Kenwood NX-1200 Series User manual

SERVICE MANUAL
COPYRIGHT © 2019 JVCKENWOOD Corporation No.RA077<Rev.001>
2019/10
B5B-7320-00
VHF TRANSCEIVER, UHF TRANSCEIVER
RA077<Rev.001>201910SERVICE MANUALB5B-7320-00
NX-1200DV, NX-1200D, NX-1200NV, NX-1200N,
NX-1300DU, NX-1300D, NX-1300NU, NX-1300N
COPYRIGHT © 2019 JVCKENWOOD Corporation
NX-1200, NX-1300 series (Basic model)
This product complies with the RoHS directive for the European market. This product uses Lead Free solder.

1-2 (No.RA077<Rev.001>)
TABLE OF CONTENTS
1 PRECAUTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5
2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5
2.1 SYSTEM SET-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5
2.2 REALIGNMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6
2.3 CIRCUIT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-8
2.4 SEMICONDUCTOR DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-12
2.5 COMPONENTS DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-13
2.6 TERMINAL FUNCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-14
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-16
3.1 Precautions for Disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-16
3.2 Precautions for Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-18
3.3 Assembly Information (Sheet/Cushion) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-19
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-20
4.1 NX-1200 Series (K) type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-20
4.2 NX-1300 Series (K4) type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-32
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-45
5.1 Failure diagnosis of the VCO section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-45
5.2 Operating Method of Enforced Firmware Overwriting Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-48
5.3 Replacing TX-RX Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-48
Document Copyrights
Copyright 2019 by JVCKENWOOD Corporation. All rights reserved.
No part of this manual may be reproduced, translated, distributed, or transmitted in any form or by any means, electronic,
mechanical, photocopying, recording, or otherwise, for any purpose without the prior written permission of JVCKENWOOD
Corporation.
Disclaimer
While every precaution has been taken in the preparation of this manual, JVCKENWOOD Corporation assumes no responsibility
for errors or omissions. Neither is any liability assumed for damages resulting from the use of the information contained herein.
JVCKENWOOD Corporation reserves the right to make changes to any products herein at any time for improvement purposes.
Firmware Copyrights
The title to and ownership of copyrights for firmware embedded in KENWOOD product memories are reserved for JVCKENWOOD
Corporation. Any modifying, reverse engineering, copy, reproducing or disclosing on an Internet website of the firmware is strictly
prohibited without prior written consent of JVCKENWOOD Corporation. Furthermore, any reselling, assigning or transferring of the
firmware is also strictly prohibited without embedding the firmware in KENWOOD product memories.
Transceivers containing AMBE+2 Vocoder:
The AMBE+2 voice coding technology is embedded in the firmware under the license of Digital Voice Systems, Inc.
TM
TM

(No.RA077<Rev.001>)1-3
SPECIFICATION
NX-1200 series
Specifications are measured according to applicable standards.
Specifications shown are typical.
JVCKENWOOD Corporation reserves the right to change specifications without prior notice or obligation.
*1 25/30 kHz in VHF/UHF Bands excluding T-Band are not included in the models sold in the USA or US territories.
GENERAL
Frequency Range 136 ~ 174 MHz
Max. Channels per Radio 64 channels
Number of Zones 4 zones
Max. Channels per Zone 16 channels
Channel Spacing Analog 12.5 / 15 / 25*1 / 30*1 kHz
Digital 6.25 / 12.5 kHz
Power Supply 7.5V DC ±20 %
Battery Life
Battery Saver OFF (5-5-90
at High Power)
with KNB-45L Approx. 15 hours (DMR), Approx. 11.5 hours (NXDN / Analog)
with KNB-69L Approx. 19.5 hours (DMR), Approx. 14.5 hours (NXDN / Analog)
with KNB-29N Approx. 11.5 hours (DMR), Approx. 8.5 hours (NXDN / Analog)
with KNB-53N Approx. 10.5 hours (DMR), Approx. 7.5 hours (NXDN / Analog)
Operating Temperature -22°F to +140°F (-30°C to +60°C)
Frequency Stability (-30°C to + 60°C; +25°C Ref.) ±0.5ppm
Antenna Impedance 50 ohm
Dimensions (W x H x D)
(Projections not included)
Radio only 2.13 x 4.84 x 1.32 in (54 x 123 x 33.5 mm)
with KNB-45L 2.13 x 4.84 x 1.32 in (54 x 123 x 33.5 mm)
with KNB-69L 2.13 x 4.84 x 1.48 in (54 x 123 x 37.5 mm)
with KNB-29N/53N 2.13 x 4.84 x 1.32 in (54 x 123 x 33.5 mm)
Weight (net) Radio only 5.6 oz (160 g)
with KNB-45L 9.9 oz (280 g)
with KNB-69L 10.4 oz (295 g)
with KNB-29N/53N 12.3 oz (350 g)
RECEIVER
Sensitivity NXDN @ 6.25 kHz 3 % BER 0.18μV
NXDN @ 12.5 kHz 3 % BER 0.22μV
DMR Digital 1% BER 0.28μV
DMR Digital 5% BER 0.18μV
Analog (12dB SINAD) @ 12.5 / 25 kHz 0.20 / 0.24μV
Selectivity Analog @ 12.5 / 25 kHz 68 / 74 dB
Intermodulation Analog 70 dB
Spurious Rejection Analog 70 dB
Audio Distortion Less than 7 %
Audio Output 1 W / 12 ohm (Internal Speaker)
500 mW / 8 ohm (External Output)
TRANSMITTER
RF Power Output 5 / 4 / 1 W
Spurious Emission -70 dB
FM Hum & Noise Analog @ 12.5 / 25 kHz 40 / 45 dB
Audio Distortion Less than 2 %
Emission Designator 16K0F3E*1, 11K0F3E, 8K30F1E, 8K30F1D, 8K30F7W,
4K00F1E, 4K00F1D, 4K00F7W, 4K00F2D, 7K60FXD,
7K60F7W

