Standard Horizon HX280S, HX280E Service Manual
VHF FM Marine Transceiver
HX280S/E
SERVICE MANUAL
HX280S HX280E
EM038N90A
1
Specifications (HX280S)
General
Frequency Ranges: TX: 156.025 MHz - 157.425 MHz
RX: 156.050 MHz - 163.275 MHz
Channel Spacing: 25 kHz
Frequency Stability: ±5 ppm (–4 °F to +140 °F [–20 °C to +60 °C])
Emission Type: 16K0G3E
Antenna Impedance: 50 Ω
Supply Voltage: 7.4V DC, Negative Ground (Battery Terminal)
Current Consumption: 320 mA (Receive, Typical at AF MAX.)
50 mA (Standby)
1.6 A / 0.7 A (TX: 5 W / 1W)
Operating Temperature: –4 °F to +140 °F (–20 °C to +60 °C)
Case Size (W x H x D): 2.20” x 5.24” x 1.08” (56 x 133 x 27.5 mm) w/o knob & antenna
Weight (Approx.): 10.9 oz (310 g) w/FNB-V105LI, Belt Clip, & Antenna
Transmitter
RF Power Output: 5 W / 1 W (@7.4 V )
Modulation Type: Variable Reactance
Maximum Deviation: ±5 kHz
Spurious Emission: –75 dBc typical
Microphone Impedance:2 kΩ
Receiver
Circuit Type: Double-Conversion Superheterodyne
Intermediate Frequencies: 1st: 21.7 MHz, 2nd: 450 kHz
Adjacent Channel Selectivity: 70 dB typical
Intermodulation: 68 dB typical
Hum & Noise Ratio: 40 dB typical
Sensitivity: 0.25 μV for 12 dB SINAD
Selectivity: 25 kHz (–70 dB)
AF Output (Internal SP): 700 mW @16 Ω for 10 % THD (@7.4 V)
Performance specifications are nominal, unless otherwise indicated, and are subject to change without notice.
Measured in accordance with TIA/EIA-603.
Important Note
The HX280S and HX280E was assembled using Pb (lead) free solder, based on the RoHS specification. Only lead-free solder (Alloy Composition: Sn-3.0Ag-0.5Cu) should be used for repairs performed on this apparatus. The solder stated above utilizes the alloy composition required for compliance with the lead-free specification, and any solder with the above alloy composition may be used.
2
Specifications (HX280E)
General
Frequency Ranges: 156.025 MHz - 162.000 MHz
Channel Spacing: 25 kHz
Frequency Stability: ±5 ppm (–20 °C to +60 °C)
Emission Type: 16K0G3E
Antenna Impedance: 50 Ω
Supply Voltage: 7.4V DC, Negative Ground (Battery Terminal)
Current Consumption: 320 mA (Receive, Typical at AF MAX.)
50 mA (Standby)
1.6 A / 0.7 A (TX: 5 W / 1W)
Operating Temperature: –20 °C to +60 °C
Case Size (W x H x D): 56 x 133 x 27.5 mm (w/o knob & antenna)
Weight (Approx.): 310 g (w/FNB-V105LI, Belt Clip, & Antenna)
Transmitter
RF Power Output: 5 W / 1 W (@7.4 V )
Modulation Type: Variable Reactance
Maximum Deviation: ±5 kHz
Spurious Emission: Less than 0.25 μW
Microphone Impedance:2 kΩ
Receiver
Circuit Type: Double-Conversion Superheterodyne
Intermediate Frequencies: 1st: 21.7 MHz, 2nd: 450 kHz
Adjacent Channel Selectivity: 70 dB
Intermodulation: 68 dB
Hum & Noise Ratio: 40 dB
Sensitivity:1 μV for 20 dB SINAD
Selectivity: 25 kHz (–70 dB)
AF Output (Internal SP): 700 mW @16 Ω for 10 % THD (@7.4 V)
Performance specifications are nominal, unless otherwise indicated, and are subject to change without notice.
