Acom 1006 User manual

6 m LINEAR AMPLIFIER
OPERATING MANUAL

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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 ............................................................................................................................... 5
2-3. Amplifier Location Selection..................................................................................................................... 5
2-4. Connections................................................................................................................................................ 6
2-5. Installation of External Fan ....................................................................................................................... 8
3. POWER ON, CONTROLS AND INDICATORS ................................................................ 8
4. OPERATION..................................................................................................................... 9
4-1. Turning ON and OFF ................................................................................................................................ 10
4-2. Changing Operate and Standby Modes ................................................................................................. 10
4-3. Tuning........................................................................................................................................................ 10
4-4. "ON LINE" Information Screens and Control Functions...................................................................... 12
4-5. Auto-Protection System .......................................................................................................................... 13
5. "OFF LINE" OPERATION.............................................................................................. 13
5-1. Contrast and Back-lighting control ........................................................................................................ 13
5-2. Auto-Operate enabling and disabling .................................................................................................... 13
5-3. Reading Auto-protection Signatures ..................................................................................................... 14
6. MAINTENANCE ............................................................................................................. 14

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6-1. Cleaning .................................................................................................................................................... 14
6-2. Fuses Replacement.................................................................................................................................. 14
6-3. Tube Replacement ................................................................................................................................... 15
6-4. The ACOM1006 Simplified Schematic Diagram .................................................................................... 15
6-5. Troubleshooting ....................................................................................................................................... 16
7. SPECIFICATIONS.......................................................................................................... 18
7-1. Parameters................................................................................................................................................ 18
7-2. Functions .................................................................................................................................................. 18
7-3. Storage and Shipment ............................................................................................................................. 19

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1. GENERAL INFORMATION
1-1. Introduction and Description
This manual explains the installаtion, operation, and maintenance of the ACOM1006 six meters linear
amplifier.
The ACOM1006 is a complete and self-contained linear amplifier that covers the amateur band 50-54MHz
and provides over 1000W output power with less than 60W exciter drive. Antenna VSWR up to 3:1 is
acceptable at full power. Tuning is substantially simplified by a plate-load True Resistance Indicator (TRI) and
by an automatically-controlled input attenuator. Operating parameters are displayed by a multi-functional
back-lighted Liquid Crystal Display. Full break- in (QSK) is standard for transmit/receive switching.
1-2. Owner Assistance
If assistance is needed, you should contact your local dealer first. If you still have an issue you need to
discuss with one of ACOM’s specialists, the contact information is as follows:
•e-mail: <[email protected]>;
•tel: + 359 2 920 96 55, + 359 2 920 97 80, + 359 2 920 97 81;
•fax: + 359 2 920 96 56;
•mail: ACOM OOD, 151, Nikola Mushanov, blvd., 1330 Sofia, Bulgaria.
1-3. Equipment Supplied
The ACOM1006 amplifier and this manual are shipped in a cardboard carton.
1-4. Features
•Based on the well known ACOM1000 amplifier but optimized for six meters operation.
•Easy to operate. The TRI is a powerful tuning aid which, together with the automatically controlled input
attenuator, helps the operator more quickly and precisely match antennas (5-10 seconds typically). The
auto-operate function (when you have activated it) maintains the amplifier in operate mode for you, thus
saving manual operations and time.
•No heavy outboard antenna tuners required for antenna VSWR up to 3:1. Your amplifier will perform the
functions of an antenna tuner, thus enabling you to change antennas faster and use them over a wider
frequency range (saving tuning time).
•An amplifier that is both user-friendly, and that looks after itself. It is designed to safely withstand up to
300W reflected power, up to 100 milliseconds duration of drive spikes, drive RF "tails" after a PTT or KEY
release, operator's inadvertent tuning errors etc. It would also not cease to function with a "soft" AC
power line and would deliver more than half power at only 75% of nominal mains voltage. It would
withstand up to 10 milliseconds (down to zero) voltage drops, and up to +15% line voltage spikes, which
is important particularly when used at field days, DX-peditions, and other portable events.
•LCD comment display. All amplifier status indications are explained via detailed text displayed on the dot-
matrix back-lighted liquid crystal display (LCD). The upper line strip on the LCD always reads directly
peak forward power. LED indicators are provided for conditions of operate, attenuation-on, and ON/OFF.
•Easy maintenance. Signatures of the amplifier internal status are stored in a nonvolatile memory for 7
most recent auto protection trips. This information can be forwarded to your dealer for diagnostics. Using
an EXCEL APPLICATION (available from ACOM or your dealer free of charge) and a PC you can decode
the signatures by yourself, too.
•Less noise in the room: the input bypassing and the vacuum antenna relays are virtually silent even in
QSK CW mode due to their special mounting.