1-4 (No.RA077<Rev.001>)
NX-1300 series
Specifications are measured according to applicable standards.
Specifications shown are typical.
JVCKENWOOD Corporation reserves the right to change specifications without prior notice or obligation.
*1 25 kHz in VHF/UHF Bands excluding T-Band are not included in the models sold in the USA or US territories.
GENERAL
Frequency Range 400 ~ 470 MHz
Max. Channels per Radio 64 channels
Number of Zones 4 zones
Max. Channels per Zone 16 channels
Channel Spacing Analog 12.5 / 25*1 kHz
Digital 6.25 / 12.5 kHz
Power Supply 7.5V DC ±20 %
Battery Life
Battery Saver OFF (5-5-90
at High Power)
with KNB-45L Approx. 15 hours (DMR), Approx. 11.5 hours (NXDN / Analog)
with KNB-69L Approx. 19.5 hours (DMR), Approx. 14.5 hours (NXDN / Analog)
with KNB-29N Approx. 11.5 hours (DMR), Approx. 8.5 hours (NXDN / Analog)
with KNB-53N Approx. 10.5 hours (DMR), Approx. 7.5 hours (NXDN / Analog)
Operating Temperature -22°F to +140°F (-30°C to +60°C)
Frequency Stability (-30°C to + 60°C; +25°C Ref.) ±0.5ppm
Antenna Impedance 50 ohm
Dimensions (W x H x D)
(Projections not included)
Radio only 2.13 x 4.84 x 1.32 in (54 x 123 x 33.5 mm)
with KNB-45L 2.13 x 4.84 x 1.32 in (54 x 123 x 33.5 mm)
with KNB-69L 2.13 x 4.84 x 1.48 in (54 x 123 x 37.5 mm)
with KNB-29N/53N 2.13 x 4.84 x 1.32 in (54 x 123 x 33.5 mm)
Weight (net) Radio only 5.6 oz (160 g)
with KNB-45L 9.9 oz (280 g)
with KNB-69L 10.4 oz (295 g)
with KNB-29N/53N 12.3 oz (350 g)
RECEIVER
Sensitivity NXDN @ 6.25 kHz 3 % BER 0.18μV
NXDN @ 12.5 kHz 3 % BER 0.22μV
DMR Digital 1% BER 0.28μV
DMR Digital 5% BER 0.18μV
Analog (12dB SINAD) @ 12.5 / 25 kHz 0.20 / 0.24μV
Selectivity Analog @ 12.5 / 25 kHz 68 / 74 dB
Intermodulation Analog 70 dB
Spurious Rejection Analog 70 dB
Audio Distortion Less than 7 %
Audio Output 1 W / 12 ohm (Internal Speaker)
500 mW / 8 ohm (External Output)
TRANSMITTER
RF Power Output 5 / 4 / 1 W
Spurious Emission -70 dB
FM Hum & Noise Analog @ 12.5 / 25 kHz 40 / 45 dB
Audio Distortion Less than 2 %
Emission Designator 16K0F3E*1, 11K0F3E, 8K30F1E, 8K30F1D, 8K30F7W,
4K00F1E, 4K00F1D, 4K00F7W, 4K00F2D, 7K60FXD,
7K60F7W

(No.RA077<Rev.001>)1-5
SECTION 1
PRECAUTION
This service manual does not describe PRECAUTION.
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
2.1 SYSTEM SET-UP
Merchandise received
Select the type of transceiver
Transceiver programming
A personal computer, programming interface (KPG-22U),
and FPU (programming software) are required for programming.
(The frequency, TX power HI/MID/LOW, and signaling data are
programmed for the transceiver.)
NO
(Option)
(Option)
Delivery
KRA-22 or KRA-26 (for NX-1200)
KRA-23 or KRA-27 (for NX-1300)
Optional antenna
Are you using the optional antenna? YES
Frequency range (MHz) RF power
TX/RX 136~174
TX/RX 136~174
TX/RX 136~174
5W
5W
5W
NX-1200DV K
NX-1200NV K
NX-1200D K
NX-1200N K
NX-1300DU K4
NX-1300NU K4
NX-1300D K4
NX-1300N K4
TX/RX 400~470
TX/RX 136~174
TX/RX 400~470
5W
5W
5W
TX/RX 400~470 5W
TX/RX 400~470 5W
KMC-21, KMC-45D or KMC-48GPS
Speaker microphone
YES
Are you using the speaker microphone?
NO
Type
DMR
NXDN
DMR
NXDN
DMR
NXDN
DMR
NXDN
The KMC-48GPS does not support DMR.

1-6 (No.RA077<Rev.001>)
2.2 REALIGNMENT
2.2.1 Modes
2.2.2 How to Enter Each Mode
2.2.3 PC mode
2.2.3.1 Preface
The transceiver is programmed by using a personal computer
(PC), a USB programming cable (KPG-22U) and a Programming
software (FPU).
The programming software can be used with a PC. Fig.1 shows
the setup of a PC for programming.
Fig.1
2.2.3.2 Connection procedure
(1) Connects the transceiver to the PC using the KPG-22U.
Note:
You must install the KPG-22U driver in the PC to use
the KPG-22U.
(2) When the POWER is switched on, you can immediately
enter user mode.
When PC sends command the transceiver enter PC mode.
When data transmitting from the transceiver, the red LED
lights.
When data receiving to the transceiver, the green LED
lights.
2.2.3.3 KPG-22U description (USB programming interface
cable: Option)
The KPG-22U is a cable which connects to a USB port on a PC.
When using the KPG-22U, install the supplied CD (with driver
software) in the PC.
The KPG-22U driver runs under Windows 7, 8.1, 10.
The latest version of the USB driver is available for download
from the following URL:
https://www.kenwood.com/usb-com/
(This URL may change without notice.)
Mode Function
User mode For normal use.
PC mode Used for communication between the
transceiver and PC.
PC programming
mode
Used to read and write frequency data and
other features to and from the transceiver.
PC test mode Used to check the transceiver using the
PC. This feature is included in the FPU.
PC tuning mode Used to tune the transceiver using the PC.
Clone mode Used to transfer programming data from
one transceiver to another.
Mode Operation
User mode Power ON
PC mode Received commands from PC
Clone mode [Side 2] + Power ON (Two seconds)
User mode
PC programming mode
PC test mode PC tuning mode
PC mode
Clone mode
PC
KPG-22U
FPU
Tuning cable
(W3F-0381-00)
MIC –
MIC +
SP –
SP +

