VHF FM Transceiver
VX-2500V
Service Manual
2003 VERTEX STANDARD CO., LTD. (EC031N90A)
©
VERTEX STANDARD CO., LTD.
4-8-8 Nakameguro, Meguro-Ku, Tokyo 153-8644, Japan
VERTEX STANDARD
US Headquarters
10900 Walker Street, Cypress, CA 90630, U.S.A.
International Division
8350 N.W. 52nd Terrace, Suite 201, Miami, FL 33166, U.S.A.
YAESU EUROPE B.V.
P.O. Box 75525, 1118 ZN Schiphol, The Netherlands
YAESU UK LTD.
Unit 12, Sun Valley Business Park, Winnall Close
Winchester, Hampshire, SO23 0LB, U.K.
VERTEX STANDARD HK LTD.
Unit 5, 20/F., Seaview Centre, 139-141 Hoi Bun Road,
Kwun Tong, Kowloon, Hong Kong
Introduction
This manual provides technical information necessary for servicing the VX-2500V Transceiver.
Servicing this equipment requires expertise in handling surface-mount chip components. Attempts by non-qualified
persons to service this equipment may result in permanent damage not covered by the warranty, and may be illegal in
some countries.
Two PCB layout diagrams are provided for each double-sided circuit board in the transceiver. Each side of thr board is
referred to by the type of the majority of components installed on that side (“leaded” or “chip-only”). In most cases one
side has only chip components, and the other has either a mixture of both chip and leaded components (trimmers, coils,
electrolytic capacitors, ICs, etc.), or leaded components only.
While we believe the technical information in this manual to be correct, Vertex Standard assumes no liability for damage
that may occur as a result of typographical or other errors that may be present. Your cooperation in pointing out any
inconsistencies in the technical information would be appreciated.
Contents
Specifications .................................................... 2
DSUB 9-pin Accessory Connector ................. 3
Exploded View & Miscellaneous Parts ........ 4
Block Diagram................................................... 5
Interconnection Diagram ................................ 7
Circuit Description ........................................... 9
Alignment ..................................................... 11
RF Unit Jumper Information ..................... 16
Board Unit (Schematics, Layouts & Parts)
RF Unit ..........................................................................17
Panel Unit ..................................................................... 31
1
Specifications
General
Frequency range: 134-160 MHz (Type A)
148-174 MHz (Type C)
Number of Systems: 32
Number of Groups: 250
Number of Channels : 250 channels (Conventional)
640 channels (Trunking)
PLL Steps: 5.0 kHz/6.25kHz
Power Supply Voltage: 13.8V DC ±15 %
Channel Spacing: 12.5 / 25.0 kHz
Current Consumption (Approx.): TX: 6 A
RX: 700 mA
STBY: 250 mA
Operating Temperature range: –22 °F to 140 °F (–30 °C to +60 °C)
Frequency Stability: Better than ±2.5 ppm
RF Input-Output Impedance: 50 ohms
Audio Output Impedance: 4 ohms
Dimensions: 6.3 x 1.6 x 4.3 inch (160 x 40 x 110 mm)
Weight (Approx.): 1.87 lb (0.85 kg)
Receiver (Typical Values)
Circuit type: Double conversion Super-heterodyne
Sensitivity: 0.25 uV (12 dB SINAD)
Adjacent Channel Selectivity: 80/70 dB
Intermodulation: 75 dB
Spurious and Image Rejection: 90 dB
Audio Output: 4 W @ 4 ohms 5% THD
Audio Distortion: <3 % @1 kHz
Transmitter (Typical Values)
Power Output: 25 W (low: 5W)
Modulation: 16K0F3E, 11K0F3E
Max Deviation: 5.0/2.5 kHz
Conducted Spurious Emission: 70 dB below carrier
Audio Distortion: <3 % @ 1 kHz
Microphone type: Dynamic
Microphone impedance: 600 ohms
2
Pin 1: Output Logic squelch
High: Radio receiving the signal with the correct CTCSS, DCS, or LTR ID.