Measured in accordance with EN301 178-2, EN300 698-3, EN301 843-2, EN60950-1
3
Exploded View & Miscellaneous Parts
CP9402001 (HX280S: USA)
CP9402002 (HX280S: EXP)
CP9402003 (HX280E: EU)
CP9402004 (HX280E: UK)
FRONT PANEL ASSY
RA0905300
COIL SPRING (C065)
RA1079100
LATCH NAIL
RA1078700
KNOB (VOL)
SPONGE RUBBER (WINDOW)
G6090189
RA1078900
LIGHT GUID (LCD)
RA1081000
INTER CONNECTOR (LCD)
RA1089600
REFLECTOR SHEET
Unsolder the three battery terminals
to remove the MAIN Unit
from the Rear Case
RA1079400
RING NUT (VOL)
RA1089500
LCD
e
e
e
e
e
e
e
e
e
RA1079200
LATCH PLATE
RA1078800
HOLDER (PTT)
RA1079600
RUBBER KNOB (PTT)
RA1080100 (HX280S)
RA1101200 (HX280E)
RUBBER KNOB
e
e
MAIN UNIT
VXSTD P/N
Q3000176
AAG43X001
Q9500142
Q9500143
Q9500144
CB4777001
4
RUBBER PACKING (VOL)
RA1079500
CS2020101
TERMINAL ASSY
RA1089600
RUBBER PACKING (TERMINAL)
RA1078500
CASE COVER (REAR)
RA091970
O RING (6x2.2)
DESCRIPTION
CAT460 Antenna
FNB-V105LI Li-Ion Battery Pack
NC-90B 120VAC Wall Charger (Type-A plug)
NC-90C 230VAC Wall Charger (Type-C plug)
NC-90U 230VAC Wall Charger (Type-BF plug)
CD-46 Charger Cradle
c
e
e
REF.
c
d
e
d
VXSTD P/N
U02310020
U24106020
U9900068
RA1079800
RUBBER PACKING (CASE)
CP9401001
REAR PANEL ASSY
d
CP9403001
BELT CLIP ASSY
Non-designated parts are available only
as part of a designated assembly.
DESCRIPTION
SEMS SCREW SM3X10SUS
BIND HEAD TAPTITE-B M2X6SUS
PAN HEAD TAPTITE-B M2X4NI#3
QTY.
1
2
13
Block Diagram
5
Note
6
Circuit Description
1. Receive Signal Path
Incoming RF from the antenna jack passes through a lowpass filter consisting of coils L1001, L1002, & L1004, capacitors C1005, C1014, C1015, & C1019, and antenna
switching diode D1004 (RLS135).
Signals within the frequency range of the transceiver enter a band-pass filter consisting of coils L1013 and L1016,
capacitors C1060, C1064, and C1067, then amplified by
Q1015 and enter a Varactor-tuned band-pass filter consisting of coils L1021 & L1022, capacitors C1106, C1107,
C1108, C1120, & C1221, and diodes D1025 & D1026 (both
HVC355B), before first mixing by Q1022 (3SK318).
Buffered output from the VCO is amplified by Q1007
(2SC5006) to provide a pure first local signal between
134.35 and 141.575 MHz for injection to the first mixer
Q1022 (3SK318).
The 21.7 MHz first mixer product then passes through
monolithic crystal filter XF1001/XF1002 to strip away all
but the desired signal, which is then amplified by Q1024
(2SC4915). The amplified first IF signal is applied to FM
IF subsystem IC Q1026 (BA4116FV), which contains the
second mixer, second local oscillator, limited amplifier,
noise amplifier, and RSSI amplifier.
A second local signal is produced from the PLL reference/
second local oscillator of X1001 (21.25 MHz). The 21.25
MHz reference signal is delivered to mixer section of FM
IF subsystem IC Q1026 (BA4116FV) which produce the
450 kHz second IF mixed with the first IF signal.
The second IF then passes through the ceramic filter
CF1001 to strip away unwanted mixer products, and is
then applied to the limited amplifier in the FM IF subsystem IC Q1026 (BA4116FV), which removes amplitude
variations in the 450kHz IF, before detection of the speech
by the ceramic discriminator CD1001.
2. Audio Amplifier
The demodulated audio signal from the Q1026
(BA4116FV) passes through a band-pass filter and Highpass filter, then applied to the de-emphasis of Q1005
(LM2902PWR). Then passes through the audio mute
switch Q1034 (SN74LVC1G66DCKR), the audio volume
VR1004 and the audio power amplifier Q1032 (TDA2822)
pin 7, providing up to 700 mW of audio power to the 16ohm loudspeaker.
