Acom 1011 User manual

HF LINEAR AMPLIFIER
ACOM OOD
Bul. Nikola Mushanov 151
1330 Soa, Bulgaria
phone: [phone]
fax: [phone]
e-mail: [email protected]
www.acom-bg.com
September 2011
Printed in Bulgaria

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Table of Contents
1. GENERAL INFORMATION ..................................3
1-1. Introduction and Description .....................................3
1-2. Owner Assistance ..............................................3
1-3. Equipment Supplied ............................................3
1-4. Features ..................................................... 3
1-5. Safety Considerations, Explicit Definitions ...........................4
2. INSTALLATION ............................................5
2-1. Unpacking and Initial Inspection ................................... 5
2-2. Line Voltage Selection ...........................................6
2-3. Amplifier Location Selection ......................................6
2-4. Connections ..................................................6
3. POWER ON, CONTROLS AND INDICATORS ...................8
4. OPERATION..............................................10
4-1. Turning ON and OFF ..........................................10
4-2. Changing Operate and Standby Modes.............................10
4-3. RTTY Mode..................................................11
4-4. Antenna change...............................................11
4-5. Tuning ......................................................11
4-6. The Auto-Protection System .................................... 13
5. MAINTENANCE...........................................14
5-1. Cleaning ....................................................14
5-2. Fuses Replacement ............................................14
5-3. Tubes Replacement ............................................15
5-4. Simplified Schematic Diagram....................................15
5-5. Service Functions ............................................. 16
6. SPECIFICATIONS .........................................16
6-1. Parameters ..................................................16
6-2. Functions....................................................17
6-3. Storage and Shipment ..........................................18

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We express our thanks to
Jim Talens, N3JT for his editorship and Ron Stone, GW3YDX
for his comments and suggestions

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1. GENERAL INFORMATION
Congratulations on purchasing one of the finest HF amplifiers in the world today. ACOM is pleased
that you have chosen one of our products, and we will endeavor to provide you with the information
and support you need to enjoy your purchase for many years. We urge you to read all of the following
materials before you embark on operating your new amplifier.
1-1. Introduction and Description
This manual explains the installation, operation, and maintenance of the ACOM1011 HF linear
amplifier.
The ACOM1011 is a self-contained linear amplifier that covers all amateur bands, from 1.8 through
29.7 MHz. It provides over 700 W PEP of output power (or 500 W in continuous-duty operation) with
less than 60 W of drive. The amplifier is designed to tolerate VSWR levels of up to 3:1 throughout its
operating range, and tuning is simplified by ACOM’s exclusive True Resistance Indicator (TRI). Also,
a built-in antenna selector switch with two outputs is included to provide instant choice of antennas.
Importantly, a variety of system parameters are continuously monitored and available to the operator
to assure safe and efficient amplifier operation.
1-2. Owner Assistance
If technical or operating assistance is needed, your local dealer should be contacted first. In the unlikely
event you need further information, you may get in touch with ACOM by facsimile, telephone, email or
standard mail. Fax: + 359 2 920 9656; telephone: + 359 2 920 9655; e-mail: [email protected];
standard mail: ACOM, Bul. N. Mushanov 151, 1330 Sofia, Bulgaria.
1-3. Equipment Supplied
The ACOM1011 amplifier and this manual are shipped in a cardboard carton.
1-4. Features
Easy operation. The plate-load True Resistance Indicator (TRI) is an ACOM innovation that provides
quick and precise tuning, typically in less than 10 seconds. The auto-operate function will return the
amplifier to the OPERATE mode automatically after each protection trip, saving time and avoiding manual
switching.
No tuner needed. No external antenna tuner is required as long as the antenna VSWR is 3:1 or lower.
The amplifier will perform the functions of an antenna tuner, enabling you to change antennas faster and
use them over wide frequency ranges.
A durable amplifier. This amplifier is both user-friendly and self-monitoring. It is designed to safely
withstand up to 240 W of reflected power, up to 100 milliseconds of drive spikes (RF “tails” after a PTT
or KEY release), and even operator tuning errors. It is also capable of operating at more than half its
designed output power at only 75% of nominal line (mains) voltage. Because it can tolerate deep voltage
drops (down to zero for 10 milliseconds) and 15% line voltage spikes, it is particularly suited for use in
portable environments, such as field days and DXpeditions.
LED bar-graph display. The upper LED bar-graph always reads peak forward power (except for the
service functions) while the lower LED bar-graph is for the reflected power. LED warning indicators are
provided for abnormal conditions of grid 1, grid 2, and plate parameters.