Low: Radio not receiving the signal with the correct CTCSS, DCS, or LTR ID.
Pin 2: Output Rx discriminator
JP3 (JP1503) - Flat: 10 Hz to 3.0 kHz (140 mVrms / STD deviation with 600 ohm termination)
JP4 (JP1504) - Filtered 300 Hz to 3.0 kHz (70 mVrms / STD deviation with 600 ohm termination)
* Note: JP3 is closed from the factory, and JP4 is not closed from the factory.
DSUB 9-pin Accessory Connector
or
Pin 3: Input TX data to the radio modulator. (Flat: 10 Hz to 3.0 kHz)
(40 mVrms / STD deviation)
Pin 4: Input DTR (to switch the radio operation between dispatch operation and Data mode)
[DTR Low: Turn on the Data transmission, less than 0.5 V]
[DTR High: Turn off the Data transmission, more than 4.0 V]
Pin 5: Ground
Pin 6: Output Horn alert signal (Open collector with maximum 16.0 V, 100 mA sink).
Pin 7: Input external PTT
[Low: Request the transmission]
[High: Request the Receiving]
Pin 8: Output supply voltage (Need to set the solder short on the PCB)
JP1 (JP1501) Output 5.0 V (Maximum 100 mA output)
or
JP2(JP1502) Output 13.8 V (Maximum 100 mA output)
* Both JP1 and JP2 are not closed from the factory.
Pin 9: Input the ignition signal of the CAR.
This signal is for the following operation,
(1) Disable the Horn alert during the ignition is turned on.
(2) Turn on and off the radio. This function requires the solder short JP8 (JP1508).
3
Exploded View & Miscellaneous Parts
CONNECTOR
WIRE ASSY
T9206634A
SUPPORT
RA0060700
†
BLIND SEET (70 x 10)
RA0365500
P1090654
SPONGE RUBBER (SHIELD)
†
„
RA0365500
REF.
VXSTD P/N
•
U20206002
‚
U20306002
ƒ
U20308002
„
U24306002
…
U24308001
†
U31206007
†
…
„
‚
•
‚
„
BINDING HEAD SCREW M2.6 x 6 NI
BINDING HEAD SCREW M3 x 6 NI
BINDING HEAD SCREW M3 x 8 NI
TAPTITE SCREW M3 x 6 NI
TAPTITE SCREW M3 x 8
OVAL HEAD SCREW M2.6 x 6 B
†
„
SHIELD GASKET
S5000238
DESCRIPTION
CASE
RA0060100
MAIN UNIT
QTY.
1
2
2
4
1
7
FERRITE BEADS
L9190001
VOL KNOB
RA0377000
PANEL ASSY
RA0376000
TUBE
RA0392000
PM HOLDER
RA0066400
IC
G1093557
BLIND SEET (4 x 3)
RA0405200
†
PANEL UNIT
BLIND SEET (4 x 3)
†
RA0405200
SPEAKER
M4090154
†
WIRE ASSY
T9206979
WIRE ASSY
T9206633
GAP PAD
S6000379
ƒ
CHASSIS
RA005600C
SP HOLDER
RA0378300
SPONGE RUBBER
RA0383600
ƒ
CONNECTOR
P1090984
SPONGE
RA0460200
4
Block Diagram (1)
5
Block Diagram (2)
6
Interconnection Diagram
7
Note
8
Circuit Description
1. Overview
The VX-2500V is a VHF FM mobile transceiver designed
to operate in the frequency range of 134 to 174MHz.
2. Circuit Configuration by Frequency
The receiver is a double-conversion superheterodyne with
a first intermediate frequency (IF) of 44.25MHz and a sec-
ond IF of 450kHz. Incoming signals from the antenna are
mixed with the local signal from PLL to produce the first
IF of 44.25MHz.
This is then mixed with the 43.8MHz second local oscilla-
tor (using the 14.6MHz reference crystal) output to pro-
duce the 450kHz second IF. This is detected to give the
demodulated signal.