3. Squelch Control
The squelch circuitry consists of a noise amplifier and
band-pass filter and noise detector within Q1026
(BA4116FV). When no carrier received, noise at the output of the detector stage in Q1026 (BA4116FV) is ampli-
fied and band-pass filtered by the noise amplifier section
of Q1026 (BA4116FV) and the network between pins 7
and 8, and then rectified by detection circuit in Q1026
(BA4116FV).
The resulting DC squelch control voltage is passed to pin
64 of the microprocessor Q1025 (UPD78F0484GK). If no
carrier is received, this signal causes pin 38 of Q1025
(UPD78F0484GK) to go low and pin 67 to go high. Pin 67
signals of Q1025 (UPD78F0484GK) to disable the supply
voltage to the audio amplifier Q1032 (TDA2822).
Thus, the microprocessor blocks output from the audio
amplifier, and silences the receiver, while no signal is being received (and during transmission, as well).
4. Transmit Signal Path
The speech input from the microphone MC1001 passes
through the audio amplifier Q1003 (NJM12902V), which
is adjusted the microphone gain. The speech signal passes through pre-emphasis circuit to Q1003 (NJM12902V),
which contains the IDC, and low-pass filter. Then passes
through VR1001 which allows manual adjustment of the
transmitter deviation level.
The filtered audio signal is applied to varactor diode
D1014 (HVC306B), which frequency modulates the VCO
Q1008 (2SC5006).
The modulated signal from the VCO Q1008 (2SC5006) is
buffered by Q1007 (2SC5006). The low-level transmit sig-
nal is then passes through the TX switching diode D1017
(DAN235E) to the buffer amplifier Q1016 (2SC5226),
driver amplifier Q1013 (RQA0004PXDQS), then amplified transmit signal is applied to the final amplifier Q1009
(RQA0011DNS) up to 5.0 watts output power.
The transmit signal then passes through the antenna
switch D1003 (RLS135) and is low-pass filtered to suppress harmonic spurious radiation before delivery to the
antenna.
7
Circuit Description
4-1 Automatic Transmit Power Control
Current from the final amplifier is sampled by C1011 &
C1022, and R1004 & R1008, and is rectified by D1002
(RB715F). The resulting DC is fed back through Q1004
(LM2904PWR) to the drive amplifier Q1013
(RQA0004PXDQS) and final amplifier Q1009
(RQA0011DNS), for control of the power output.
When the microprocessor selects “High” or “Low” power levels, pin 66 of Q1025 (UPD78F0484GK) to go low at
“High” power selected or pin 66 of Q1025
(UPD78F0484GK) to go high at “Low” power selected.
5. PLL Frequency Synthesizer
The PLL circuitry on the Main Unit consists of VCO Q1008
(2SC5006), VCO buffer Q1007 (2SC5006), PLL subsystem IC Q1021 (LV2105V), which contains a reference
divider, serial-to-parallel data latch, programmable divider, phase comparator and charge pump, and crystal X1001
which frequency stability is ±5 ppm @ –20 °C to +60 °C.
While receiving, VCO Q1008 (2SC5006) oscillates between 134.35 and 141.575 MHz according to the transceiver version and the programmed receiving frequency.
The VCO output is buffered by Q1007 (2SC5006), then
applied to the prescaler section of Q1021 (LV2105V). There
the VCO signal is divided by 64 or 65, according to a control signal from the data latch section of Q1021 (LV2105V),
before being sent to the programmable divider section of
Q1021 (LV2105V).
The data latch section of Q1021 (LV2105V) also receives
serial dividing data from the microprocessor Q1025, which
causes the pre-divided VCO signal to be further divided
in the programmable divider section, depending upon the
desired receive frequency, so as to produce a 25.0 kHz
derivative of the current VCO frequency.
Meanwhile, the reference divider sections of Q1021
(LV2105V) divides the 21.25 MHz crystal reference from
the reference oscillator section ofQ1021 (LV2105V), by 850
to produce the 25.0 kHz loops reference.
The 25.0 kHz signal from the programmable divider (derived from the VCO) and that derived from the reference
oscillator are applied to the phase detector section of
Q1021 (LV2105V), which produces a pulsed output with
pulse duration depending on the phase difference between
the input signals.
