Subscribe to Our Youtube Channel
Related Manuals for Emtron DX-3
Summary of Contents for Emtron DX-3
- Page 1 OPERATING MANUAL EMTRON DX-3 HF LINEAR AMPLIFIER April 2005 Emtron DIVISION OF EMONA ELECTRONICS PTY. LTD. 92-94 Wentworth Avenue, Sydney 2010, Australia Tel. +612 92110988 Fax +612 92811508 www.emtron.com.au...
- Page 2 DX-3, Serial No………… INITIAL SETTINGS FOR PLATE AND LOAD CAPACITORS TEST BAND FACTORY SETTINGS USER SETTINGS FREQUENCY 50 OHM LOAD ANTENNA PLATE LOAD PLATE LOAD 28.600 MHz 24.900 MHz 21.200 MHz 18.100 MHz 14.200 MHz 10.125 MHz 7.070 MHz 3.600 MHz 1.800MHz...
-
Page 3: Table Of Contents
ARTH AND MAINS CONNECTIONS )......................12 ERMINATING THE POWER CABLE EXPORT VERSION 230V, 220V, 200V ( ) ...................... 12 PERATION AT EXPORT VERSION DX-3 DESCRIPTION ................................13 RF S ..................................13 ECTION ................................ 14 AINS TRANSFORMER H. V. P ................................. 14... - Page 4 REQUENT OVER DRIVE PROTECTION CUT 12.10 ..............................21 UBE REPLACEMENT WARRANTY / SERVICE ..............................21 GLOSSARY..................................22 APPENDIX 1: SCHEMATIC DIAGRAMS ........................23 15.1 DX-3 B ..............................23 LOCK IAGRAM 15.2 – HIGH VOLTAGE POWER SUPPLY....................24 IRCUIT IAGRAM 15.3 ........................
-
Page 5: General Description
1 GENERAL DESCRIPTION The Emtron DX-3 Linear Amplifier is a 3000 watt average output power, for the 160m through 10m amateur bands (9 bands), housed in a desk-top cabinet with self-contained power supply and cooling system. -
Page 6: Internal View
1.1 DX-3 – Internal View The main components of a DX-3 amplifier are shown in the picture below. BLOWER Temperature Sensor RF SENSOR RF CHOKE SOFT START CONTROL Tetrode GU78B BOARD (4CX3000) TERMINAL BLOCK, SOFT START HIGH VOLTAGE POWER SUPPLY... -
Page 7: Technical Specifications
OPERATIONAL PROTECTION • Overdrive protection: Should the DX-3 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. -
Page 8: Unpacking
Make sure the transformer is wired for the nominal mains voltage in your area. See 7.4 Two people are needed to install the transformer. The best is to put the DX-3 on a flat, smooth surface such as a bench or a table top, covered by a small carpet of a folded blanket, so that it can be moved by sliding it on the table. -
Page 9: Installation Environment
5.1 Power / Earth connections A wing-nut Earth connection is provided at the rear of DX-3. 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... -
Page 10: Rf Connections
ALC input jack. A shielded patch lead with an appropriate connector at one end and a male RCA connector for the DX-3 at the other end is required. Check the specifications of your transceiver for a suitable connection. -
Page 11: Displays
ON Air - single LED, green. When pressing PTT, this LED turns on (while in OPERATE) READY - single LED, yellow. Turns on at the end of warm-up period, when the mains power to DX-3 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. -
Page 12: Electrical Connections
Before connecting any power to the amplifier, make a good Earth connection to the screw with wing nut at the rear of DX-3. Make sure the POWER switch on the front panel is in the OFF position. Then plug the power cable into the power outlet. -
Page 13: Description
8 DX-3 DESCRIPTION 8.1 RF Section The RF section occupies the right hand side of the DX-3 (looking from the top - front). See picture in 1.1. RF Switch and tuned circuits At the front of the amplifier are two variable capacitors, for plate and load tuning. A 9-position ceramic switch is employed for the 9 operating bands. -
Page 14: Mains Transformer
5 seconds, avoiding the high inrush current typical for such big loads. 8.5 Sensor module A small metal box positioned at the output of the DX-3. It detects the forward and reverse power, for measurement and display. - Page 15 2 seconds. It ensures a clean signal, making it virtually impossible to overdrive the DX-3 • SWR detector and timer - switches the amplifier to bypass mode for about 3 seconds when high SWR is detected.