(No.RA077<Rev.001>)1-7
2.2.3.4 Programming software KPG-D6/D6N description
The FPU is the programming software for the transceiver
supplied on a CD.
This software runs under Windows 7, 8.1, 10.
The data can be input to or read from the transceiver and edited
on the screen.
2.2.4 Clone mode
2.2.4.1 Outline
"Clone Mode" copies the transceiver data to another transceiver.
The dealer can copy the transceiver data to another transceiver
even without the use of a PC.
2.2.4.2 Example
The transceiver programming data can be copied from
transceiver to other transceivers through the cloning cable.
2.2.4.3 Operation
The following data cannot be cloned.
• ESN (Electronic Serial Number) data
• Model name
• Tuning data
• Backup data
• Embedded Message with Password
(1) In the source transceiver, press and hold the [Side 2]
button for two seconds while turning the transceiver power
ON and enter the Clone Mode.
The LED of transceiver lights in white.
(2) In the target transceiver, turning the transceiver power ON.
(3) Connecting the cloning cable (part No.E30-3410-05) to the
SP/MIC connectors on the source and target.
(4) Press the [PTT] button on the source while the white LED
of source lights.
The data of the source is sent to the target.
While the target is receiving the data, the green LED of the
target lights.
(5) When cloning of the data is completed, the LED of source
lights for 2 seconds in white and it turns off for 0.5 seconds
alternately. The target automatically operates in the User
mode.
The target can then be operated by the same program as
the source.
If data transmission failed while cloning, yellow and white
LED of target lights alternately.
If the cloning fails, no data will be available in the target
when it is returned to User mode.
(6) The other target can be continuously cloned.
When the [PTT] button on the source is pressed, the the
LED of source lights in white and a beep sounds.
Carry out the operation in step (2) to (5).
Note:
a) If the transceivers Clone Mode is configured as
disabled in the FPU optional features window, the
transceiver cannot enter Clone mode.
b) If the transceiver is in Error Mode, Clone mode
cannot be entered.
c) The conditions and operations when Clone becomes
impossible are as follows.
• The Password (Write) is set to the target
transceiver.
• Between transceivers where the data with different
Model Name, Frequency and Features.
• The Radio Feature setting is enabled on the source
side but the same Radio Feature License setting is
disabled on the target side.
• If the Disable Reading Key Data is enabled through
the FPU.
d) Source transceiver and Target transceiver must have
same model name data if they using the Clone
function.
e) Once transceiver is set to be the Source, it cannot be
a target after all data has been transmitted. This is to
protect the data in the Source transceiver.
Fig.2
2.2.5 Firmware Update
When updating the transceiver firmware, use the updater.
Connect the KPG-22U and execute the updater.
Cloning cable
(E30-3410-05)

1-8 (No.RA077<Rev.001>)
2.3 CIRCUIT DESCRIPTION
2.3.1 Overview
The NX-1200 series is a VHF Analog FM & Digital Portable transceiver designed to operate in the frequency range of 136 to 174MHz.
The unit consists of a transceiver IC, a transmitter, a digital control unit, and a power supply circuit.
The NX-1300 series is a UHF Analog FM & Digital Portable transceiver designed to operate in the frequency range of 400 to 470MHz.
The unit consists of a transceiver IC, a transmitter, a digital control unit, and a power supply circuit.
2.3.2 Frequency Configuration
The receiver uses the direct conversion system. Incoming signals from the antenna are mixed with the local signal from the PLL circuit
and converted to the baseband signal. The transmit signal frequency is generated by the VCO/PLL, and modulated by the signal from
the MPU/DSP. It is then amplified and fed to the antenna.
Fig.1 Frequency configuration
2.3.3 Receiver System
2.3.3.1 RF Circuit
The receive signal from the antenna switch (D101, D102, D103 and D104) passes through the band-pass filter (D200 and D201) to
remove unwanted signals and amplified by a RF amplifier (Q200). The signal passes through another band-pass filter (D202 and
D203) to remove unwanted signals. Then the signal is amplified again by a RF amplifier (incorporated in Transceiver IC (IC200)) and
fed to the mixer (incorporated in Transceiver IC) and converted to the baseband signal.
2.3.3.2 Baseband Circuit
The baseband signal (I/Q signal) pass through amplifiers IC201 & IC202 and is then sent to the MPU/DSP (IC501).
Fig.2 Receiver System
2.3.3.3 Audio Amplifier Circuit
Audio processing (high-pass filter, low-pass filter, de-emphasized and so on) at Analog FM mode and decoding at Digital mode are
processed by MPU/DSP. The Digital signal from MPU/DSP is converted to audio signal at D/A converter (IC604).
The signal goes to internal speaker through the Class-D amplifier (IC302) or Jack connector for external speaker through the single-
end audio power amplifier (IC300).
Fig.3 Audio amplifier circuit
ANT SW RF AMP
ANT
FINAL AMP
DRIVE AMP
TRANSCEIVER IC
VCO
PLL TCXO
MPU/DSP
AF AMP
MIC AMP
SP
MIC
ANT
ANT SW
RF AMP
HPF
VCO
OP AMP
(I/Q) MPU/DSP
IC200
BPF
BPF
MIXER IC501
D101
D102
D103
D104
D200
D201
Q200 D202
D203
TRANSCEIVER IC
IC201
IC202
RF AMP
Q4
TRANSCEIVER IC MPU/DSP D/A Converter
AUDIO AMP
OP AMP
(I/Q)
IC200
IC201
IC202 IC501 IC604
IC302
IC300
Internal Speaker
External Speaker
AUDIO AMP

