30 KTA1298 5V voltage regulation output current stretching
Q31 KTA1298 5R switch
Q32 KTA1298 5C switch
Q34 DTA144EE Power switch of MIC amplification unit
Q35 2SK1824 Receiver audio output switch. Disconnect on
Emergency
Q36 2SK1824 Receiver audio output switch
Table 3.5 Function Description of Diodes
Position
Mark Model Function Description
D1 MA77 Transmitter antenna switch diode
D2 MA77 Transmitter antenna switch diode
D3 HSC277 VCO output switch
D4 HSC277 Antenna toggle switch
D5 HSC277 Antenna toggle switch
D6 HSC277 VCO output switch
D7 HSC277 5V voltage regulation output current stretching
D8 HVC376B VCO oscillation varactor diode
D9 HVC376B VCO oscillation varactor diode
D12 MA360 VCO modulation diode
D14 HZU5ALL APC output voltage-limiting diode
D15 MA2S111 Unlock detection diode
D16 MA2S111 VCO power filtering acceleration diode
D17 1N4148 Noise demodulation
D18 1N4148 Noise demodulation
D20 Green
LED
Receiving indicator
D25 MA2S111 APC single diode
D28 Red LED Transmitting indicator
D29 Green
LED
Receiving indicator
Table 3.6 Features of Crystal Filter XF1, XF2
Item Rated Value
Nominal center frequency 49.95MHz
Passband width ±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 ---
Table 3.7 Features of CF1 LTVPC450EB
Table 3.8 Schematic Diagram for Packaging of
Semiconductor Devices
3SK318
M: YB-
G1
G2 D
S
G
S
D
CC C
C
B
BB
B
EE
E
E
G
D
S
2SK1824
Mark: B1
2SC5108
M: MC
C
B
E
M: R24
2SC3356
C
B
E
2SC4617
C
B
E
C
B
E
2SC4738 KTC4082
C
B
E
2SC1623
M: L6
KTA1298 DTC144EE
M:16
GND
IN
OUT
HT7150-1
RD01MUS1
D
G
SS
RD07MVS1
RDA0002
1
2
3
DA221
M: K
2SK308NV
DTA144EE
C
B
E
FMMT591
GSD
Item Rated Value
Nominal center frequency 450kHz
6dB bandwidth ±6kHz or higher
50dB bandwidth ±12.5kHz or lower
Pulse 2.0dB or lower
Insertion loss 6.0dB or lower
Guarantee attenuation 35.0db or higher
Terminal impedance 2.0k

PT4208 Service Manual
9
Chapter 4 Mode Introduction
Mode Introduction
Mode Function How to enter
User Mode For normal use Power ON
Data
Programming
Mode
Used to read and write
frequency data and
other features to and
from the radio
Received commands
from PC. See below for
further information.
PC Test Mode Tune the radio
parameters by PC
Received commands
from PC. See below for
further information.
PC
Mode
Firmware
Programming
Mode
Upgrade the radio
when new features are
released
Press and hold the top
key for over 2 seconds
while turning the radio
power ON, and received
commands from PC
Wired Clone Mode
Used to transfer
programming data
from one radio to
another
Press and hold side key 2
for over 2 seconds while
turning the radio power
ON
* User Mode
You can enter User Mode (conventional communication
mode) by turning the radio power ON. Under this mode,
users can use the defined functions of the radio.
* Data Programming Mode
The radio has been set before leaving the factory.
However, due to different requirements of users, the radio’s
operating frequency, channels, CTCSS/DCS, scan, and other
functional parameters should be reprogrammed. Therefore,
Kirisun has specially designed a set of Chinese/English
programming software KSP4208 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
PC are as follows:
A. Install KSP4208 on the computer.
B. Connect the radio to the serial port of the PC with
the special programming cable. Refer to the figure
below.
Figure4.1
C. Turn the computer power ON.
D. Turn the radio power ON.
E. Run the KSP4208 programming software by
double clicking on its executive program.
F. Click “Program” in the main menu of KSP4208,
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
KSP4208 according to requirements of the user:
Radio Information:
Radio Model (model/frequency range), Serial Number,
Embedded Information, MCU Version, Hardware Version,
etc.
Radio Configuration:
(1) Key Assignment: Side Key 1 (Up Key), Side Key 2
(Down Key), and Top Key can be set as long/short key and
the hold time can be defined.
(2) Miscellaneous
1. Wired Clone Mode
2. TOT (Time Out Timer)
3. TOT Reset
4. TOT Pre-alert
5. TOT Re-key time
6. Squelch Level selection
7. Alert Tone
8. Read Data Password
9. Write Data Password
(3) Scan
Scan Function option, Priority Channel, Revert Channel,
Tx Dwell Time, Dropout Delay Time, Lookback Time.
(4) Emergency settings
Channel Parameters
(1) Rx Frequency and Tx Frequency (Step:
2.5KHz/5KHz/6.25KHz)
(2) Rx Signaling and Tx Signaling
a) None
b) CTCSS (60~260Hz @ 0.1Hz step)
c) DCS (-777~777@octal number)
(3) Busy Channel Lockout (BCL)
(4) Beat Shift
(5) Channel Spacing: 25KHz/12.5KHz (Wide/Narrow)
(6) Scan Add/Delete
(7) Tx Power (High/Low)
(8) Clear Tail Tone
(9) CALL1 and CALL2 encode
(10) PTT ID Keyup Telegram, PTT ID Dekey Telegram
DTMF Setting
DTMF Encoder Template
Computer
(RS232 serial port) Programming cable
Radio
(Earphone/Program
ming interface)