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Antenna selection. Two antenna outputs are selectable on the front panel of the amplifier.
Efficient tuning. Antenna matching can be achieved in less than 10 seconds and at a quarter of nominal
output power, which produces lower risk of interference to other stations and greater safety to the
amplifier components.
Transceiver-independent. The amplifier operates without special signaling from the transceiver; it
needs only “ground on TX” and 60 W RF drive power to operate at full output power.
Input matching. Broadband input matching circuitry offers excellent loading characteristics for the
driving transceiver, from 1.8MHz to 30MHz.
Reliable tubes. Two 4CX250B (7203) ceramic-metal tetrodes with a total plate dissipation of 500W
(forced air cooling, grid-driven) are used for maximum efficiency.
Short warm-up period. Only 30 seconds warmup period is required.
Permanent monitoring and protection of the plate and grid currents. The Bias Optimizer minimizes
heat dissipated by the tubes, assuring tubes longevity.
High voltage protection. Design of the high-voltage power supply eliminates the danger of turn-on
transients affecting sensitive devices connected to the same line (mains) circuit. Moreover, the amplifier can
be configured to accommodate any of 8 nominal line voltages between 100 and 240 V, 50 or 60 Hz.
Band inclusion. The amplifier can be shipped with 10 and 12-meter capability disabled as required by
the Federal Communications Commission (FCC), for United States users. Contact your dealer about
enabling those bands.
1-5. Safety Considerations, Explicit Definitions
The ACOM1011 HF Linear Amplifier is a Safety Class I unit. The grounding lead (yellow with 2 green
stripes) of the power cable and the ground stud on the rear panel of the amplifier (marked GND) must
be connected to the station’s grounding system for safe operation. The amplifier is designed to meet
international safety standards and complies with CE safety and electromagnetic compatibility requirements,
as well as FCC regulations. This operating manual contains an assortment of precautions and warnings
that MUST BE FOLLOWED BY THE USER to ensure safe operation of the amplifier.
The safety definitions below apply to this operating manual:
A WARNING is associated with a procedure that, if not properly performed, could result in a fire hazard
or electric shock, with resulting injury or death to the user.
A CAUTION is associated with a procedure that, if not properly performed, could result in damage to
the amplifier or other equipment.
A NOTE is associated with a procedure that, if not properly performed, could result in inconvenience
or physical injury to the user.

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WARNING HIGH VOLTAGE!
The amplifier works with voltages up to 3000 V dc, which are potentially
LETHAL! You must unplug the amplifier from the line (mains) wall outlet
and WAIT AT LEAST 30 minutes before removing the cover of the amplifier.
Do not touch any part inside while the amplifier is open because dangerous
voltages may remain present.
WARNING HIGH VOLTAGE!
NEVER ALLOW ANYONE, ESPECIALLY CHILDREN, to push anything
into the case holes or to otherwise touch the amplifier or its connecting
cables. There is grave danger of fatal electrical shock. NEVER TOUCH AN
ANTENNA during transmission as this may result in an electric shock or
burns. NEVER EXPOSE the amplifier to rain, snow or any liquids. AVOID
placing the amplifier in excessively dusty environments. DO NOT OBSTRUCT
AIR INTAKE (bottom) or EXHAUST (top cover) areas of the amplifier. Keep
a minimum distance of 50cm (20 inches) clear of the air exhaust opening.
WARNING
Do not undertake or perform any repair or adjustment of your amplifier
yourself, including any attempt to change hardware or firmware. Doing so
creates a potentially fatal shock hazard and may damage the amplifier or
equipment connected to it. ACOM is not responsible for any such personal
injury or equipment damage, whether caused by accident or as a result of
good faith efforts at repair or adjustment.
CAUTION
To avoid damage to the amplifier not covered by ACOM’s warranty, the user is
expected to read and comply with the installation instructions contained in Section 2
of this operating manual. If there are any doubts or questions concerning installation,
operation or safety of the amplifier, the user should contact ACOM.
2. INSTALLATION
2-1. Unpacking and Initial Inspection
NOTE
The first step to installation is to fully read this manual. Then, carefully inspect the
shipping cartons for any physical damage. ACOM ships amplifiers in highly protected
containers, but it cannot assure that mistreatment by shippers will not occur. If there
is any such damage, notify your ACOM dealer immediately. Failure to do so may
invalidate your warranty. In any case, be sure to keep all packing materials for possible
future amplifier shipment.