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•Less QRM and improved Electro-Magnetic Compatibility during tuning. Antenna matching can be
achieved in less than 10 seconds at a quarter of nominal output power.
•Operates without special signals from the transceiver - "ground on TX" and 60W RF drive power are
sufficient.
•Uses a single 4CX800A (GU74B) Svetlana high-performance ceramic-metal tetrode with plate dissipation
of 800W (forced air cooling, grid-driven).
•Permanent monitoring and protection of plate and grid voltages and currents, as well as of the exhaust air
temperature. The Bias Optimizer decreases the heat dissipated from the tube, and there is automatic
protection against overheating in accordance with the specifications of the tube producer.
•An output RF-Arc protection is employed. It safeguards the amplifier, antenna, antenna selector, and
tuner against severe damage in case of possible breakdown.
•Inrush current protection of the HV power supply, which eliminates the danger of affecting sensitive
devices, connected to the same power line (important when used portable). The amplifier can be
configured for 8 different nominal mains voltages: 100, 110, 120, 200, 210, 220, 230, and 240VAC, 50 or
60Hz.
•Continuous measuring and/or selectable monitoring of 12 most important parameters of the amplifier,
exciter and antennas via LCD.
1-5. Safety Considerations, Explicit Definitions
The ACOM1006 six meters Linear Amplifier is a Safety Class 1 unit. The third conductor of its mains cable
(which is colored yellow with two green stripes) and the grounding 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 information, precautions, and indications for cautions and warnings which
must be followed by the user to ensure safe operation and to keep the ACOM1006 in safe operating
condition.
PRECAUTIONS:
The EXPLICIT DEFINITIONS described below apply to this operating manual:
W A R N I N G notes call attention to a procedure which, if not correctly performed, could result in personal
injury, fire hazard or electric shock.
C A U T I O N notes call attention to a procedure which, if not correctly performed, could result in
equipment damage, not only in the amplifier.
N O T E notes call attention to a procedure which, if not correctly performed, could result in inconvenience.
W A R N I N G HIGH VOLTAGE!
The amplifier works with high voltages up to 3000V, which are LETHAL! Also, for your safety, pull the
amplifier power plug out of the mains wall outlet and WAIT AT LEAST 30 minutes EACH TIME BEFORE you
remove the cover of the amplifier. Do not touch any part inside because some residual voltages may still be
present.
W A R N I N G HIGH VOLTAGE!
NEVER ALLOW ANYONE, ESPECIALLY CHILDREN,
to push anything into holes in the case - this will cause electric shock. NEVER TOUCH AN ANTENNA during
transmission - this may result in an electric shock or burn. NEVER EXPOSE the amplifier to rain, snow or any

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liquids. AVOID placing the amplifier in excessively dusty environments or in direct sunlight. DO NOT
OBSTRUCT AIR INTAKE (rear panel) and EXHAUST (top cover) areas of the amplifier. Keep a minimum
distance of 10cm (4 inches) to the intake and 50cm (20 inches) to the exhaust.
W A R N I N G
Do not undertake on your own repairs or changes in hardware or software of the amplifier. Otherwise you
may endanger your or other's health and life or damage the amplifier and the equipment connected with it,
not covered by warranty. The manufacturer is not liable for another's actions and responsibility shall be
assumed by the doer.
C A U T I O N
Тo avoid damage (not covered under warranty), please read the Section 2 (Installation) of this operating manual
carefully. If you have any doubts about the installation, operation or safety of the amplifier please consult your dealer.
2. INSTALLATION
2-1. Unpacking and Initial Inspection
N O T E
Before you start to install the amplifier, thoroughly read this manual. First, carefully inspect the cardboard
carton and its contents for physical damage. If damage is noticed, notify your dealer immediately. Delay may
infringe carrier's warranty conditions. Keep all packing for possible future transportation!
2-2. Line Voltage Selection
C A U T I O N
To avoid damage (not covered under warranty), check carefully if the voltage for which the amplifier is set
corresponds to your mains nominal voltage.
When supplied, normally the amplifier is set for a nominal mains voltage of 240V. There might be exceptions
in cases of special delivery and then the voltage set is noted in the Table of Individual Data (Table 2-1).
AMP s/n
Tube s/n
Voltage Selector VAC
Table 2-1. The ACOM 1006 Individual Data
If your mains has a different nominal voltage, it will be necessary for you to contact your dealer. Means is
provided in the amplifier to reconnect it for 100, 110, 120, 200, 210, 220, 230, and 240 VAC nominal voltage.
2-3. Amplifier Location Selection
C A U T I O N
The weight of the unit is about 22kg, which should preferably be handled by two persons.
Position the amplifier near the place where it will be used. You'll need an easy access to the command knobs
and indicator area, as well as to the rear panel cabling.