(No.RA077<Rev.001>)1-9
2.3.4 Transmitter System
2.3.4.1 Audio Band Circuit
The signal from microphone is amplified through a microphone amplifier IC602 (including AGC function) and input into MPU/DSP
(IC501) for audio processing. Voice signals of 300Hz or lower and frequencies of 3kHz or higher are cut off and an audio range 300Hz
to 3kHz is extracted. The audio signal is then pre-emphasized in FM mode and synthesized with the signals, such as QT and DQT,
as required, and is transferred to PLL (IC2). The DTMF and MSK baseband signals are also generated by IC501.
In Digital mode, the audio signal is converted to the 4-Level FSK baseband signal and is transferred to VCO circuit.
2.3.4.2 Drive and Final amplifier
The signal from the Transceiver IC (IC200) is amplified by pre-drive amplifier (Q104). The output of the pre-drive amplifier is amplified
by the drive amplifier (Q106) and final amplifier (Q107) to 5W (4W when the power is medium and 1W when the power is low). Q106
and Q107 are MOS FET. The output of the final amplifier is then passed through the harmonic filter (LPF) and antenna switch (D101
and D102) and applied to the antenna terminal.
Fig.4 Transmitter System
2.3.5 PLL Frequency Synthesizer
2.3.5.1 TCXO (X1)
TCXO (X1) generates a reference frequency of 16.8MHz for the PLL frequency synthesizer.
The oscillation frequency is adjusted TCXO directly by controlled the D/A converter (IC604).
2.3.5.2 VCO
•NX-1200 series
There is one VCO contain TX VCO and RX VCO.
The VCO (Q4) generates the carrier for the transmitter and the receiver. The VCO oscillation frequency range is 272 to 348MHz.
The transmit frequency range is same as receiver frequency range.
The local signal frequency range is also 272 to 348MHz.
The oscillation frequency is divided into two by IC200 and it becomes the operating frequency.
The VCO oscillation frequency is determined by voltage control terminals "CP" and "ASSIST".
The voltage control terminal "CP" is controlled by PLL (IC2). The voltage control terminal "ASSIST" is controlled by the control
voltage from D/A converter (IC604).
For the modulation input terminal, "MOD", the output frequency changes according to the applied voltage. This is used to modulate
the VCO output.
•NX-1300 series
There is one VCO contain TX VCO and RX VCO.
The VCO (Q4) generates the carrier for the transmitter and the receiver. The VCO oscillation frequency range is 800 to 940MHz.
The transmit frequency range is same as receiver frequency range.
The local signal frequency range is also 800 to 940MHz.
The oscillation frequency is divided into two by IC200 and it becomes the operating frequency.
The VCO oscillation frequency is determined by voltage control terminals "CP" and "ASSIST".
The voltage control terminal "CP" is controlled by PLL (IC2). The voltage control terminal "ASSIST" is controlled by the control
voltage from D/A converter (IC604).
For the modulation input terminal, "MOD", the output frequency changes according to the applied voltage. This is used to modulate
the VCO output.
ANT SW
FINAL AMP
DRIVE AMP
TRANSCEIVER IC
VCO
PLL TCXO
MPU/DSP
MIC AMP
MIC
IC501
IC602
D101
D102
IC200
Q106Q107
PRE DRIVE
AMP
Q104
IC2 X1
16.8MHz
Q4
ANT

1-10 (No.RA077<Rev.001>)
2.3.5.3 PLL
PLL (IC2) compares the difference in phases of the VCO oscillation signal and the TCXO (X1) reference frequency. And it returns the
difference voltage to the VCO CP terminal and realizes the "Phase Locked Loop". This allows the VCO oscillation frequency to
accurately match (lock) the desired frequency.
When the frequency is controlled by the PLL, the frequency convergence time increases as the frequency difference increases when
the set frequency is changed. To supplement this, The ASSIST Voltage from D/A converter (IC604) is used before control by the PLL
(IC2) to bring the VCO oscillation frequency close to the desired frequency. As a result, the VCO CP voltage does not change and is
always stable at approx. 2.5V.
The desired frequency is set for the PLL (IC2) by the MPU/DSP (IC501) through the 3-line "PLL_LE", "PLL_DATA", "PLL_CLK" serial
bus for PLL. IC501 monitors through the "PLL_LD", whether the PLL (IC2) is locked or not. If the VCO does not lock to desired
frequency (unlock), the "PLL_LD" logic is low.
2.3.6 Control Circuit
The control circuit consists of MPU/DSP (IC501) and its peripheral circuits. IC501 mainly performs the following;
(1) Switching between transmission and reception by PTT signal input.
(2) Reading system, zone, frequency, and program data from the memory circuit.
(3) Sending frequency program data to the PLL.
(4) Controlling the audio mute circuit by decode data input.
2.3.6.1 MPU/DSP
This MPU/DSP (IC501) operates at 168MHz (MAX) clock and 3.2V DC. Controls the flash memory, the receive circuit, the transmitter
circuit, the control circuit, and the display circuit.
2.3.6.2 Memory Circuit
Memory circuit consists of the MPU/DSP (IC501) and the flash memory (IC500). The flash memory has capacity of 16Mbit that
contains the transceiver control program for the MPU/DSP and stores the data. It also stores the data for transceiver channels and
operating parameter that are written by the FPU. This program can be easily written from external devices.
Flash memory
Note:
The flash memory (IC500) stores the data that is written by the FPU (KPG-D6/D6N), tuning data (Deviation, Squelch, etc.), and other
data (User mode, Test mode, Tuning mode, ESN, etc). If changing the flash memory, please contact our service center.
2.3.6.3 Low Battery Warning
The battery voltage is divided using R110 and R111, it is detected by A/D converter (incorporated in MPU/DSP (IC501)). When the
battery voltage falls below the voltage set by the Low battery warning adjustment, the red LED blinks to notify the operator that it is
time to replace the battery. If the battery voltage falls even more (approx. 5.8V), a beep sounds and transmission stops.
2.3.6.4 DSP
The DSP circuit consists of a MPU/DSP (IC501) and processes the base band signal. The MPU/DSP operates at 168MHz (MAX)
clock, the I/O section operates at 3.2V.
The DSP carries out the following processes:
• 4-Level FSK processing
• Analog FM pre-emphasis/de-emphasis
• Vocoder processing between audio and modulation/demodulation
• CAI processing, such as error correction encoding
• QT/DQT encoding/decoding
• DTMF encoding/decoding
• MSK encoding/decoding
• 2-tone encoding/decoding
• Compressor/expander processing
• Voice scrambler processing
• Transmit/receive audio filtering processing
• Audio mute processing
• Modulation level processing
• Active Noise Reduction
• Voice announce processing
Low battery warning Battery condition
The red LED blinks during transmission. The battery voltage is low but the transceiver is still usable.
The red LED blinks and the warning tone beeps while the
PTT is pressed.
The battery voltage is low and the transceiver is not usable to make calls.