This pulse train is filtered to DC and returned to the Varactor D1011 and D1012 (both HVC350B).
Changes in the level of the DC voltage applied to the Varactor, affecting the reference in the tank circuit of the VCO
according to the phase difference between the signals
derived from the VCO and the crystal reference oscillator.
The VCO is thus phase-locked to the crystal reference oscillator. The output of the VCO Q1008 (2SC5006) after
buffering by Q1007 (2SC5006) is applied to the first mix-
er as described previously.
For transmission, the VCO Q1008 (2SC5006) oscillates
between 156.025 and 157.425 MHz according to the model version and programmed transmit frequency. The remainder of the PLL circuitry is shared with the receiver.
However, the dividing data from the microprocessor is
such that the VCO frequency is at the actual transmit frequency (rather than offset for IFs, as in the receiving case).
Also, the VCO is modulated by the speech audio applied
to D1014 (HVC306B), as described previously.
6. Miscellaneous Circuits
Push-To-Talk Transmit Activation
When the PTT switch on the Main Unit is closed, pin 72 of
Q1025 (UPD78F0484GK) goes low. This signal disables
the receiver by disabling the 5 V supply bus at Q1011
(UMD5N) to the front-end, FM IF subsystem IC Q1026
(BA4116FV).
At the same time, Q1010 (UMD5N) activate the transmit 5
V supply line to enable the transmitter.
8
Alignment
The HX280S/E has been carefully aligned at the factory
for the specified performance across the marine band.
Realignment should therefore not be necessary except in
the event of a component failure.
All component replacement and service should be performed only by an authorized STANDARD HORIZON
representative, or the warranty policy may be voided.
The following procedures cover the sometimes critical and
tedious adjustments that are not normally required once
the transceiver has left the factory. However, if damage
occurs and some parts are replaced, realignment may be
required. If a sudden problem occurs during normal operation, it is likely due to component failure; realignment
should not be done until after the faulty component has
been replaced.
We recommend that servicing be performed only by authorized STANDARD HORIZON service technicians who
are experienced with the circuitry and fully equipped for
repair and alignment. Therefore, if a fault is suspected,
contact the dealer from whom the transceiver was purchased for instructions regarding repair. Authorized
STANDARD HORIZON service technicians realign all circuits and make complete performance checks to ensure
compliance with factory specifications after replacing any
faulty components. Those who do undertake any of the
following alignments are cautioned to proceed at their
own risk.
Problems caused by unauthorized attempts at realignment
are not covered by the warranty policy. Also, STANDARD
HORIZON must reserve the right to change circuits and
alignment procedures in the interest of improved performance, without notifying owners. Under no circumstances
should any alignment be attempted unless the normal
function and operation of the transceiver are clearly understood, the cause of the malfunction has been clearly
pinpointed and any faulty components replaced, and the
need for realignment determined to be absolutely necessary. The following test equipment (and thorough familiarity with its correct use) is necessary for complete realignment. Correction of problems caused by misalignment resulting from use of improper test equipment is
not covered under the warranty policy. While most steps
do not require all of the equipment listed, the interactions
of some adjustments may require that more complex adjustments be performed afterwards. Do not attempt to
perform only a single step unless it is clearly isolated electrically from all other steps. Have all test equipment ready
before beginning, and follow all of the steps in a section
in the order presented.
Required Test Equipment
RF Signal Generator with calibrated output level at
200 MHz
Frequency Counter: >0.1 ppm accuracy at 200 MHz
AF Signal Generator
Deviation Meter (linear detector)
VHF Sampling Coupler
Inline Wattmeter with 5% accuracy at 200 MHz
50-ohm Non-reactive Dummy Load: 10W at 200 MHz
7.4 VDC, 2A Regulated DC Power Supply
IBM® PC/compatible computer with Microsoft® Win-
dows® 2000, XP, or Vista
Standard Horizon HX280 Service Flag Controller and
Alignment Jig.
Alignment Preparation & Precautions
A dummy load and inline wattmeter must be connected
to the main antenna jack in all procedures that call for
transmission, except where specified otherwise. Correct
alignment is not possible with an antenna. After completing one step, read the following step to determine whether the same test equipment will be required. If not, remove the test equipment (except dummy load and wattmeter, if connected) before proceeding.