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No magnetic-field sensitive devices should be located next to the right side of the amplifier as its power
transformer is located there. It's best to position it to the right of your transceiver. No temperature sensitive
devices should be located above the exhaust hot air area, so don't place it under a shelf. You may prefer to
utilize the bottom scales of both variable capacitor knobs (TUNE and LOAD) if you install it on a shelf. DO
NOT OBSTRUCT the AIR INTAKE (rear panel) and EXHAUST (top cover) areas of the amplifier. Keep a
minimum distance of 10cm (4 inches) off the intake and 50cm (20 inches) off the exhaust.
2-4. Connections
Connection to your station must be accomplished in the order described below, before you apply mains
voltage to the amplifier.
W A R N I N G
Note that the grounding system may have to withstand currents over 20A with insignificant voltage drop on it.
Therefore, it may be necessary to improve it considerably, i.e. to become less resistive, with heavier wires
and lower-resistive ground path. The grounding wires should be at least 8sq.mm (AWG 8 or SWG 10).
a) First, connect the ground stud of the amplifier (on the rear panel, marked GND) to the station's grounding
system (Fig.2-1).
b) Connect a coaxial cable with a PL-259 plug from the transceiver output to the amplifier rear panel RF
INPUT socket.
C A U T I O N
If this is the first time you will use a power amplifier in your station, pay attention to the coaxial cable type from
the amplifier's output. It must handle the increased power safely. We recommend, that you use RG213 or
better. Check the same for the antenna selector and the antenna itself.
c) Connect a coaxial cable from the amplifier output (on the rear panel, marked RF OUTPUT) with a PL-259
plug to the antenna selector or to the antenna.
d) Run a shielded cable terminated in a Phono (RCA) connector from the transceiver socket providing
"ground on transmit" to the amplifier rear panel KEY-IN socket.

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Transceiver producers give different names to this output and they are for instance TX-GND, SEND, T/R-
LINE, etc. Some transceivers require that "ground on transmit" is implemented via a software command, or by
changing the setting of a switch on the rear panel, or interior of the transceiver. Check your transceiver's
manual.
N O T E
Your amplifier will not work if KEY-IN is not connected properly.
This is the T/R control input of the antenna relay. When in operate, on this input appears a 12V DC signal
which must be held to the ground by the transceiver in order to activate the amplifier. This can be done via
either a relay contact or a semiconductor - transistor or integrated circuit - having a suitable polarity (positive
to ground). You should prefer a semiconductor output when available on your transceiver, since relay
contacts on some transceiver models are slow with respect to their RF output. You may otherwise get a "Hot
Switching Warning" message. In such a case, change to the semiconductor output.
The electrical specifications of the amplifier's KEY-IN input are:
- switching voltage (open circuit): 15V max, positive to ground;
- switching current (closed circuit): 15mA max;
- voltage drop or resistance of the control output @ 15mA (closed circuit): 1.5V/250 Ohm max.
e) The KEY-OUT socket on the rear panel provides an extra control signal from the amplifier to the
transceiver. It could be used to improve the transmit/receive switching safety.
If your transceiver has a suitable input that disables transmission, we recommend that you connect it with a
shielded cable terminated in a Phono (RCA) connector to the KEY-OUT socket of the amplifier. Transceiver
producers give different names to this input and they are for instance TX-INHIBIT, MUTE, LINEAR, etc.
Check your transceiver's manual or consult your dealer.
If your transceiver does not have such an input, don't worry - the amplifier contains an independent self
protection for the antenna relay. It looks after the T/R switching to be safe, regardless of taking or not
advantage of the KEY-OUT possibility, so the amplifier will function normally, and the KEY-OUT may remain
unused as well.
The output KEY-OUT of the amplifier is an open-drain circuit and it can hold to ground a positive DC signal.
During all the periods when the amplifier is ready to transmit, this line is following the "GND on TX" request in
order to enable transceiver transmission. When transmitting is not permissible (for instance, while the
antenna relay is in process of switching-over), this output opens and the transceiver would stop driving.
The electrical specifications of the amplifier's KEY-OUT output are:
- switching voltage (open circuit): up to +50V;
- switching current (closed circuit): up to 20mA;
- resistance @ 20mA (closed circuit): 120 Ohm max.
f) Preparation of wall outlet for the amplifier.
W A R N I N G
If your amplifier is only fitted with one mains fuse, it is suitable for 0-220...240 VAC electricity supplies ONLY
(these supplies are standard in the European Community). Your dealer will check that your amplifier is
correctly fused before it is shipped to you. Customers should check with a qualified electrician if the amplifier
is to be used outside the country in which it was purchased.
Due to the different standards in different countries, the mains plug is supplied and mounted by the dealer.
He will install on the mains cable a standard mains supply plug which meets the Safety Class 1 units
standard in your country. The grounding wire of the amplifier's power cord is colored yellow with two green
stripes and the blue and brown wires are active. When the amplifier is to be used with only one mains fuse, it
is connected in series with the brown wire, which must be the active. If you have any doubts about the correct
way of connecting the wires, consult your dealer.