(No.RA077<Rev.001>)1-11
2.3.7 Power Supply Circuit
The battery voltage (+B) is provided from battery terminal. The battery voltage passes through the 3.15A fuse (F400), and goes to
RF Drive and final amplifier, DC/DC converter (IC407), AF amplifier (IC300 through the 1.0A fuse (F300)), and INT DET IC (IC406).
IC406 monitors battery voltage. If the battery voltage is enough higher than 5.6V, IC406 outputs "High".
When the Power SW is turned on, SB becomes "High" (battery voltage). DC/DC (IC408) operates if both SB and IC406 output are
"High". IC407 (38M) outputs 3.8V, and IC404 (32M) outputs 3.2V. IC408 (32MD) outputs 3.2V. IC203 (32B) outputs 3.2V. Reset IC
(IC405) watches IC408 (32MD) output voltage. If the 32MD output voltage is enough higher than 2.8V, Reset IC (IC405) outputs
"High". As a result, MPU/DSP (IC501) operates.
SBC signal becomes "High" after MPU/DSP (IC501) operates, and IC400 (50M), IC401 (50C), IC403 (32C), and IC1 (32MS) are
turned on.
When 50VC signal becomes "High", IC402 (50V) operates. When 5TC signal becomes "High", Q400 (50T) is turned on. Q400 (50T)
is turned on in transmit mode. Switches are controlled by MPU/DSP (IC501).
When the Power SW is turned off, /SB_DET signal becomes "High". After detecting /SB_DET signal, MPU/DSP (IC501) changes SBC
signal to "Low".
38M is fed to IC3 (200C). IC3 (200C) is the DC/DC boost converter. IC3, D1, C34 consist of a voltage quadrupler.
The 200C circuit then outputs approximately +20VDC.
Fig.5 Power Supply Circuit
2.3.8 Signaling Circuit
2.3.8.1 Encode (QT/DQT/DTMF/2-tone/MSK)
Each signaling data signal of QT, DQT, DTMF, 2-tone and MSK is generated by the MPU/DSP (IC501), superposed on a modulation
signal and output to VCO and PLL.
2.3.8.2 Decode (QT/DQT/DTMF/2-tone/MSK)
The audio signal and signaling data (QT, DQT, DTMF, 2-tone and MSK) are separated by the MPU/DSP (IC501). Next the MPU/DSP
(IC501) decode the signaling data.
F400
+B
BATT
GND IC400 50M
SBC
Q400 50T
5TC
IC402
50VC
50V
IC401
32CC
50C
IC406 INT
IC407
DC/DC
IC404 32M
SBC/PWR
SBC/PWR
IC408
DC/DC
SBC/PWR
32MD
IC405
RESET RESET
IC1
32MSC
32MS
IC203 32B
IC403
32CC
32C
200C
IC501
5TC
32CC
50VC
SBC
32MC
Power SW
D401 INT
SBC/PWR
DC SW
AVR
AVR
AVR
INT DET
AVR
AVR
AVR
AVR
MPU/DSP
IC3
DC/DC
D402
DC SW
SB
38M
/SB_DET

