Emtron North America DX1B User Manual
OPERATING MANUAL
EMTRON DX-1d
HF LINEAR AMPLIFIER
April 2003
Emtron
DIVISION OF EMONA ELECTRONICS PTY. LTD.
92-94 Wentworth Avenue, Sydney 2010, Australia
Tel. +612 92110988 Fax +612 92811508
www.emtron.com.au
DX-1d, Serial No…………
INITIAL SETTINGS FOR PLATE AND LOAD
CAPACITORS
TEST
FREQUENCY
28.600 MHz 10m
24.900 MHz 12m
21.200 MHz 15m
18.100 MHz 17m
14.200 MHz 20m
7.070 MHz 40m
3.600 MHz 80m
1.800MHz 160m
1.850 MHz 160m
1.900 MHz 160m
BAND FACTORY SETTINGS
50 OHM LOAD
PLATE LOAD PLATE LOAD
USER SETTING
ANTENNA
TABLE 1
2
TABLE OF CONTENTS
1 GENERAL DESCRIPTION.........................................................................................................................................................5
1.1 DX-1D – INTERNAL VIEW ........................................................................................................................................................6
2 TECHNICAL SPECIFICATIONS..............................................................................................................................................7
3 UNPACKING.................................................................................................................................................................................8
3.1 OPENING THE CARTON ..............................................................................................................................................................8
3.2 OPENING THE DX-1D COVER....................................................................................................................................................8
3.3 REMOVING THE PACKING BLOCK..............................................................................................................................................8
4 INSTALLATION ENVIRONMENT...........................................................................................................................................9
4.1 REQUIRED ENVIRONMENT ........................................................................................................................................................9
4.2 POWER REQUIREMENTS ............................................................................................................................................................9
5 REAR PANEL................................................................................................................................................................................9
5.1 POWER / EARTH CONNECTIONS ................................................................................................................................................9
5.2 RF CONNECTIONS .....................................................................................................................................................................9
5.3 TRANSCEIVER CONTROL ...........................................................................................................................................................9
6 FRONT PANEL ...........................................................................................................................................................................10
6.1 CONTROLS ..............................................................................................................................................................................10
6.2 DISPLAYS................................................................................................................................................................................10
7 ELECTRICAL CONNECTIONS..............................................................................................................................................12
7.1 CONNECTIONS TO TRANSCEIVER / EXCITER...........................................................................................................................12
7.2 EARTH AND MAINS CONNECTIONS..........................................................................................................................................12
7.3 THE POWER CABLE (EXPORT VERSION) ..................................................................................................................................12
7.4 OPERATION AT 230V, 220V, 200V, 100V AND 120V (EXPORT VERSION).............................................................................12
8 DX-1D DESCRIPTION...............................................................................................................................................................14
8.1 RF SECTION ............................................................................................................................................................................14
8.2 MAINS TRANSFORMER............................................................................................................................................................14
8.3 H. V. POWER SUPPLY .............................................................................................................................................................14
8.4 SOFT START MODULE ..............................................................................................................................................................14
8.5 SENSOR MODULE ....................................................................................................................................................................14
8.6 ANTENNA RELAY / QSK MODULE ..........................................................................................................................................14
8.7 DISPLAY BOARD .....................................................................................................................................................................15
8.8 CONTROLLER BOARD..............................................................................................................................................................15
9 POWERING UP...........................................................................................................................................................................16
10 OPERATION ...........................................................................................................................................................................16
10.1 TUNNING PROCEDURE ....................................................................................................................................................16
10.1.1 General...........................................................................................................................................................................16
10.1.2 Preliminary tuning.........................................................................................................................................................16
10.1.3 Final tuning....................................................................................................................................................................17
10.1.4. Potential problems during tuning......................................................................................................................................18
10.2 ALC ADJUSTMENT ............................................................................................................................................................18
10.3 USING YOUR DX-1D...........................................................................................................................................................19
10.3.1 CW / RTTY and all digital modes..................................................................................................................................19