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It is preferable that you use the wall outlet closest to the source. The installation wires should be at least
1.5sq.mm (AWG 15 or SWG 17) for 200-240 VAC and 2.5sq.mm (AWG 13 or SWG 15) for 100-120V AC.
Check if the respective fuses can handle current up to 10A for 200-240 VAC and 20A for 100-120VAC. Check
also whether the voltage corresponds to the voltage for which the amplifier is set (S.2-2). If you would
connect the amplifier to a new mains outlet, be sure that you check it, too.
Make sure the main Power Switch on the rear panel is in OFF position and then insert the amplifier's mains
plug into the prepared wall outlet. The amplifier remains switched off.
2-5. Installation of External Fan
This fan (Fig. 2-1) is not necessary in SSB and CW modes, nor in continuous carrier modes (RTTY, SSTV
etc.) with transmission times of maximum 15 minutes and a subsequent pause of 3 minutes or longer. For
higher duties or ambient temperatures the fan is recommended. The auxiliary fan (92x92mm) must be
brushless type, 2...5W/24VDC. It may be installed by your dealer or by the manufacturer on request.
3. POWER ON, CONTROLS AND INDICATORS
C A U T I O N
Do not turn the amplifier on for at least 2 hours after unpacking it in the room where it will be used. Pay
particular attention when you move it from a very cold into a very warm place since condensation is likely. A
similar effect can occur after a rapid warming of the operating room (for instance after switching on a powerful
heater in a cold room). In such a case, wait at least 4 hours. Any condensation appearance could result in
damage to the high-voltage circuits.
C A U T I O N
To avoid damage (not covered under warranty) carefully check that the voltage for which the amplifier is set
corresponds to your mains nominal voltage (see S.2-2 and table 2-1).
After following all instructions in S.2, you can turn ON the main power switch marked "LINE" on the rear panel
(Fig.2-1). The LED indicator above the red ON/OFF button (located on the front panel) must light red and a
black inscription "ACOM1006" will appear on the LCD (Fig.3-1):
Fig.3-1 ACOM1006 Display and Control
You'll note that the upper line of the LCD always shows directly peak forward power, even during standby and
"OFF LINE" operation. The full scale is 1200W with a resolution of 10W per bar. One division weight is 60W,
and figures are multiple to 300W. Note also that levels below 20W may be not detected.