1-12 (No.RA077<Rev.001>)
2.4 SEMICONDUCTOR DATA
2.4.1 MPU/DSP: 2F405VGT6KHGA (TX-RX unit IC501)
Pin No. Name I/O Function
1 BSHIFT O MPU/DSP Clock frequency Shift
2 NC - No Connection
3 NC - No Connection
4 NC - No Connection
5 NC - No Connection
6 VBAT -
7 /PF2 I Programmable Function Key Input 2
8 /PF1 I Programmable Function Key Input 1
9 EN4 I Encoder Input 4
10 VSS - GND
11 VDD - 32MD
12 XIN I Crystal (19.2MHz)
13 NC - No Connection
14 RESET I RESET
15 VOX I VOX detection
16 CURR I Current detection
17 BATT I Encoder Input 2
18 CVIN I VCO Lock Voltage IN
19 VDD - 32MD
20 VSSA - GND
21 VREF+ - 32M
22 VDDA - 32M
23 TH_DET2 I Thermistor DET
(Temperature detection for RX)
24 VOL I VOL IN
25 TH_DET1 I Thermistor DET
(Temperature detection for TX)
26 MICI I MIC input
27 VSS - GND
28 VDD - 32MD
29 AUDIOO O AUDIO output
30 MOD O MOD output
31 APCSW O APC Switch
32 EN1 I Encoder Input 1
33 EN3 I Encoder Input 3
34 RXI I I signal from IC200
35 RXQ I Q signal from IC200
36 NC - No Connection
37 EN2 I Encoder Input 2
38 NC - No Connection
39 EXTSPSW O Speaker Mute
40 3RC O LNA DC switch
41 1PINDET I 1 pin detect for external speaker
42 BLULED O Blue LED
43 /INSPMT O Internal Speaker Mute
44 50VC O 5V AVR Control for GPS MIC
45 NC - No Connection
46 DSW O APC Voltage Discharge Switch
47 DAC2_CLK O CLK for DAC IC605
48 DAC2_DATA O DATA for DAC IC605
49 VCAP_1 - 2.2uF
50 VDD - 32MD
51 CMX_CSN O CSN for IC200
52 CMX_SCLK O CLK for IC200
53 CMX_RDATA I DATA from IC200
54 CMX_CDATA O DATA to IC200
55 TEST_TX O UART_TX for Test
56 TEST_RX I UART_TX for Test
57 SIM2 I
58 EMPTT O Emergency PTT
59 PTT I PTT button
60 GRNLED O Green LED Control
61 OPTDET I Option Detection
62 REDLED O Red LED Control
63 INSPSW O Internal Speaker Switch
64 DAC_DI O Ext DAC Data
65 DAC_CLK O Ext DAC Clock (↑ edge data input)
66 DAC_LD O Ext DAC LD(↑ edge data active)
67 TX/RX O TX RX Switch
68 TXD O Serial Data to MIC JACK
69 RXD I Serial Data from MIC JACK
70 PLL_LD I Unlock for PLL
71 ASTSW O Assist Switch
72 SWDIO I/O SWDIO for SWD
73 VCAP_2 - 2.2uF
74 VSS3 - GND
75 VDD5 - 32MD
76 SWCLK I/O SWCLK for SWD
77 /F_CS O Chip Select for Flash memory
78 F_SCLK O Clock for Flash memory
79 F_DATAI I DATA Input for Flash memory
80 F_DATAO O DATA Output to Flash memory
81 /F_WP O Write protect for Flash memory
82 3MSC O 32MS Switch Control
83 NC - No Connection
84 NC - No Connection
85 NC - No Connection
86 PLL_DATA O Data Output for PLL
87 PLL_LE O Chip Select for PLL
88 PLL_CLK O Clock for PLL
89 SWO O SWO for SWD
Pin No. Name I/O Function

(No.RA077<Rev.001>)1-13
2.5 COMPONENTS DESCRIPTION
2.5.1 TX-RX Unit (XC1-295K-01, XC1-296K-01)
90 SRST I SRST for SWD
91 SBC O SB switch control
92 FLDM I Force Flash Load Mode
93 /SB_DET I Power Switch detect
94 BOOT0 -
95 SIM1 I
96 3CC O 5C and 32C Control
97 /INT I Interrupt
98 5TC O 5T Control
99 PDR_ON - GND
100 VDD6 - 32MD
Ref. No. Part Name Use / Function
IC1 IC Voltage regulator (32MS)
[3.2V AVR]
IC2 IC PLL IC
IC3 IC DC-DC Converter (200C)
[20V DC-DC]
IC4,5 IC DC amplifier [DC AMP]
IC6 IC Buffer amplifier [BUFF AMP]
* Q6 is only used in XC1-295K-01.
IC100 IC DC amplifier [DC AMP]
IC200 IC Transceiver IC
IC201,202 IC IQ AMP
IC203 IC Voltage regulator (32B) [3.2V AVR]
IC300 IC AF AMP
IC301 IC Buffer amplifier [BUFF AMP]
IC302 IC AF AMP
IC400 IC Voltage regulator (50M) [5.0V AVR]
IC401 IC Voltage regulator (50C) [5.0V AVR]
IC402 IC Voltage regulator (50V) [5.0V AVR]
IC403 IC Voltage regulator (32C) [3.2V AVR]
IC404 IC Voltage regulator (32M) [3.2V AVR]
IC405 IC Reset
IC406 IC INT DET
IC407 IC DC-DC converter (38M)
[3.8V DC-DC]
IC408 IC Voltage regulator (32MD)
[3.2V AVR]
IC500 IC Flash memory [FLASH]
IC501 IC MPU/DSP
IC502 IC Clock Buffer amplifier
[CLK BUFF AMP]
IC600 IC APC buffer [APC BUFF]
IC601 IC Modulation amplifier [MOD AMP]
Pin No. Name I/O Function
IC602 IC MIC AMP
IC603 IC AF AMP Filter [AF AMP FIL]
IC604,605 IC D/A converter [DAC]
IC606 IC VOX AMP
Q1 FET DC switch (assist) [DC SW]
Q3 TRANSISTOR Ripple filter
Q4 FET VCO
Q5,6 TRANSISTOR VCO buffer [VCO BUFF]
* Q6 is only used in XC1-295K-01.
Q100 TRANSISTOR Buffer amplifier [BUFF AMP]
Q101 FET DC switch (Batt DET) [DC SW]
Q102 FET DC switch (Curr DET) [DC SW]
Q103 TRANSISTOR DC switch [DC SW]
Q104 FET Pre-drive [PRE-DRV]
Q105 FET DC switch (APC) [DC SW]
Q106 FET Drive amplifier [DRV AMP]
Q107 FET RF final amplifier [FINAL]
Q108 FET DC switch (APC) [DC SW]
Q200 TRANSISTOR RF amplifier [RF AMP]
Q202 FET DC switch (32R) [DC SW]
Q300 TRANSISTOR DC switch (RED LED) [DC SW]
Q301 TRANSISTOR DC switch (GREEN LED) [DC SW]
Q302 TRANSISTOR DC switch (BLUE LED) [DC SW]
Q303,304 FET DC switch [DC SW]
Q305 TRANSISTOR DC switch [DC SW]
Q306,307 TRANSISTOR DC switch (Audio amplifier)
[DC SW]
Q308 FET Level shifter
Q309,310 TRANSISTOR DC Stabler [DC SW]
Q311 TRANSISTOR DC switch (Audio amplifier)
[DC SW]
Q312 TRANSISTOR DC switch (Emergency PTT)
[DC SW]
Q313 FET Level shifter
Q400 FET DC switch (5T Control) [DC SW]
Q402 FET DC switch [DC SW]
Q403 TRANSISTOR DC switch (Batt DET) [DC SW]
Q404 FET DC switch (Interrupt) [DC SW]
Q600,601 TRANSISTOR MIC AGC
D1 DIODE DC-DC converter [DC-DC CONV]
D2 ZENER
DIODE
Voltage regulator Protection
D4 DIODE Ripple filter
D5-10
VARIABLE
CAPACITANCE
DIODE
VCO Frequency control [VCO]
D101-104 DIODE Antenna switch [ANT SW]
D105 VARISTOR Surge protection [SURGE P]
Ref. No. Part Name Use / Function