The transmit signal frequency is generated by PLL VCO,
and modulated by the signal from the microphone. It is
then amplified and sent to the antenna.
3. Receive Signal Path
Incoming RF signals from the antenna connector are de-
livered to the RF Unit, and pass through a low-pass filter
(LPF) antenna switching network consisting of coils L1001,
L1002, L1003, L1005, and L1007, capacitors C1004,
C1009,C1016, C1019, and C1025, and antenna switching
diodes D1005 and D1007 (both UM9957F) for delivery to
the receiver front end.
Signals within the frequency range of the transceiver are
then passed through a varactor-tuned bandpass filter con-
sisting of L1008, L1009 before RF amplification by Q1011
(2SC4226).
The amplified RF is then band-pass filtered again by var-
actor-tuned resonators L1019, L1023 to ensure pure in-
band input to 1st mixer Q1026 (3SK228).
Buffered output from the VCO Unit is amplified by Q1021
(2SC5107) and low-pass filtered by L1030/L1032 and
C1184/C1188/C1192, to provide a pure 1st local signal
between 178.25 and 218.25MHz to the 1st mixer.
The 44.25MHz 1st mixer product then passes through dual
monolithic crystal filters XF1001 and XF1002, and is am-
plified by Q1029 (2SC4215Y) and delivered to the input
of the FM IF subsystem IC Q1028 (TA31136FN).
This IC contains the 2nd mixer, 2nd local oscillator, limit-
er amplifier, FM detector, noise amplifier, and squelch
gates.
The 2nd LO in the IF-IC is produced from crystal X1001
(14.600MHz), and the 1st IF is converted to 450kHz by the
2nd mixer and stripped of unwanted components by ce-
ramic filter CF1001 or CF1002. After passing through a
limiter amplifier, the signal is demodulated by the FM
detector CD1001 (CDBC450CX24).
Detected audio from Q1029 is applied to Q2016 (AK2345)
and audio low-pass filter. After volume adjustment by
Q2014 (M62364FP), the audio signal is amplified by the
AF power amplifier Q1509 (TDA2003H) and passed to
speaker jack.
4. Transmit Signal Path
Voice audio from the microphone is delivered via the MIC
(Jack) Unit to the PANEL Unit, after passing through
amplifier Q2022(NJM2902V), Mic gain-volume Q2014
(M62364FP) pre-emphasis Q2015 (NJM2902V), and lim-
iter Q2016 (IDC instantaneous deviation control), is ad-
justed for optimum deviation level and delivered to the
next stage.
Voice input from the microphone and CTCSS are FM-
modulated to the VCO of the synthesizer, while DCS au-
dio is modulated by the reference frequency oscillator of
the synthesizer.
Synthesizer output, after passing through diode switch
D1022 (1SS321), is amplified by driver Q1022
(2SC5415E), Q1025 (2SC5107) and power module Q1014
(RA30H1317M) to obtain full RF output. The RF energy
then passes through antenna switch D1005/D1007 and a
low-pass filter circuit and finally to the antenna connec-
tor.
RF output power from the final amplifier is sampled by
CM coupler and is rectified by D1011, D1012 (both
HSM88AS). The resulting DC is fed through Automatic
Power Controller Q1003 (M5223AGP), Q1002
(2SC4154E), Q1032 (2SC4254E), and TH1003 to trans-
mitter RF amplifier and thus the power output.
Generation of spurious products by the transmitter is min-
imized by the fundamental carrier frequency being equal
to the final transmitting frequency, modulated directly in
the transmit VCO. Additional harmonic suppression is
provided by a low-pass filter consisting of L1002, L1003,
L1005, C1004, C1009, C1016, C1019, and C1025, resulting
in more than 60dB of harmonic suppression prior to de-
livery to the RF energy to the antenna.