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N O T E
If the characters on the LCD are dim or not readable, please follow the method of LCD contrast and back-
lighting adjustment described in S.5-1.
In this position (called "OFF LINE" hereafter) only the micro-controller is operational, while the amplifier itself
is still turned off (the tube is not powered at all).
The control of the amplifier is accessible during "OFF LINE" and "ON LINE" states, each having several
information screens and control functions (see Fig.3-2):
POWER ON S.3
OFF LINE S.5 (ON/OFF S4.1) ON LINE S.4
(NEXT or PREV) (PREV+NEXT) (PREV+NEXT)
(+2sec)
INFORMATION S.4-4
Forward Power
Reflected Power Tuning S.4-3 LCD adj. S.5-1
(PREV+NEXT) S.5-1 (OPER) S.5-3 Output Power TRI
Contrast 1...9 (PREV) List of Antenna VSWR
Back-light 1...5 (NEXT) Auto-Prot. Drive RF Power (PREV+NEXT)
Signatures RF Power Gain Auto-Operate S.5-2
(PREV)--(NEXT) Plate Current
(PREV+NEXT) S.5-2 High Voltage
Auto-Operate OFF (PREV) Plate RF Peak
Auto-Operate ON (NEXT) Screen Current
DC Power Input
Exh. Air Temp.
Fig.3-2 Information Screens and Control Functions Structure
Use the OPER button to alternatively change between operate and standby modes (S.4-2) during "ON LINE".
Please note that Auto-Operate might be enabled (see S.4-2). The same button activates signature list while "OFF
LINE".
The PREV and NEXT buttons change information screens or select control functions (S.4-4) for both "OFF
LINE" and "ON LINE".
The ON/OFF button alternatively switches OFF and "ON LINE".
You can proceed in one of two directions:
a) You can use the "OFF LINE" information screens and control functions. They refer to the auto-protection
signatures list, LCD contrast and back-lighting control, as well as the Auto-Operate feature. This is described
in S5.
b) You can turn on the amplifier and begin the warm-up sequence. After 2.5 minutes you may tune and start
operating the amplifier and you can use the "ON LINE" information screens or control functions (see below).
4. OPERATION
Operation of the amplifier is simplified due to the TRI tuning aid, Auto-Operate function, and automatic
protection system, so you'll be able to begin using it immediately after the installation. However, to make full
use of amplifier's potential and to fully configure it to your local conditions, we recommend that you thoroughly
read the following information.

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There are 14 "ON LINE" information screens, which can be consecutively selected by pressing the NEXT or
PREV buttons (see fig.3-2). Their purpose and method of use are described in the next five sections 4-1
through 4-5.
4-1. Turning ON and OFF
In order to turn on the amplifier, while the Main Power Switch (located on the rear panel) is on, press the red
ON/OFF button (on the right-bottom corner of the front panel) and hold it on for about 1 second. The LCD
back-lighting will light and the ON/OFF LED indicator above the button will change from red to green. You'll
hear the blower start first at high speed, then slow down.
After successfully passing the initial self-tests, the ON/OFF LED begins flashing green while the following
inscription on the LCD remains lit:
WARMING UP: nnn s
(nnn above is the number of seconds remaining to readiness for operation)
A tube warm-up period of 2.5 minutes follows. During this time the amplifier remains in standby mode, so you
can continue operating with the transceiver.
Pressing either the PREV or NEXT buttons during this period will result in changing to one of the 14 available
information screens described in S.4-4 below. This action will not influence the warming-up process, so you
may pass through all information screens, for instance to monitor the value of the High Voltage, or the
Exhaust Air temperature. You can also return to the old screen to see how many seconds are still needed for
the tube's heater.
N O T E
When you intend to have a short operating break, it is better to leave the amplifier in standby mode instead of
turning it off. By repeatedly turning the heater voltage on and off, the tube life is shortened. However, if you
unintentionally power-off the amplifier, it is best to switch it on again immediately. When the pause is short (up
to 1 minute) and the cathode is still warm, the warm-up period is shortened significantly, which reduces the
waiting time and prolongs the tube's expected life.
After the indicated period expires, the ON/OFF button stops flashing and lights green constantly. If the auto-
operate function is enabled (see S.5-2), the green OPER LED lights too. The last used (one out of 14)
information screen appears on the LCD, for instance: "WARMING UP: Ready".
The bargraph on the upper line always shows the peak forward power, even during "OFF LINE".
In order to turn the amplifier off press shortly the red ON/OFF button. If you are not going to use the amplifier
for a long time, it is best to turn it off using the Main Power switch (on the rear panel) as well.
4-2. Changing Operate and Standby Modes
With the Auto-Operate function disabled (see S.5-2), the OPER button changes two modes alternatively.
When Auto-Operate is ON, the amplifier will be maintained to operate mode by default, unless you use the
OPER button to go to standby intentionally (then Auto-Operate is suppressed temporarily). Pressing OPER
again would go to operate and enable the Auto-Operate again.
4-3. Tuning
Tuning is possible only in operate mode, so press the OPER button in order to illuminate its LED (unless
Auto-Operate is active).
a) Preliminary information.
Tuning the amplifier is a procedure of matching the impedance of the currently used antenna to the optimum
tube load resistance. This will ensure maximum plate efficiency and RF gain at nominal output power, with
minimum IMD.