-
Page 16: Powering Up
Switch now the mains power ON (The power switch to ON position). The "soft start" system will take about 5 seconds to fully turn the power on. SWR light will turn on briefly, then off. Wait for the DX-3 to warm up, until the READY light turns on. -
Page 17: Final Tuning
• Repeat the above steps, while gradually increasing the input drive power, until the overdrive indicator just starts turning on. Now the DX-3 is tuned for operation at full power on that particular operating frequency. NOTES: 1. The maximum power is obtained from a DX-3 when:... -
Page 18: Potential Problems During Tuning
• If the SWR protection cuts in - it is likely that your antenna is not a good 50 ohm match at the operating frequency. In principle, the SWR protection level in DX-3 is adjustable, but it is far preferable for you to fix your antenna. -
Page 19: Using Your Dx-3
400 microamperes of grid current. See the Appendix 2 and the Troubleshooting section for oscilloscope displays showing examples of a two tone generator driving the DX-3 in linear mode, and an overdrive situation, when a DX-3 with the overdrive protection disabled is being overdriven by the two-tone generator. -
Page 20: Switching The Power Off
If it is still not working, unplug the power cord from the mains, then remove the fuses from the fuse holders on the rear, panel of DX-3 and check them with an ohmmeter. If a fuse is blown, replace it with a fuse of the same type and try again. -
Page 21: Over-Current Cut-Off
The screen current limiting in DX-3 is so efficient, that the tube is fully protected even in such a situation and test bench DX-3's have been extensively run with no plate voltage and maximum screen voltage, with no effect on the tube. -
Page 22: Glossary
14 GLOSSARY Alternating Current Automatic Level Control Amplitude Modulation BALUN Balanced to Unbalanced Transformer Bayonet Neil-Concelman Connector decibel Continuous Wave Direct Current Electronic Bias Switch Frequency Modulation High Frequency High Voltage International Electro-technical Comission Inter-Modulation Distortion Light Emitting Diode Peak Envelope Power Radio Frequency RTTY Radio Tele Type... -
Page 23: Appendix 1: Schematic Diagrams
15 APPENDIX 1: SCHEMATIC DIAGRAMS 15.1 DX-3 Block Diagram POWER SUPPLY DISPLAY MODULE MODULE (See Schematic) & METERS (See Schematic) O’DRIVE FAULT ON AIR H.V. H.V. READY Protec RF / TUBE Protect MODULE -Eg1 (See Schematic) SENSOR CONTROL BOARD MODULE... -
Page 24: Circuit Diagram - High Voltage Power Supply
15.2 Circuit Diagram – HIGH VOLTAGE POWER SUPPLY NOTE: Two modules used in parallel 470uF/450V 6A100 6A100 1000pF 1000pF 330k 6A100 6A100 1000pF 1000pF 470uF/450V 330k 6A100 6A100 1000pF 1000pF 470uF/450V 330k 6A100 6A100 1000pF 1000pF 470uF/450V 330k 6A100 6A100 1000pF 1000pF 470uF/450V... -
Page 25: Control Board And Adjustment Points
15.3 Control Board and Adjustment Points COMPONENT SIDE VIEW The drawing below shows all the connections to the control board and the adjustment points. Unless you know very well what you are doing and you have a reason to do it, do not modify any adjustment! VIOLET PNK/BLK Sensitivity... -
Page 26: Circuit Diagram - Ac Input And Wiring Diagram - Standard
15.4 Circuit Diagram – AC INPUT AND WIRING DIAGRAM – Standard... -
Page 27: Circuit Diagram - Ac Input And Wiring Diagram - U.s. Version
15.5 Circuit Diagram – AC INPUT AND WIRING DIAGRAM – U.S. Version... -
Page 28: Circuit Diagram - Soft Start (200 To 240 V Operation)
15.6 Circuit Diagram – SOFT START (200 TO 240 V OPERATION) -
Page 29: Circuit Diagram - Qsk
Jenings TJ1A-26S Or P1D-1V RF OUT 10uF/50V 1N4004 (TO RF SENSOR) RF DECK IN 33/2W RF DECK OUT RF IN (SO239) E M T R O N Title QSKv3 DX-3 Size Document Number QSKV3DX3 Date: Monday , January 07, 2002 Sheet... -
Page 30: Circuit Diagram - Rf Module
15.8 Circuit Diagram – RF MODULE NOTE: R1 changed to 680 ohm R.F. OUT MODULE (Simplified Diagram) PLATE VOLTAGE PLATE CHOKE 2200pF 500pF 1100pF 1000pF/6kV 1000pF/6kV 1000pF/6kV 1000pF/6kV 700uH F.O. PROTECTION BOARD A106 A106 A106 A106 A106 GU78B 10nF/1kV 1N4148 SCREEN 2.2nF 1N4148... - Page 31 X3-14 100uF X3-1 X3-12 X3-4 VOLT LM3914 X3-11 LM3914 LM3914 LM3914 FORWARD POW ER X3-8 X3-9 47uF Ig2- Ig2+ LM3914 LM3914 2.nF X3-2 LM3914 LM3914 47uF X3-6 2.2nF SWR/FLT X3-3 X3-15 FAULT 2.2nF X3-13 X3-7 2.2nF LM3914 X3-16 REFLECTED POW ER E M T R O N X3-10 X3-5...