Correct alignment requires that the ambient temperature
be the same as that of the transceiver and test equipment,
and that this temperature be held constant between 20 °C
and 30 °C (68 °F ~ 86 °F). When the transceiver is brought
into the shop from hot or cold air it should be allowed
some time for thermal equalization with the environment
before alignment. If possible, alignments should be made
with oscillator shields and circuit boards firmly affixed
in place. Also, the test equipment must be thoroughly
warmed up before beginning.
Note: Signal levels in dB referred to in this procedure are
based on 0 dBμ = 0.5 μV(closed circuit).
9
Alignment
Before Alignment
Install the HX280 Service Flag Controller Program to
your computer.
Remove the Front Panel from the transceiver accord-
ing to the following procedures:
1) Disconnect the antenna from the transceiver.
2) Remove the VOL knob and Battery Pack from the
transceiver
3) Remove the two screws which located at the bottom side on the battery compartment.
4) Carefully pull out the chassis from the Front Panel.
Refer to the “Exploded View“ on the page 4.
Set up the test equipment as shown below, and set the
DC Power Supply voltage to 7.4 V.
Execute the HX280 Service Flag Controller Program.
Select the COM port number which is connected to
the HX280 Alignment Jig.
Press and hold in the [PRESET] key
while turning the transceiver on to
enter the Alignment Mode.
Select “Alignment ON” Radio But-
ton of the HX280 Service Flag Controller Program.
Click the left mouse button on the
[
SET] button of the HX280 Service
Flag Controller Program.
Main Reference Frequency Adjustment
Turn the Antenna switch to the “TX Alignment” side.
Remove the solder jumper JP1001.
Set the channel to CH16.
Use the [H/L] key to set the transceiver to “LOW”
power.
With the PTT switch pressed, adjust TC1001 so the
Frequency Counter reading is 156.800 MHz ± 100 Hz.
Transmit Power Adjustment
Turn the Antenna switch to the “TX Alignment” side.
Set the channel to CH16.
Increase the DC Power Supply voltage to 8.0 V.
Use the [H/L] key to set the transceiver to “HI” power.
With the PTT switch pressed, adjust VR1003 so that
RF output power is 5.0 W ± 0.1 W.
Release the PTT switch, then set the transceiver to
“LOW” power by the [H/L] key.
With the PTT switch pressed, adjust VR1002 so that
RF output power is 0.8 W ± 0.1 W.
Release the PTT switch.
Return the DC Power Supply voltage to 7.4 V.
Inline
Wattmeter
50
Dummy Load
Frequency
Counter
10
Ω
Power Supply
RF Sampling
Coupler
Regulated
( ) :
( ) :
( ) :
( ) :
VR1002
VR1003
VR1001
RED
RED
BLACK
BLACK
Antenna Switch
“RX” Alignment“TX” Alignment
HX280 Alignment Jig
RF Signal
Generator
Attention!
The HX280’s Audio output is BTL output.
16 1 W
Ω
Resistor
AF Signal
Generator
JP1001
TC1001
VR1005
TP1018
D-SUB 9-pin Jack
Alignment
TX Deviation Adjustment
Turn the Antenna switch to the “TX Alignment” side.
Confirm that the solder jumper JP1001 is removed.
Set the AF Signal Generator output to 200 mVrms at 1
kHz.
Set the channel to CH16.
With the PTT switch pressed, adjust VR1001 so that
the maximum deviation is 4.4 kHz ± 0.1 kHz.
Release the PTT switch.
Solder the jumper JP1001.
Squelch Level Adjustment
Turn the Antenna switch to the “RX Alignment” side.
Set the channel to CH16.
Set the RF Signal Generator output to 156.800 MHz,
at a level of +0 dBμ (HX280S) or +3 dBμ (HX280E),
±3.0 kHz deviation with a 1 kHz audio tone.
Connect the DC voltmeter to TP1018, adjust VR1005
so that DC voltmeter reading is 0.2 V ± 0.02 V (HX280S)
or 0.45 V ± 0.02 V (HX280E).