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Please note, that the REFLECTED POWER readings and the measured VSWR depend on the load
impedance only, and not on the amplifier tuning. If the load impedance is different from 50-Ohm pure resistive
(nominal), the REFLECTED POWER reading will always indicate reflected power presence (even at excellent
tuning). The proper tuning will allow you to operate at greater power without distortion or danger to the
amplifier.
Note also that the real OUTPUT POWER in the load is equal to the difference between the FORWARD- and
REFLECTED- readings. For instance, at a reading of FORWARD 1200W, and of REFLECTED 200W, the
real OUTPUT POWER is 1000W (into a 2.6:1 VSWR load). At very high VSWR (no antenna or badly
mismatched antenna), the FORWARD and REFLECTED readings will be almost equal, while the real
OUTPUT POWER (the difference between them) will be practically zero.
The amplifier can operate safely if the following rule is obeyed: "REFLECTED POWER < 300W". Matching is
assured for loads with VSWR up to 3:1. Nevertheless, for some loads matching is possible at even higher
VSWR. For instance, you'll get a ** REFLECTED POWER ** soft-fault protection trip at full-scale (1200W)
forward, with more than 300W reflected (900W output power), when antenna VSWR exceeds 3.5:1.
C A U T I O N
Using a feeder of coaxial cable at VSWR > 2:1 on six meters band is not recommended. At such high values
of VSWR, the high voltages, high currents, and heat associated with line losses, risk to permanently damage
your coaxial cable or antenna switch.
Update tuning periodically, even if you have not changed your antenna, in particular when a significant
change in the environment occurs (snow, ice, newly appeared or removed massive objects, any wires nearby
etc.) that would cause significant changes in the antenna impedance.
N O T E
If you use more than one antenna, it is necessary that you select the proper antenna BEFORE the next step.
Retune after selecting a different antenna, since both impedances may differ substantially (unless their
VSWR is excellent, i.e. below 1.1:1 for both).
C A U T I O N
When tuning, do not apply continuous drive longer than 3 minutes and after that pause 1-2 minutes for tube
cooling.
We recommend that you tune-up at the center frequencies of the preferred frequency segment. First preset
both capacitor knobs TUNE and LOAD to approximately middle positions.
b) Selecting the plate-load "True Resistance Indicator (TRI)" tuning aid.
You may select TRI scale in three different ways:
- By pressing simultaneously for a moment the PREV+NEXT buttons. This will insert a 6dB attenuator
between the driver and the amplifier's input (the ATT LED will light), so you'll not need to reduce the drive
power during tuning. Press the PREV+NEXT buttons momentarily again to switch the attenuator off the input
and to return to the previous display. If you would use any of the PREV or NEXT buttons only, the attenuator
would be switched off, too, but the information screen would change to respectively previous or next;
- By pressing successively either the PREV or NEXT button (whichever is nearest), until you reach the TRI
scale. This will not insert the attenuator, so you should use less than 20W drive (unless the amplifier is almost
tuned), otherwise the next step would be executed automatically;
- By simply applying a normal drive power (50-60W), while the amplifier is not yet tuned. This will
automatically invoke the TRI tuning aid and will insert the input attenuator (the ATT LED will light) after one
second of transmission. The attenuator will be switched off, and the old screen will be returned automatically,
after you release the PTT shortly. If you have meanwhile achieved a nearly good tuning, the attenuator would
not be inserted again. If the old screen was the same (TRI, selected manually earlier), you'd then be able to
precisely tune the amplifier also at nominal power, without changing drive at all. Use this hint to shorten the
tuning process duration.