-
Page 32: Circuit Diagram - Control Board
15.9 Circuit Diagram – CONTROL BOARD... -
Page 33: Control Board - Component Legend (Silkscreen Top)
15.10 CONTROL BOARD – Component Legend (Silkscreen TOP) EBS OFF... -
Page 34: Control Board - Solder Side Track Work
Control Board – Solder Side Track work C O P P E R L A Y E R S O L D E R S I D E... -
Page 35: Appendix 2: Waveforms
No “Hot switching”: The output relay (Top trace) switches first, then the RF drive is applied (Bottom trace) 16.2 Linearity a=-1674mV,b=1958mV 21Apr2003 18:36 Fig. 5 Sample of linearity curve obtained on a DX-3 at 4000 W PEP output, by using a two-tone generator and a PC oscilloscope in XY mode. -
Page 36: Appendix 3: Adjustments
17 APPENDIX 3: ADJUSTMENTS ADJUSTMENTS TO EMTRON “DX” AMPLIFIERS CAUTION Most of the following adjustments require the amplifier to be open and powered up. This also implies defeating the mains interlock safety switch, which is extremely dangerous since high voltage / high power DC and AC and RF voltages are exposed. -
Page 37: Swr Protection Adjustment
If the protection wasn’t activated immediately, increase the sensitivity (Rotate clockwise for DX-1, DX-2 and anti-clockwise for DX-2SP and DX-3, which have horizontally installed boards – access on the component side). Repeat applying power for a short time only, until the protection is triggered. -
Page 38: Screen Voltage Adjustment (Adjustment: Pot2, Marked Screen)
The screen voltage can be measured on the pin marked EG2 on the control board (close to the jumper EBS, this pin has a blue wire connected to it; in DX-3 it is easier to measure on either side of R18). The amplifier must be READY and on OPR for the screen voltage to be present. - Page 39 BIAS SCREEN VOLTAGE SENSITIVITY SCREEN EBS OFF CURRENT LIMIT EBS ON PROTECTION Figure 6...
-
Page 40: Display Board Adjustments
PLATE CURRENT PROTECTION EBS OFF SCREEN EBS ON CURRENT LIMIT SENSITIVITY SWR1 SWR4 SCREEN BIAS VOLTAGE PRE-BIAS (Ip0) Figure 7 17.2 DISPLAY BOARD ADJUSTMENTS The display board is pre-adjusted during testing. However, when installed in the amplifier, most adjustments need to be fine-tuned. Remove the front panel glass to gain access to adjustments. -
Page 41: Forward Power (Adjustment: Vr1, Marked: Rf F)
On 20m, operate the amplifier at the full nominal power, as indicated by an external power meter: 750W for DX-1 1500W for DX-2 2000W for DX-2SP 3000W for DX-3 Adjust potentiometer “RF F” for correct display indication 17.2.5 SCREEN CURRENT (Adjustment: VR6, marked IG2+, VR5, marked IG2-) ig2-: put VR5 in the middle position ig2+: connect a mA meter in series with the screen supply, between the control board pin EG2 and the blue screen wire. -
Page 42: Rf Sensor Adjustment
17.3 RF SENSOR ADJUSTMENT The amplifier is switched off for this adjustment. Check if adjustment is required as per following procedure, before opening the sensor. Unsolder and remove the metal cover. Connect a transceiver to the input and a dummy load to the output of the amplifier. Connect a voltmeter to pin SW1 or SW2 on the control board (with yellow/black wires).
Need help?
Do you have a question about the DX-3 and is the answer not in the manual?
Questions and answers