10.3.2 Voice modes (SSB).........................................................................................................................................................19
10.3.3 Hints on good linearity and efficiency ..........................................................................................................................19
11 SWITCHING THE POWER OFF.........................................................................................................................................20
12 TROUBLESHOOTING - IF SOMETHING GOES WRONG ..........................................................................................20
12.1 NO POWER ..............................................................................................................................................................................20
12.2 FAN NOT WORKING .................................................................................................................................................................20
12.3 IF THE FAULT LIGHT TURNS ON ............................................................................................................................................20
3
OVER-TEMPERATURE CUT-OFF ...............................................................................................................................................20
12.4
12.5 OVER-CURRENT CUT-OFF .......................................................................................................................................................21
12.6 IG2 BLINKS FAST - NO PLATE VOLTAGE..................................................................................................................................21
12.7 SPARKS / DISCHARGES IN RF AREA........................................................................................................................................21
12.8 SWR CUT-OFF.........................................................................................................................................................................21
12.9 FREQUENT OVER-DRIVE PROTECTION CUT-OFF......................................................................................................................21
12.10 TUBE REPLACEMENT ..........................................................................................................................................................21
13 WARRANTY / SERVICE ......................................................................................................................................................21
14 GLOSSARY..............................................................................................................................................................................22
15 APPENDIX 1: SCHEMATIC DIAGRAMS .........................................................................................................................23
15.1 DX-1D BLOCK DIAGRAM .......................................................................................................................................................23
15.2 CIRCUIT DIAGRAM – HIGH VOLTAGE POWER SUPPLY.................................................................................................24
15.3 CONTROL BOARD AND ADJUSTMENT POINTS ........................................................................................................................25
15.4 CIRCUIT DIAGRAM – AC INPUT AND WIRING DIAGRAM – STANDARD........................................................................26
15.5 CIRCUIT DIAGRAM – AC INPUT AND WIRING DIAGRAM – U.S. VERSION ...................................................................27
15.6 CIRCUIT DIAGRAM – SOFT START (200 TO 240 V OPERATION)....................................................................................28
15.7 CIRCUIT DIAGRAM – QSK......................................................................................................................................................29
15.8 CIRCUIT DIAGRAM – RF MODULE.......................................................................................................................................30
15.9 CIRCUIT DIAGRAM – CONTROL BOARD............................................................................................................................31
15.10 CONTROL BOARD – COMPONENT LEGEND (SILKSCREEN TOP) ...................................................................................32
CONTROL BOARD – SOLDER SIDE TRACK WORK ...............................................................................................................................33
16 APPENDIX 2: WAVEFORMS ..............................................................................................................................................34
16.1 QSK (OPTIONAL MODULE) SWITCHING .................................................................................................................................34
16.2 LINEARITY ..............................................................................................................................................................................34
17 APPENDIX 3: ADJUSTMENTS ...........................................................................................................................................35
17.1 CONTROL BOARD..............................................................................................................................................................35
17.1.1 PRE-BIAS ADJUSTMENT (Adjustment: POT7, marked PRE_BIAS) .........................................................................35
17.1.2 BIAS ADJUSTMENT (Adjustment: POT3, marked BIAS) ...........................................................................................35
17.1.3 SWR Protection adjustment...........................................................................................................................................36
17.1.4 EBS ADJUSTMENT (Adjustment: POT4, marked EBS). .............................................................................................36
17.1.5 SCREEN VOLTAGE ADJUSTMENT (Adjustment: POT2, marked SCREEN)............................................................36
17.1.6 SCREEN CURRENT LIMIT ADJUSTMENT (Adjustment: POT1, IG2LIMIT)..........................................................37
17.1.7 IPTRIP ADJUSTMENT (Adjustment: POT6, marking: IP TRIP)................................................................................37
17.2 DISPLAY BOARD ADJUSTMENTS ..................................................................................................................................39
17.2.1 PLATE CURRENT (Adjustment: VR4, Marked: AMP)................................................................................................39
17.2.2 PLATE VOLTATE (Adjustment: VR2, marked: VOLT)................................................................................................39
17.2.3 REFLECTED POWER (Adjustment: VR3, marked: RF R)..........................................................................................39
17.2.4 FORWARD POWER (Adjustment: VR1, marked: RF F) .............................................................................................39
17.2.5 SCREEN CURRENT (Adjustment: VR6, marked IG2+, VR5, marked IG2-)..............................................................39
17.3 RF SENSOR ADJUSTMENT ...............................................................................................................................................40
4
DX-1d LINEAR AMPLIFIER
Serial No …………
OPERATING MANUAL
April 2003
CAUTION
The DX-1d has been designed for 100% safe operation and long life.