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c) Tuning Procedure.
While a continuous (CW) signal at the desired frequency is still applied:
- Look at the upper scale (forward power); obtain maximum power using the upper (TUNE) knob;
- Look at the lower (Load Cap) scale and turn the lower (LOAD) knob in order to center the “V”-marker at the
"!" mark.
- Release the PTT shortly in order to disable the attenuator, then repeat both steps at nominal power. Always
finish by peaking with the TUNE knob.
N O T E
Appearance of an arrow on either the left or right TRI scale edges means that the LOAD knob is too far from
the proper position. To correct for this, turn the LOAD knob to the prompted direction until the “V”-marker
appears inside the scale field. Then center it.
iiiii iiiiiiiii iiiiii iiiiiiiiiiiiii
-----!----- >----!----- -----!----< -----!---v- -----v-----
no marker: marker is far left: marker is far right: marker inside: LOAD is tuned:
use TUNE knob turn LOAD knob turn LOAD knob turn LOAD knob turn TUNE knob
for max.P pointer to the right pointer to the left slightly to the left to peak Forward
to get any marker until marker is inside until marker is inside to center it Power & finish.
Fig.4-1. Using TRI tuning aid
Please note also, that the TRI mark will not appear until at least 5W drive is applied, and at least 20W forward
power is achieved.
If, for some reason, matching cannot be accomplished successfully, check antenna selection and VSWR at
same drive frequency.
d) Tuning hints.
While rotating knobs, you'll note that both tunings would be virtually independent. This is a benefit of the TRI.
The plate-load resistance increases to the right and decreases to the left of the TRI center.
The center of the scale corresponds to the proper LOAD capacitor tuning, which presents an optimum load
resistance to the tube.
If you tune to the right, you'll obtain more gain, but less undistorted output power will be attainable. You may
prefer to use this hint when your drive power is insufficient or when you need less output but better efficiency,
for instance at heavy duty modes (RTTY, SSTV etc) where less heat is wanted.
Tuning to the left of the center would lead to the opposite: less gain and more power attainable. Of course,
this requires more drive power, more plate current, and more plate heat, which shortens tube's expected life,
as its cathode would be faster exhausted.
You might use the off-center tuning hint also to compensate for mains voltage variations in order to maintain
tube efficiency: tune to the right when mains is higher, or tune to the left if it's lower than the nominal voltage.
Please see S.2-2 (Line Voltage Selection) for more than 10% difference from the nominal.
4-4. "ON LINE" Information Screens and Control Functions.
a) Besides the Warming Up and TRI (described above in S.4-1 through S.4-3), you have 12 more Information
screens available. They are as follows: Forward Power, Reflected Power, Output Power (difference between
forward and reflected), Antenna VSWR, Drive RF Power, RF Power Gain, Plate Current, High Voltage, Plate
RF Peak, Screen Current, DC Power Input (product of plate current and high voltage), and Exhaust Air

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Temperature (Celsius and Fahrenheit scales). You can use them to monitor the technical state of the
amplifier and the associated parameters in digital form.
Selection is made by the PREV and NEXT buttons. You may change them in a closed loop, while the
amplifier is used and controlled in operate and standby modes, changes transmit and receive, without any
influence by the measuring process.
b) You can control LCD adjustment and Auto-Operate feature selection also while "ON LINE". The method is
the same as described for "OFF LINE", so see S.5-1 and S.5-2 for details.
4-5. Auto-Protection System
When any abnormal condition is detected, the amplifier will evaluate the risk and may use three different
degrees of protection, depending on the nature of the problem. Each event is accompanied by a text telling
you the reason. The back-light of the LCD is flashed meanwhile in order to attract the operator's attention.
a) The first degree of protection is issuing a warning message only, without any influence on the transmitting
process. This might be for instance "Reduce Drive", "Plate Current", etc. You could continue to transmit under
such conditions but you are close to a trip threshold.
b) The second degree of protection is a trip in standby mode (Soft Fault). You'll get an appropriate message,
for instance ** GRID CURRENT **. All Soft-Fault messages are marked with two asterisks on both screen
edges. The message remains on the display until you press any button (or Auto-Operate function returns to
operate mode automatically). The Soft Faults are of such kind where you can correct exploitation conditions
operatively (using less drive, improving VSWR, etc).
c) The third degree of protection is a trip in off mode (Auto-Protection).
You'll get the corresponding signature (see S.6-5 - Troubleshooting). If you cannot guess what the reason is,
you may try to turn the amplifier on again in order to check whether it's not an accidental condition. If the
problem persists, you'll need to contact your dealer - see S.1-2.
N O T E
The 6dB input attenuator is automatically inserted about 1 second after a bad tuning is detected at drive
levels above 20W. It is switched off at every PTT release (unless inserted manually).
5. "OFF LINE" OPERATION
There are two control functions and 14 information screens available in this state of the amplifier. You can
control the LCD contrast and back-lighting or enable/disable the Auto-Operate feature. You can also list the
auto - protection signatures. The tube is not powered at all (only the micro-controller is active) during these
operations.
5-1. Contrast and Back-lighting control
Press the PREV+NEXT buttons simultaneously and hold them for two seconds. The back-lighting of the LCD
will light and the "Contrast=... B.Light=..." screen will appear on the bottom line. Control the contrast of the
LCD using the PREV button in steps from 1 to 9. Control the back-lighting of the LCD using the NEXT button
in steps from 1 to 5.
Press shortly the PREV+NEXT buttons in order to reach the Auto-Operate function (see next S.5-2), or leave
buttons unused for 20 seconds if you want to accept these selections only (in order not to change Auto-
Operate inadvertently).
5-2. Auto-Operate enabling and disabling
When enabled, this function will save manual actions and operating time for you. It will automatically execute
operate commands every time when needed. The OPER button will be still functional, so you'll be able to
change to standby and back to operate manually at any time. After returning to operate the first time (by
pressing OPER button again), the Auto-Operate feature will be restored.

