Acom 1010 User Manual

User's Manual | ACOM 1010 | HF Linear Amplifier
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| S e c t i o n MAINTENANCE
July 2021
5.5. Simplified Schematic Diagram
Please, see Figure 5-1 Simplified Schematic Diagram.
The 4CX800A (GU74B) Svetlana high performance ceramic-metal tetrode (V1) with plate dissipation of
800 W is grid-driven. The input signal from the RF INPUT jack is passed through a broadband input
matching circuit, which consists of components on the INPUT PCB and includes the drive-power swamping
resistor Rsw. This circuit tunes out the input capacitance of the tube. The swamping resistor Rsw is a
termination load for the matching circuit and can dissipate up to 80W of RF drive power. It also eliminates
any tendency toward oscillation by the tube, ensuring excellent RF stability of the amplifier.
The cathode resistor Rc creates DC and RF negative feedback, thus stabilizing gain and equalizing frequency
response. The combination Lp1-Rp1 in the plate circuit is a VHF/UHF parasitic suppressor. DC plate voltage
is fed through chokes RFC1-RFC2 and the capacitor Cb3 blocks it from the output. The output tank,
comprised of LP1, LP2, LL, CP1-CP3, and CL1-CL4, forms a classic Pi-L network and suppresses harmonic
frequency emissions. This circuit is switched and tuned by S1A-S1C and the air variable capacitors CP1, 2
and CL1, 2. The output signal is fed through the antenna relays K1 and K2 in the WATTMETER PCB. The
WATTMETER PCB also includes a high-pass filter for frequencies below 100 kHz, and it prevents the plate
supply from reaching the antenna.
The plate RF voltage is monitored through the capacitor Ca and together with the RF WATTMETER is the main
source of information for the control circuit of the amplifier in evaluating tuning quality. The control circuit is
based on the ATMEGA-8L micro-controller from Atmel. All voltages are delivered from the line (MAINS) and HV
PCBs. The currents of the control grid, screen grid, and the plate, as well as the reflected power and tuning
quality, etc. are continuously monitored by the micro-controller. Many software-derived protections are based
on this information.
Detailed electrical schematic diagrams are available from ACOM or from your dealer on
request.

Acom 1010 Specifications

General

Complies with CE safety and electromagnetic compatibility requirements, as well as FCC regulations	Yes
Power Output	1000 W PEP
Modes	SSB, CW, RTTY, AM, FM
Power Supply	200-240VAC or 100-120VAC, 50-60Hz, single phase.
Cooling	Forced air
Harmonic Output	-50 dB
Input Impedance	50 Ohms
Output Impedance	50 Ohms
Tube	4CX800A