Interlocking sensing circuitry constantly monitors conditions inside the
amplifier. It must be noted however, that the high voltages present inside
the DX-1d are EXTREMELY DANGEROUS. Do not remove the top cover
under any circumstances if any leads are still plugged into the rear of the
amplifier
- especially if the AC lead is plugged in the power outlet. Before
any component inside the high voltage, power supply or output section is
touched, unplug all rear panel leads and allow at least 5 minutes of 'off
time'. After that, you should further check this by momentarily shorting the
tube anode to the chassis with a suitable insulated lead.
1 GENERAL DESCRIPTION
The Emtron DX-1d Linear Amplifier is a 750 watt average output power, for the 160m through 10m amateur bands
housed in a desk-top cabinet with self-contained power supply and cooling system.
It utilises a single high performance tetrode, type GU74B (4CX800A), a ceramic metal tube with a plate dissipation of 800W. The
tube is air cooled by a commercial grade forced air turbine blower system.
Tetrodes offer exceptionally stable operation and levels of quality performance far exceeding that which can be expected from
triodes. The harmonic output and intermodulation distortion achieved with this tube are exceptionally low. This is especially
important when dealing with a high output power.
The Emtron DX-1d is supplied as standard with a host of features including mixed analogue and solid state metering,
comprehensive
In addition, a unique Emtron QSK module is available as an option. With this installed, extremely rapid switching times between
transmit and receive are possible, with consequent advantages when using CW or the digital modes.
Operation of the DX-1d is greatly simplified by a minimum of meter switching, and the absence of front panel level setting
controls. The front panel moving LED display systems indicate the screen grid current (positive and negative), while 5 single
LED’s indicate: Ready, Overdrive warning, High SWR cut-off indication, On Air and Fault. An analogue panel meter shows the
plate current, and the second analogue panel meter measures the plate voltage, the output power or the reflected power, depending
on the position of the switch marked “Meter”. In normal operation this switch is left in Po position, which means that all the
important operational parameters are simultaneously displayed, with no need for switching meters.
The Emtron Electronic Bias Switch (EBS) automatically switches the standing current (typically 0.3 A) off when there is no
modulation. This reduces the average tube dissipation.
On initial switch on, the unique Emtron "soft start" circuitry ensures that no damaging AC surge currents are generated.
Professional, fine output tuning adjustment is possible, due to the 6: 1 reduction mechanism fitted.
protection systems and indefinite duty cycle (continuous commercial service).
(9 bands),
5
1.1 DX-1d – Internal View
CORS
The main components of a DX-1d amplifier are shown in the picture below.
DISPLAY
SAFETY
MI
CONTROL
BOARD
WITCH
HIGH VOLTAGE
POWER SUPPLY
SOFT START
BLOWER
RF SENSOR
ANT. RELAY
RF CHOKE
Temperature Sensor
Tetrode GU84B
(4CX800)
TANK COIL,
10-30 m
TANK COIL,
40 -160 m
POWER
ON / OFF
STANDBY /
OPERATE
SWITCH
BAND
SELECTOR
6
PLATE
TUNING
LOAD
TUNING
BAND
SWITCH
2 TECHNICAL SPECIFICATIONS
FREQUENCY COVERAGE: Complete (manually tuned) coverage of the nine HF amateur bands:
1.800 – 1.900 MHz
3.500 – 4.000 MHz
7.000 – 7.500 MHz
14.000 – 14.350 MHz
18.000 – 18.500 MHz
21.000 – 21.500 MHz
24.000 – 24.500 MHz
28.500 – 29.990 MHz
TRANSMITTING MODES: Both continuous and low duty cycle modes are supported. That is, the DX-1d
supports SSB, CW, AM, FM, RTTY and SSTV. II
OUTPUT POWER: Typical 750 watts carrier or up to 1000 W PEP
DRIVE POWER: Nominal 40-60 watts for full rated output.