1-14 (No.RA077<Rev.001>)
2.6 TERMINAL FUNCTION
2.6.1 TX-RX unit (XC1-295K-01, XC1-296K-01)
D200-203 VARIABLE
CAPACITANCE
DIODE
RF BPF control [RF BPF CTL]
D300 DIODE LED indicator [IND]
D303 DIODE DC switch [DC SW]
D304-307 VARISTOR Surge protection [SURGE P]
D400 DIODE Reverse current protection
D401 DIODE DC switch [DC SW]
D402 DIODE 38M control [38 CTL]
D600, 601 DIODE MIC AGC
D602 DIODE VOX
D603 DIODE VOX
Pin
No.
Name I/O Function
CN300
1 VOL I Volume level input
2GND-GND
3 SB I Switched B input
4 SB I Switched B input
5 +B O Power output after passing through the fuse
6 +B O Power output after passing through the fuse
7 32M O DC 3.2V output
8 EN2 I Selector input
9 EN4 I Selector input
10 GND - GND
11 EN3 I Selector input
12 EN1 I Selector input
Ref. No. Part Name Use / Function

(No.RA077<Rev.001>)1-15
2.6.2 SP/MIC Connector Specification
Pin
No.
Pin
Name
I/O Signal
Type
Description Item and Condition Min Typ Max Unit Note
1 PTT/RXD I Digital PTT/RXD input
Zin = 47kohm
Internal Pull-up (5V)
Input Voltage (High) 4 5 6 V
Input Voltage (Low) 0 0.5 V
Baud Rate 0.2304 Mbps
2 MICI I Analog External MIC input
Zin = 1.8kohm@1kHz
Bias = 5.0V (Load=Open)
Frequency range = 0.3~3kHz
Before Pre-emphasis
Maximum Input
Voltage
1100 mVrms
Standard Input
Voltage
9.2 15 20.8 mVrms AF = 1kHz
60% of system Dev
MIC sens = Normal
3 MICO O Analog Internal MIC output <Unable to connect>
4 OPTDET I Digital External option detection
Zin = 74kohm
Internal Pull-down (0V)
Active Low
<Unable to connect>
5 50V O Power DC 5V output
(Controlled by MPU/DSP)
Output Voltage 4.9 5 5.1 V Io = 30mA
Maximum Output
Current
100 mA
6 AE - GND GND Maximum Input
Current
700 mA
7 TXD O Digital TXD output
Zout = 6.8kohm
Internal Pull-up (5V)
Output Voltage (High) 4.9 5 5.1 V Load = Open
Output Voltage (Low) 0 0.1 V Load = Open
Baud Rate 0.2304 Mbps
8 NC - - No Connection <Unable to connect>
9 DET I Digital External Speaker Detection
Zin = 47kohm
Internal Pull-up (5V)
<Unable to connect>
10 SPO O Analog Internal Audio output
Frequency range = 0.3~3kHz
After De-emphasis
Maximum Output
Power
1300 mW AF = 0.3~3kHz
FM Dev.= Maximum
Load = 8ohm
P.S. = 9.0V
Standard Output
Power
400 500 mW AF = 1kHz
Load = 8ohm
THD = 10%
P.S. = 7.5V

1-16 (No.RA077<Rev.001>)
SECTION 3
DISASSEMBLY
3.1 Precautions for Disassembly
3.1.1 Removing the TX-RX unit and other parts.
(1) Loosen CAP screw and remove the CAP.<1>
(2) Remove Volume Knob & Selector Knob.<2>
(3) Remove the two screws tightened on Chassis. <3>
(4) Lift the bottom of the chassis and remove it from the front
case.
(5) Remove Rubber Seal of phone jack and Rubber Seal at top
side.
(6) Remove Speaker Holder Assy from Chassis.
Press on the hooking portion of Speaker Holder and
remove the Speaker Holder Assy from Chassis.
Note:
Please be cautious the wires are still connected to
Speaker and MIC element.
Desolder to remove the Holder Assy.
Speaker Wires x2
MIC Wires x2
<1>
<2>
<3>
<2>
<3>
Holder Assy is fixed by this hook.
Press
SP+
SP-
MIC+
MIC-
32M
5T 5M
RXD
M+
MICO
SPO
S-
M-
S+
SP+
SP-
MIC+
MIC-
Holder Assy