5. PLL Frequency Synthesizer
PLL frequency synthesizer consists of the VCO Q1013
(2SK508-K52: RX) and Q1015 (2SC4226-R24: TX), VCO
buffers Q1018, Q1020, Q1021 (all 2SC5107-0), PLL sub-
system IC Q1023 (SA7025DK) and 14.6MHz reference
crystal X1001.
The frequency stability is ±2.5ppm within temperature
range of –30 to +60 degree. The output of the 14.6MHz
reference is applied to pin 8 of the PLL IC.
While receiving, VCO Q1013 oscillates between 178.25 and
218.25MHz according to the transceiver version and the
programmed receiving frequency. The VCO generates
355.75 to 467.75MHz for providing to the first local sig-
nal. In TX, the VCO generates 134 to 174MHz.
9
Circuit Description
The output of the VCO is amplified by the Q1020 and rout-
ed to the pin 5 of the PLL IC. Also the output of the VCO
is amplified by the Q1021 and routed first local/Power
Module according to D1022.
The PLL IC consists of a prescaler, fractional divider, ref-
erence divider and phase comparator and charge pump.
This PLL IC is fractional-N type synthesizer and performs
in the 40 or 50 kHz reference signal, which is eighth of the
channel step (5 or 6.25 kHz). The input signal from pin 5
and 8 of the PLL IC is divided down to the 20 kHz and
compared at phase comparator. The pulsed output signal
of the phase comparator is applied to the charge pump
and transformed into DC signal in the loop filter. The DC
signal is applied to the VCO and locked to keep the VCO
frequency constant.
PLL data is output from "DCS_E" (pin100), "CLOCK"
(pin2) and "PLL_E" (pin98) of the microprocessor Q2013.
The data are input to PLL IC when the channel is changed
or when transmission is changed to reception and vice
versa. A PLL lock condition is always monitored by the
pin20 of the Q2013. When the PLL is unlocked, the UL
goes low.
6. Miscellaneous Circuits
6-1 DCS/LTR Demodulator
DCS signals are demodulated on the PANEL-UNIT, It is
demodulated by Q2116 (AK2345), amplifier Q2015, and
comparator Q2021.
6-2 CTCSS encoder/decoder
The CTCSS code is generation and encoding by CTCSS
encoder/decoder IC Q2016 (AK2345).
7. Power Supply Circuits
7-1 All 13.8V
13.8V is always supplied to Power AMP Q1014
(RA30H4452M). Switched 13.8V is supplied to AF Power
AMP Q1509 (TDA2003H) and 9V Regulator Q1004
(MM1216EN) and Q1005 (2SB1201STP).
7-2 All 9V
9V regulated from 13.8V by Q1004 (MM1216EN) and
Q1005 (2SB1201STP).
7-3 VCO 9V
9V is filtered by Ripple Filter and is supplied to VCO Os-
cillator Q1013 (2SK508-K52), Q1015 (2SC5107-O), and
VCO BUFFER AMP Q1015 (2SC5107-O).
7-4 5V (RF-UNIT)
5V in RF-UNIT is regulated by REGULATOR IC Q1024
(NJM78L05UA). 5V is supplied to PLL IC Q1023
(SA7025DK), FM IC Q1028 (TA31136FN), and Reference
Oscillator Q1027 (23C4116GR).
7-5 TX 9V
TX 9V is active on transmit. TX 9V is supplied to ANT SW
D1005, D1007 (UM9957F) and TX DRIVER Q1022
(2SC5415E), Q1025 (2SC5107-O).
7-6 RX 9V
RX 9V is active on receive. RX 9V is supplied to RX RF
AMP Q1026 (3SK228) and MIXER Q1011 (2SC4227-R34).
7-7 5V (RF-UNIT)
9V from RF-UNIT is regulated to 5V by REGULATOR IC
Q2006 (NJM78L05UA) in PANEL-UNIT.
6-3 MPU
Operation is controlled by 8-bit MPU IC Q2013
(LC87F72C8A). The system clock uses a 3.6864MHz crys-
tal for a time base. IC Q2003 (S-80735SN) resets the MPU
when the power is on, and monitors the voltage of the
regulated 5V power supply line.