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2-2. Line Voltage Selection
CAUTION
To avoid damage to your amplifier and to maintain your warranty coverage, be
certain that the amplifier line (mains) voltage setting corresponds to your nominal
line (mains) voltage.
Normally, the amplifier is delivered with the Voltage Selector set for a nominal line voltage of 240 V. If
your line voltage is not 240 V, you must contact your dealer for instructions on how to change the voltage
selector inside the amplifier. The only exception to this is if the unit has been custom ordered, in which
case the voltage selection will be noted in the Table of Individual Data (Table 2-1, below).
AMP s/n
Left tube s/n
Right tube s/n
Voltage Selector VAC
Table 2-1. ACOM 1011 Individual Data
2-3. Amplifier Location Selection
Locate the amplifier as close as possible to where it can be used conveniently. Access to the command
knobs and indicator’s area, as well as to the rear panel cabling, will be necessary.
No device that is sensitive to magnetic fields, including dynamic microphones, should be located adjacent
to the right side of the amplifier, where the power transformer is mounted. The amplifier should generally
be placed to the right of your transceiver. No temperature-sensitive devices should be located above
the air exhaust ports. This means the amplifier should not be located under a shelf or other structure
that could impede the free movement of air away from the amplifier.
DO NOT OBSTRUCT AIR INTAKE (bottom) and EXHAUST (top cover) areas of the amplifier. Keep a
minimum clear distance of 50cm (20 inches) above the exhaust opening.
2-4. Connections
Before applying line (mains) voltage to your amplifier, follow the steps listed below in the order they
are presented.
WARNING
Note that your grounding system may have to handle a current of more
than 15 Amperes. This requires an adequately sized and well-maintained
conductor of at least 4 mm2 (AWG 11 or SWG 13). If this is not the case
at your operating location, you should make the necessary changes using a
licensed electrician.