INPUT IMPEDANCE: Nominal 50 ohm passive impedance, unbalanced. VSWR 1.4:1 or less.
OUTPUT IMPEDANCE: Nominal 50 ohm passive impedance, unbalanced. VSWR 2.6:1 or less.
DISTORTION: Third order intermodulation products are more than 35 dB below rated output.
HARMONICS: Harmonic output is better than 50dB below the rated output.
FAULT PROTECTION: The comprehensive fault protection systems include circuitry to monitor:
• plate current: should the plate current exceed a safe value, the amplifier goes to standby mode for 2
minutes.
• screen grid over-current: Absolute tube protection is offered with visual warning and a reduced power
level being enabled if the screen current exceeds a pre-set limit.
• temperature: Should the tube's temperature exceed a specific level, amplifier operation is suspended
until the temperature drops to a safe level.
OPERATIONAL PROTECTION
• Overdrive protection: Should the DX-1d be overdriven, a LED warning indictor will light up when the
linearity limit is reached. If the drive is increased further, a 2 second cut off (by-pass) will follow.
• SWR protection: Should the DX-1d sense an SWR exceeding 2.6:1, a LED warning indicator will
light up, simultaneously with a 3 second cut off.
METERING: The front panel moving LED display systems indicate:
“Moving light” LED indicators:
• output power
• reflected power
• screen grid current
• plate voltage
• plate current
Five single LED’s:
7
• on air
• ready
• fault
• overdrive warning
• SWR cut-off indicator
ALC: Negative going, adjustable output level.
EBS: Electronic Bias Switch - automatically switches the standing current (about 0.3 A) to a lower ("pre-
bias") value - when there is no input drive.
PRE-BIAS: A small current will flow in the tube when the amplifier is keyed on, but there is no modulation.
This will prevent a harsh sound at the beginning of each word, when the EBS is activated and the tube goes
through a non-linear zone, before reaching the correct initial bias.
QSK: is an option that makes possible the antenna switching at very fast rate - typically 3ms switching time
in each direction. FACTORY INSTALLED ONLY.
SOFT START: when switched on, the mains power is gradually applied to the transformer, over a period of
about 5 seconds, to avoid the high in-rush current typical for such high loads.
COOLING: forced air cooling.
OPERATING TEMPERATURE: 0 to 40° Celsius
FUSING: Two 15A normal acting fuses on the rear panel
DIMENSIONS: 380mm wide, 180mm high, 380mm deep
WEIGHT: 20kg (44 lb) unpacked
3 UNPACKING
The DX-1d is packed in a heavy duty package easily sufficient to protect the amplifier during transportation,
even in case of fairly rough handling. The weight of the commercially rated mains transformer does mean,
however, that dropping the amplifier would without doubt result in some damage.
3.1 Opening the carton
When opening the packing, do not cut the carton. Save the packing material for possible further re-use.
Shipment of your DX-1d in other than factory packing may result in non-warranty damage.
3.2 Opening the DX-1d cover
An inspection of the interior of the amplifier should reveal no damage or adversely affected components.
Remove the 4 screws on each side and remove the cover. Should there be any form of problem, notify your
supplier immediately.
3.3 Removing the packing block
Assuming all is well, remove the block of foam from the amplifier bay and check that the amplifier tube is
firmly pressed home. Make sure the temperature sensor above the tube is in horizontal position or
slightly up position. If the sensor is bent down and touches the tube or if comes too close to the tube, the
plate high voltage will be shorted and damage could occur. Replace the cover and secure all four screws that
hold the cover in place.