6-4 DCS/LTR Encorder
The DCS code is generation and encoding by MPU IC
Q2013 (LC87F72C8A). It is filtered by Q2021 (NJM2902V)
and adjusted the level by Q2014 (M62364FP).
6-5 Compandor
The Compandor is active when Pin90 of Q2013
(LC87F72C8A) is “High”. When the Compandor is ac-
tive, MIC Audio is compressed, and detected audio is ex-
panded by Q2017 (LA8630M).
10
Alignment
Introduction
The VX-2500V is carefully aligned at the factory for the
specified performance across the frequency range speci-
fied for each version. Realignment should therefore not
be necessary except in the event of a component failure,
or altering version type. All component replacement and
service should be performed only by an authorized Ver-
tex Standard representative,or the warranty policy may
be void.
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 subsequently are placed, realign-
ment may be required. If a sudden problem occurs dur-
ing normal operation, it is likely due to component fail-
ure; realignment should not be done until after the faulty
component has been replaced.
We recommend that servicing be performed only by au-
thorized Vertex Standard service technicians who are ex-
perienced 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 Vertex Standard
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, Vertex Standard
reserves the right to change circuits and alignment proce-
dures in the interest of improved performance, without
notifying owners.
Under no circumstances should any alignment be attempt-
ed unless the normal function and operation of the trans-
ceiver are clearly understood, the cause of the malfunc-
tion has been clearly pinpointed and any faulty compo-
nents replaced, and realignment determined to be abso-
lutely necessary.
The following test equipment (and thorough familiarity
with its correct use) is necessary for complete realignment.
Correction of problems caused by misalignment result-
ing from use of improper test equipment is not covered
under the warranty policy. While most steps do not re-
quire all of the equipment listed, the interactions of some
adjustments may require that more complex adjustments
be performed afterwards.
Required Test Equipment
r RF Signal Generator with calibrated output level
at 500MHz
r Deviation Meter (linear detector)
r In-line Wattmeter with 5% accuracy at 1000MHz
r 50W RF Dummy Load with power rating 100W
at 500MHz
r 4W AF Dummy Load
r Regulated DC Power Supply (standard 13.8V
DC, 15A)
r Frequency Counter with 0.1ppm accuracy at
500MHz
r AC Voltmeter
r DC Voltmeter
r VHF Sampling Coupler
r IBM PC/compatible Computer
r Oscilloscope
r Vertex Standard VPL-1 Connection Cable &
Alignment program
Alignment Preparation & Precautions
A 50W RF Dummy Load and in-line 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 de-
termine whether the same test equipment will be required.
If not, remove the test equipment (except dummy load
and wattmeter, in 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 68°F
and 86°F (20°C ~ 30°C). When the transceiver is brought
into the shop from hot or cold air, it should be allowed
time to come to room temperature before alignment.
Whenever possible, alignments should be made with os-
cillator 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 the alignment pro-
cedure are based on 0dBm EMF = 0.5mV.
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.
11
Alignment
Transceiver
Setup the test equipment as shown below, apply 13.8V
DC power to the transceiver.
The transceiver must be programmed for use in the in-
tended system before alignment is attempted. The RF pa-
rameters are loaded from the file during the alignment
process.
Important
In order to facilitate alignment over the complete switch-
ing range of the equipment it is recommended that the
channel data in the transceiver is preset as the chart be-
low.
CHANNEL
CH 1
CH 2
CH 3
CH 4
CHANNEL
SPACE
Wide
Narrow
Wide
Wide
FREQUENCY (SIMPLEX
Version A
147.100 MHz
147.100 MHz
134.100 MHz
159.900 MHz
)
Ver. C
161.100 MHz
161.100 MHz
148.100 MHz
173.900 MHz
The alignment mode is accessed by “Alignment mode”
command from the computer whilst switching on. And it
is operated by the alignment tool automatically.
PLL VCV
Connect the positive lead of the DC voltmeter to
¦
the test point TP1007 (VCV) on the RF-Unit, as
indicated in the figure, and the negative lead to
chassis ground.
