5
DX-1d LINEAR AMPLIFIER
Serial No
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OPERATING MANUAL
April 2003
CAUTION
1 GENERAL DESCRIPTION
The Emtron DX-1d Linear Amplifier is a 750 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.
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
protection systems and indefinite duty cycle (continuous commercial service).
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.
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.