8
4 INSTALLATION ENVIRONMENT
4.1 Required environment
The DX-1d amplifier can be operated at an ambient temperature between 0 and 40° Celsius. It should be
installed in a place with good ventilation and protected from the direct sunlight. At least 5 cm of free space
must be left at the left and right of the amplifier for ventilation. Do not place any object on top of the
amplifier, especially above the ventilation opening.
An environment free of dust, smoke and high humidity is required, as for any high powered RF amplifier.
Dust or particles resulting from burning fire wood or coal could be responsible for sparks or electrical
discharges between the capacitor plates, or in other parts of the RF section.
4.2 Power requirements
When operating at full power, up to 9A from the 240 VAC mains is required. Ensure that the AC supply you
intend to use is fully rated and properly fused. The Emtron "soft start" circuitry ensures that there are no
momentary surges of current at power-up, therefore the fuse does not need to be over-rated. However, the
wiring of the mains supply for the amplifier should be able to handle the power at full load with minimal drop
in the voltage, to insure the performance of your DX-1d does not suffer.
5 REAR PANEL
The following connectors and controls are present on the rear panel
5.1 Power / Earth connections
A wing-nut Earth connection is provided at the rear of DX-1d. A good Earth link must be provided here.
Connect this first, before making any other connection to the amplifier. Two fuse holders are fitted along with
15A, normal acting fuses.
5.2 RF connections
RF INPUT
The RF input is an SO-239 female connector. A 50 ohm coaxial cable line of good quality terminated with a
PL-259 coaxial connector is required to connect the transceiver or exciter output to the input connector of
your DX-1d amplifier.
RF OUTPUT
The RF output is also a female SO-239 connector. The use of a high quality RG-8A/U, RG-213 or similar 50
ohm coaxial cable line terminated with a ‘VHF’ type PL-259 connector is essential. Similarly, a VSWR of
2.6: 1 or better is mandatory. Remember too, that the EMTRON DX-1d amplifier can deliver 750 W
continuously and up to 1 kW PEP in the SSB mode. Not all antennas can handle such power.
5.3 Transceiver control
ALC
The ALC output is via a black female RCA connector.
This is an ALC system for use with transceivers or transmitters having a negative-going ALC system and
possessing an external ALC input jack. A shielded patch lead with an appropriate connector at one end and a
male RCA connector for the DX-1d at the other end is required. Check the specifications of your transceiver
for a suitable connection.
PTT
9
The PTT input is a female RCA connector (red). This line controls the transmit / receive switching system.
This jack must be connected to transceiver or exciter relay contacts which are open on RECEIVE and closed
on TRANSMIT. In the standard version (DX-1d fitted with a l2V antenna relay), the PTT input presents an
open circuit voltage of + l2V with respect to the chassis, with an impedance of about 70 ohm. Therefore, a
current of typically 0.17 A must be switched by the transceiver or exciter.
In the QSK version, the voltage at the PTT input is typically 28V loaded (up to 35V unloaded), with an
impedance of about 240 ohm. A current of about 0.12 A has to be switched in this case.
ALC CONTROL
This is a user-accessible control for setting the negative voltage at the ALC output. Further details are given
in section 10.2
6 FRONT PANEL
The following controls and indicators are present on the front panel:
6.1 Controls
BAND SWITCH
A nine position switch selects the desired frequency range. The operating bands are indicated in metres.
PLATE TUNE
Tunes the amplifier operating frequency. A chart of approximate starting settings is given in Table-1
LOAD TUNE
Tunes the amplifier output loading. A chart of approximate starting settings is given in Table-1
ON/OFF
Switches the AC power on and off. On initial switch on, the standby mode is enabled. Note also the
appropriate switch down sequence, given in Section 11.
OPR/STBY
Enables the amplifier once it has warmed up. In STANDBY mode, the screen voltage is removed and any RF
power applied to the input, is bypassed to the output. If this switch is changed to OPERATE before the
READY light comes on, the FAULT light will turn on. This is not a fault, but it is better to leave the switch in
STBY position until the amplifier is ready to operate.