Set the transceiver to the high band edge fre-
¦
quency channel, then adjust coil L1017 on the
Unit for 7.25V on the voltmeter.
Key the transmitter, and adjust coil L1020 on the
¦
Unit for 7.25V on the voltmeter.
Next select to the low edge frequency channel
¦
and confirm above 2.00V to 3.00V on the volt-
meter.
Key the transmitter, and confirm above 2.00V to
¦
3.00V on the voltmeter.
PLL Reference Frequency
With the wattmeter, dummy load and frequency counter
connected to the antenna jack, and select band center fre-
quency channel, key the transmitter and adjust VR1001
on the RF-Unit, if necessary, so the counter frequency is
within 100 Hz of the channel center frequency for the trans-
ceiver version.
During the alignment mode, normal operation is suspend-
ed. Use the alignment tool program running on PC.
L1017
TP1007
12
L1020
VR1001
RF Unit Test & Alignment Points
Alignment
The alignment tool outline
Installation the tool
This alignment tool consists, MS-DOS based, only one ex-
ecute file “svc47.exe.“ You make a directly as you think
fit, and copy this file. That is all of the installation pro-
cess.
Boot the tool
Change directly and input in command line, “svc47 [en-
ter],“ and boot the alignment tool.
Preparation
Setup the test equipment as “Alignment Preparation &
Precautions.”
Set the RF Ch. List to Table 1 on the CE47 Clone editor
software.
Enter to the alignment mode
To enter the alignment mode, press “[0] Alignment Mode”
on the personal computer Key board. You turn off the
power of the transceiver, and turn on the transceiver. If
entry succeed,the alignment tool display as follows.
[0]Common TX
[1]Common RX
Action of the switches
When the transceiver is in alignment mode, the action of
[PTT], [MON], [UP], and [DOWN] is ignored. All of the
action is remote controlled by PC.
Menu of the tool
[0] Common TX
- [0] Tx Power High
This parameter is used to align TX High power (25W).
Press [Enter] on “[0] Tx Power High” to align
¦
TX High power.
Select the Channel “1“ in alignment range.
¦
Press the [Space] key on the keyboard to acti-
¦
vate the transmitter.
Press the [UP] or [DWN] key, as needed, to set
¦
the power output to the following specification,
as indicated on the external wattmeter.
Tx Power High: 25 W (±0.5W)
When the 25 Watt level is attained, press [Enter]
¦
to lock in the new data.
- [1] Tx Power Low
This parameter is used to align TX Low power (5W).
Press [Enter] on “[1] Tx Power Low” to align TX
¦
Low power.
Select the Channel “1“ in alignment range.
¦
Press the [Space] key on the keyboard to acti-
¦
vate the transmitter.
Press the [UP] or [DWN] key, as needed, to set
¦
the power output to the following specification,
as indicated on the external wattmeter.
Tx Power Low: 5 W (±0.1W)
When the 5 Watt level is attained, press [Enter]
¦
to lock in the new data.
- [2] VCO Deviation
This parameter is used to align the VCO Deviation.
Press [Enter] on “[2] VCO Deviation” to align
¦
VCO Deviation.
Select the Channel “1“ in alignment range.
¦
Adjust the AF generator output level to
¦
38mVrms (–26dBm) at 2 kHz to the pin 3 of the
J1502 (D-sub 9pin ).
Press the [Space] key on the keyboard to acti-
¦
vate the transmitter.
Press the [UP] or [DWN] key, as needed, to set
¦
the VCO Deviation (Wide) to the following speci-
fication, as indicated on the deviation meter.
When the desired deviation level is attained,
¦
press [Enter] to lock in the new data.
Select the Channel 2, and set the VCO Deviation
¦
(Narrow), same as Channel “1.“
VCO Deviation (Wide): 3.0 kHz (±0.1 kHz)
VCO Deviation (Narrow): 1.5 kHz (±0.1 kHz)
13
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