dab
FUSE 5x20
c
DANGER! HIGH VOLTAGE INSIDE !
FOLLOW INSTRUCTIONS PRECISELY
DISCONNECT AC POWER
BEFORE REMOVING COVER !
FCC ID:
MODEL: ACOM 1011
SERIAL NO.:
KEY IN GND
RF INPUT ANT 1 ANT 2
FUSES
100-120V: 10A
200-240V 6.3A
100-120 or 200-240 V
50-60 Hz 1200 VA
MADE IN BULGARIA
Fig. 2-1 Connections
a) Connect the station’s grounding system to the wing-nut ground stud of the amplifier (on the rear
panel, marked GND in Fig. 2-1).
b) Connect a suitable coaxial cable between the transceiver output to the amplifier (rear panel) RF
INPUT SO-239 connector, using PL-259 connector.
CAUTION
The coaxial cable from the amplifier’s output must be capable of handling the
amplifier’s output power safely, particularly on the 10-meter band. It is suggested
that, at a minimum, RG8X (including RG8MINI, RK50-4-11, RK50-4-13) or, even
better, RG213 (including RK50-7-11) coaxial cable be used.
c) Connect a suitable coaxial cable from the antenna to the appropriate amplifier output (on the rear
panel, marked ANT1 or ANT2), using a PL-259 plug.
d) Run a shielded cable from the “ground on transmit” socket or terminal on your transceiver to
the amplifier rear panel KEY-IN socket. The KEY-IN socket uses a standard RCA phono plug.
NOTE
Your amplifier will not work if KEY-IN is not connected properly.
Transceiver producers assign different names to their “ground on transmit” output terminals, e.g., TX-
GND, SEND, T/R-LINE, etc. Some transceivers may require that “ground on transmit” be implemented
by a software command, or by changing the setting of a switch on the rear panel or inside the transceiver.
Check your transceiver’s manual for more information on keying amplifiers.
e) Preparation of the wall outlet for the amplifier.
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WARNING
If your amplifier is only fitted with one line (mains) fuse, it is suitable for the
European Community ONLY. Your dealer will check that your amplifier is
correctly fused before it is shipped to you, based upon your indicated location.
Customers should check with a qualified electrician if the amplifier is to be
used outside the country in which it was purchased.
Due to different line (mains) standards in different countries, the dealer will provide the correct Safety
Class I plug for your location. The ground lead of the power cable is colored yellow with two green
stripes. If you have any doubts about the correct way to connect these wires, consult your dealer.
WARNING
Before connecting the amplifier to your line (mains) supply, be sure that the
line (mains) supply is correctly wired and is capable of providing the required
current, i.e., up to 5 A from 240 V and 10 A from 120 V. As discussed earlier,
it is very important that the ground lead is adequately sized and properly
connected.
The Power Switch on the front panel must be in the OFF position; only then should you insert the
amplifier’s line (mains) plug into the appropriate wall outlet. At this time the amplifier remains switched
off.
3. POWER ON, CONTROLS AND INDICATORS
CAUTION
Do not turn the amplifier on for at least 2 hours after unpacking it and locating in its
operating location. Pay particular attention whenever the amplifier is moved from
a very cold place to a very warm one because unseen condensation may develop,
and this could result in damage to the high voltage circuits of the amplifier. Under
these circumstances, do not turn the amplifier on for at least 4 hours. A similar effect
could occur following rapid warming of the location, such as winter use of a powerful
electric heater.
CAUTION
To avoid damage that may not be covered by the amplifier warranty, carefully check
that the voltage for which the amplifier is set corresponds to your nominal line (mains)
voltage. See Section 2-2 and Table 2-1.
After following all instructions in Section 2, you may now turn ON the main power switch on the front
panel (Fig. 3-1). The green LED indicator above the switch will illuminate:

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ON
TX
OPER RTTY A2A1
RFL
240 G1 G2 IP F 120
30
FWD
80040020050 600
LOAD
0
10
20
30
40 60
70
80
90
100
50
TUNE
0
10
20
30
40 60
70
80
90
100
50
BAND
1.8
3.5
7
10
14
18-21
24-28
Fig. 3-1 ACOM1011 Display and Control
Note that the upper LED bar-graph always reads peak forward power, except for the service functions
(Section 5-5). The 800 W-scale resolution is 50 W. Note also that levels below 50 W may be not
detected.
The lower LED bar-graph will indicate reflected power up to 240 W. The scale resolution is 30 W.
The OPER button alternatively switches between the operate and standby modes once the amplifier
has completed its 30-second warm-up period. See Section 4-2.
The RTTY button reduces the output power of the amplifier to 500 W. See Section 4-3.
The button labeled A1-A2 (Section 4-4) changes the antenna output to either antenna 1 or antenna 2,
according to the operator’s choice. It is the operator’s responsibility to connect suitable antennas to
the ANT1 and ANT2 connectors on the rear panel of the amplifier.
The red TX LED illuminates whenever the KEY-IN input is keyed (closed to ground), i.e., when the
transceiver goes into the transmit mode. See Section 2-4(d).
The BAND knob controls the band switch, and LOAD and TUNE are used to adjust their respective
variable air capacitors in the amplifier’s output circuit. The settings of these three controls must be changed
at each band change as well as when an antenna is changed. The three LED indicators located above
the knob LOAD are called the “TRI tuning indicator” and they are used to achieve antenna impedance
matching during a re-tune procedure. Please see Section 4-5 for a discussion of the tuning procedure.
CAUTION
To avoid damage not covered by the amplifier’s warranty, do not turn the BAND
switch while transmitting. Switching while transmitting is called “hot switching” and
it will cause irreparable damage to the band switch.
There are three warning LED indicators and one fault LED indicator located in the bar-graphs area.
The following describe the error conditions and the correct responses (except for the service functions
- Section 5-5):
- G1 – when illuminated, a control-grid overload condition exists; reduce the drive power for safe
operation;