6.2 Displays
Output Power - Scale up to 1 kW, non linear.
Reflected Power - Scale up to 150W, non linear.
Plate Voltage - Scale up to 3kV
Ig2 - Zero-centred display. The left (green) side has a full scale of about 25 mA of negative screen current.
The right (red) side has a full scale of about 35 mA of positive screen current. Above this value, the red LEDs
will flash, warning you to increase the loading, or reduce the drive. At about 40 mA, the protective current
limiting will cut in.
Plate Current - Scale up to 1.5A.
ON Air - single LED, green. When pressing PTT, this LED turns on (while in OPERATE)
10
READY - single LED, yellow. Turns on at the end of warm-up period, when the mains power to DX-1d is
switched on. It turns off for about 2 minutes if the plate current protection is triggered. In this case, the
FAULT light also turns on.
FAULT - single LED, red. Turns on in 3 situations:
• when the over-temperature protection is triggered, the FAULT turns on until the tube cools to a safe
level. During this time, the operation of the amplifier is disabled, the screen voltage is off and any RF
power applied to the input is bypassed directly to the output.
• when the over-current protection is triggered, FAULT turns on for 2 minutes, while READY turns off
• at DX-1d power up, if the OPR/STBY switch on the front panel is left in OPR position. The FAULT
light will go off when the DX-1d is ready for operation, after warm-up.
SWR - single LED, red. A three second cut-off will happen if your antenna has a SWR worse than 2:1
(typical 2.6:1) at the operating frequency. During the cut-off, the RF from the input is directly by-passed to
the output.
OVER-DRIVE - single LED, yellow. Flashes when the input drive is exceeding the linear operation level. If
even more drive is applied, the overdrive protection will cut off the operation for about 2 seconds.
NOTE: the input drive at which the indicator turns on depends on a certain extent on the tuning of the
amplifier.
RF OUTPUT POWER (kW)
OVER
DRIVE
Ig2
PLATE VOLTAGE (kV)
SWR
ON AIR
READY
PLATE CURRENT (A)
FAULT
Figure 1. Front Panel Display
11
7 ELECTRICAL CONNECTIONS
(Op
)
7.1 Connections to Transceiver / Exciter
Signal connections
Before making any connections, ensure that DX-1d is not connected to AC power, and the transceiver is not
transmitting. Connect the antenna first to the DX-1d output. Then connect the transceiver output to the DX-1d
RF input. Plug the PTT lead into the RCA socket marked PTT on the rear panel. If required, connect the
ALC.
The most appropriate interconnection layout is shown in Figure 1 below. In this set-up, the transmit/receive
relays in the DX-1d are controlled directly by the transceiver or exciter.
TO ANTENNA
EMTRON
DX-1d
RF
RF
IN
PTT
Relay
Input
ALC
OUT
tional
RF
OUT
ALC
Station
Transceiver
PTT
Relay
Output
Figure 2. Connections between DX-1d and Station Transceiver
7.2 Earth and mains connections
Power connections
Before connecting any power to the amplifier, make a good Earth connection to the screw with wing nut at
the rear of DX-1d. Make sure the POWER switch on the front panel is in the OFF position. Then plug the
power cable into the power point.
7.3 The power cable (export version)
As different countries have different standards for their power connections, the DX-1d amplifiers exported
from Australia are supplied without power cables. A power cable with IEC termination on one end and the
local type of plug needs to be fitted.
7.4 Operation at 230V, 220V, 200V, 100V and 120V (export version)
The Emtron DX-1d will normally arrive pre-set for the power source of the country the amplifier has been
sold to. However if operation to another mains voltage is required, the appropriate connection changes will be
needed.
Figure 2 shows the transformer connections for 120V, 200V, 220V, 230V and 240V operation. If a change is
required, this should be done only by a qualified technician, after taking all the necessary safety precautions.
See CAUTION on page 1.
PLEASE NOTE: For 120V operation, the fuse rating is 20A. Also, the QSK module needs a
modification, the DX-1db should be ordered for 120V operation.
12
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