Software Alignment/Confirmation Mode
Overview of Software Alignment Mode
The “Software Alignment Mode” has been build in
the microprocessor in order to adjust and confirm the
performance of transceiver.
The purpose is to adjust transceiver simply and to con-
firm the performance of transceiver smoothly.
Starting Software Alignment Mode
Set the channel to CH16, then turn the VOL knob
counter clockwise to turn off the radio.
Turn the Antenna switch to the “RX Alignment” side.
Turn the VOL knob clockwise to
turn on the radio while press and
holding the [PRESET] keys. The
LCD will be shown the Alignment
mode “
Press the [SCAN] key. Then the LCD
will be shown the Alignment Item
(1st Item is Threshold “
Set the RF Signal Generator output
to 156.800 MHz, at a level of –8 dBμ (HX280S) or
–6 dBμ (HX280E), ±3.0 kHz deviation with a 1 kHz
audio tone.
Press the [PRESET] key to record a
threshold level.
Press the [MEM] key to save the new
setting.
ALAL
AL”.
ALAL
tHtH
tH”).
tHtH
Press the [SCAN] key to recall the
Alignment Item “
Set the RF Signal Generator output
to 156.800 MHz, at a level of +0 dBμ
(HX280S) or +3 dBμ (HX280E), ±3.0 kHz deviation
with a 1 kHz audio tone.
Press the [PRESET] key to record a
tight level.
Press the [MEM] key to save the new
setting.
This completes the Software Alignment Mode. To save
all settings and exit, press and hold the [16/9] key for one
second. Then turn off the transceiver.
tI tI
tI (TIGHT)”.
tI tI
After Alignment
Execute the HX280 Service Flag Controller Program
again.
Select the COM port number which is connected to
the HX280 Alignment Jig.
Press and hold in the [PRESET] key while turning
the transceiver on to enter the Alignment Mode.
Select “Alignment OFF” Radio But-
ton of HX280 Service Flag Controller Program.
Click the left mouse button on the
[
SET] button of the HX280 Service
Flag Controller Program.
Turn off the transceiver.
Assemble the transceiver while being carefully so that
Rubber Packing does not protrude from a Front Case.
Important Note: To ensure the radio is water proof,
make sure the gasket is installed on the chassis correctly and is not pinched when inserted into the front
case.
NOTICE
Do not touch the Alignment Item “
dCdC
dC”.
dCdC
11
Note
12
MAIN Unit
RX: 0 V
TX: 0.82 V
RX: 0 V
TX: 1.66 V
3.11 V
RX: 3.53 V
TX: 0 V
RX: 2.48 V
TX: 0 V
RX: 0 V
TX: 1.13 V
RF AMP
Q1015
RX: 4.18 V
TX: 0 V
RX: 0 V
TX: 0.91 V
RX: 1.09 V
TX: 0 V
RX: 0 V
TX: 2.83 V
BPF “LOW”: 0.01 V
BPF “HIGH”: 1.56 V
RX: 0 V
TX: 1.41 V
BPF “LOW”: 3.29 V
BPF “HIGH”: 0 V
RX: 2.54 V
TX: 0 V
RX: 2.33 V
TX: 0 V
VCO Input
1st Mixer
Q1022
RX: 0 V
TX: 2.21 V
RX: 4.67 V
TX: 0 V
RX: 3.92 V
TX: 0 V
IF AMP
Q1024
RX: 1.82 V
TX: 0 V
RX SIGNAL “Non”: 1.15 V
RX SIGNAL “40 dBμ”: 0.02 V
2nd Mixer / IF
Q1026
RX: 1.75 V
TX: 0 V
RX: 2.77 V
TX: 0 V
Circuit Diagram
RX: 7.35 V
TX: 0.40 V
7.40 V
2.28 V
3.44 V
1.93 V
RX: 0 V
TX: 4.78 V
RX: 4.90 V
TX: 0 V
4.12 V
RX: 0 V
TX: 3.29 V
RX: 3.29 V
TX: 0 V
RX: 1.69 V
TX: 3.37 V
1.78 V
3.30 V
RX: 2.75 V
TX: 1.84 V
RX: 6.62 V
TX: 7.12 V
RX: 1.41 V
TX: 1.41 V
RX: 3.29 V
TX: 0 V
7.39 V
0 V
13
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