(No.RA077<Rev.001>)1-17
(7) Remove PCB screws (x8).
(8) Desolder the ANT Receptacle and Positive Terminal.
(9) Unlock the FPC connector and remove FPC cable from it,
then remove the PCB from Chassis.
(10) Untighten the screws of ANT Receptacle and circular nuts
of Variable Resistor (Volume) & Rotary Switch (Selector),
then remove ANT Receptacle, spring washers, Volume,
Selector from Chassis.
(11) Remove Rubber Seal & Holder Assy, Packing from
Chassis.
(12) Remove the Battery Release Lever from the front case.
• Press the upper part of the lever toward the inside of the
front case. One side of the shaft will be removed. <1>
• Lift and remove the battery release lever from the front
case. <2>
Note:
Scratch and widen the glue hole if there is difficulty in
removing the other end of the shaft.
No glue is required when you reassemble the battery
release lever.
Desolder
ANT Receptacle
Desolder
Positive terminal
Latch
Lift the latch to unlock the FPC connector.
FPC connector
Spring Washer
Circular Nut
Volume
Selector
ANT
Receptacle
Packing
Rubber Seal
Holder
A
ssy
<1>
<2>
Battery Release Lever

1-18 (No.RA077<Rev.001>)
3.2 Precautions for Reassembly
(1) Attach Rubber Sheet & Cushion to the chassis.
(2) Attach Terminal (-) with Cushion to the chassis.
(3) Attach the Knob and other parts to the Volume/ Selector as
shown.
Note:
Jig for Circular Nut (Part No.: W05-1012-00)
(4) Attaching the Battery Release Lever to the Front Case
• Insert one side of the shaft into the hole at the lever fitting
section on the Front Case.<1>
Note:
The thin spring should be positioned above the two
tabs of the lever.
• Tilt the battery release lever slightly forward <2>, so that
the thick spring is positioned below the case surface.
• With the thick spring positioned below the Front Case
surface, attach the other side of the shaft to the Front
Case by pressing the battery release lever <3> until it
snaps into place <4>.
Note:
Be careful not to tilt the battery release lever too
forward.
If the battery release lever is pushed in this state
where the two tabs come below the Front Case
surface, there is a possibility of damaging the two
tabs.
Battery Release Lever is completely fixed when the
chassis is assembled to the Front Case.
Cushion
Cushion
Rubber Sheet
Terminal (-)
Cushion
Circular Nut
Knob
Volume
Selector
Washer
Rubber Seal
<1>
<2>
A thin spring
Shaft
Tow tabs
A thick spring
<3>
<4>

(No.RA077<Rev.001>)1-19
(5) Assembling the Battery Release Lever
• Place the lever <2> onto the stopper <1>.
• Place the thick spring <3> onto the lever.
• Hook the right and left ends of the thin spring <4> onto
the tabs of the stopper, then place the thin spring onto
the lever <5>.
• Slide the shaft through the hole of the stopper and lever
<6>.
(6) Attaching the Positive Terminal to the Chassis
Always attach the positive terminal to the chassis, using
the following procedures, before attaching the TX-RX unit
onto the chassis.
• Attach the Packing to the chassis.
Attach the Holder Assy to the Packing.
3.3 Assembly Information (Sheet/Cushion)
When "Main Parts" is changed (ordered), "Assembled Sheet / Cushion" should also be changed (ordered) together.
The Sticker and Sheet etc are non-reusable parts. It requires the new one to get the radio’s performance after repairs.
<3>
<4>
<2>
<6>
<1>
<5>
Packing
Holder Assy
Main Parts Assembled Sheet/ Cushion
Part Number Part Name Part Number Part Name
A1A-0131-02 CHASSIS G13-2009-04 CUSHION
G13-2034-24 CUSHION
K2K-0411-00 BUTTON KNOB J9K-0054-00 ADHESIVE SHEET

1-20 (No.RA077<Rev.001>)
SECTION 4
ADJUSTMENT
4.1 NX-1200 Series (K) type
4.1.1 Test Equipment Required for Alignment
*The test equipment which is not used for adjustment is contained in this table.
Antenna connector adapter
The antenna connector of this transceiver uses an SMA terminal.
Use an antenna connector adapter [SMA(f) - BNC(f) or SMA(f) -
N(f)] for adjustment. (The adapter is not provided as an option,
so buy a commercially-available one.)
Battery Jig (W05-1011-00)
Connect the power cable properly between the battery jig
installed in the transceiver and the power supply, and be sure
output voltage and the power supply polarity prior to switching
the power supply ON, otherwise over voltage and reverse
connection may damage the transceiver, or the power supply or
both.
Note:
When using the battery jig, you must measure the voltage at
the terminals of the battery jig. Otherwise, a slight voltage
drop may occur within the power cable, between the power
supply and the battery jig, especially while the transceiver
transmits.
Test Equipment Major Specifications
1. Standard Signal
Generator (SSG)
Frequency Range 100 to 520MHz
Modulation Frequency modulation and external modulation
Output -127dBm/0.1μV to greater than -47dBm/1mV
2. Power Meter Input Impedance 50ohm
Operation Frequency 100 to 520MHz
Measuring Range Vicinity of 10W
3. Deviation Meter Frequency Range 100 to 520MHz
4. Digital Volt Meter
(DVM)
Measuring Range 10mV to 10V DC
Input Impedance High input impedance for minimum circuit loading
5. Oscilloscope DC through 30MHz
6. Frequency Counter Frequency Range 10Hz to 1000MHz
Frequency Stability 0.2ppm or less
7. Ammeter 5A
8. AF Volt Meter (AF VM) Frequency Range 50Hz to 10kHz
Voltage Range 1mV to 10V
9. Audio Generator (AG) Frequency Range 50Hz to 5kHz or more
Output 0 to 1V
10. Distortion Meter Capability 3% or less at 1kHz
Input Level 50mV to 10Vrms
11. 8ohm Dummy Load Approx. 8ohm 3W
12. Regulated Power Supply 5V to 10V, approx. 3A
Useful if ammeter equipped
- Terminal (Black)
+ Terminal (Red)
–
+
C1
100P/25V
C2
470P/25V
C3
100μ/25V
+
(Red)
+Terminal
–Terminal
(Black)
supply
Power
Power
cable
Schematic diagram