14
In order to enable or disable the Auto-Operate at all, after a contrast and back-light selection (see the
previous S.5-1), continue with pressing shortly the PREV+NEXT buttons. The "Auto Operate = ..." screen will
appear on the bottom line. Use the PREV button to select OFF or use the NEXT button to select ON. Press
shortly the PREV+NEXT buttons again to accept and return.
N O T E
If LCD back-lighting or contrast are too low, thus no characters are seen on the LCD, execute S.5-1 first to
obtain a readable display. All selections you make are stored in the nonvolatile memory of the amplifier and
are used at the next power-on. If no selection is made for 20 seconds, the currently existing selection is
accepted and the function is left automatically.
5-3. Reading Auto-protection Signatures
On every Hard Fault protection trip of the amplifier, signature information is stored in its nonvolatile memory.
The 7 most recent auto-protection trip signatures related to the amplifier internal status are stored there,
which you can copy and forward to your dealer for diagnostics.
In order to read and copy them press the OPER button while "OFF LINE". The back-lighting of the LCD will
light and you'll see the beginning of the signatures list. Use the NEXT and PREV buttons to navigate through
7 pairs of screens. For each auto-protection trip there is a pair of information screens, beginning with nA...
and nB... where:
- "n" is the number of the event (nr.1 is the last, nr.7 is the oldest one);
- A and B mark the first and the second part of an information screen pair.
Two lines, three groups by six symbols (36 symbols in total) are to be copied concerning every one of the 7
memorized events from 1A-1B through 7A-7B. To decode the signatures please see S.6-5 (Troubleshooting).
N O T E
After every signature listing the tube warm-up time is reset to 150 seconds regardless of the time being in
"OFF LINE" state.
6. MAINTENANCE
If no characters are seen on the LCD at power on maybe its contrast needs adjustment - see S.5-1.
6-1. Cleaning
W A R N I N G
Do not use solvents for cleaning - they may be dangerous both for you and for the amplifier paint or plastics.
Do not open the amplifier. Cleaning of the amplifier outer surfaces can be done with a piece of soft cotton
cloth lightly moistened with clean water.
To clean the air filter (located on the air-intake opening of the rear panel), remove the plastic frame and wash
the plastic foam with water. Re-install it after drying. Clean it periodically, depending on the circumstance dust
and amplifier use.
6-2. Fuses Replacement
If it is necessary to replace the mains fuses, use only standard ones.
The two Primary Mains Fuses of the amplifier are located on the rear panel (Fig. 2-1). They are 10A/250V for
200-240 VAC operation, and 20A/250V for 100-120 VAC operation, Quick-Blow type (Fast Acting), 1-1/4 x
1/4 inch Cartridge Fuses, Size "0" Ceramic.
Besides the primary fuses, on the MAINS PCB (inside the amplifier) there are three more small glass fuses
5x20mm, Slow-Blow type (F1-200mA, F2 and F3-2A) which are not replaced by the user. This is a

15
complicated and potentially dangerous operation. Should one of these fuses be blown, it may be indicative of
other failures. For this reason, we recommend this work be carried out by a trained service technician.
6-3. Tube Replacement
A single 4CX800A (GU74B) high-performance ceramic-metal tetrode manufactured by Svetlana is employed
in the amplifier. Replacement is a complicated and potentially dangerous operation. The idling plate current
must be adjusted after a replacement. For this reason, we recommend this work be carried out by a trained
service technician.
6-4. The ACOM1006 Simplified Schematic Diagram
See Fig.6-1 ACOM1006 Simplified Schematic Diagram.* The high-performance ceramic-metal tetrode
4CX800A (GU74B) from Svetlana (V1), with a plate dissipation of 800W, is grid-driven. The input signal from
the RF INPUT jack is fed through an input matching circuit, which comprises some components in the INPUT
PCB and Rsw. This circuit tunes out the input capacitance of the tube. The swamping resistor Rsw is a
termination load for this circuit and can dissipate up to 100W of RF drive power.
The cathode resistor Rc creates DC and RF negative feedback, thus stabilizing the gain and equalizing the
frequency response. The varistor VSsg in the screen grid circuit stabilizes the tube regime against dynatron
effects and protects its screen grid, and voltage regulator in the events of a flashover.
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 circuit comprises LP,
LL, CP, and CL1-CL2 which form a classic Pi-L network and suppress the harmonic frequency emissions.
This tank is tuned over the band by the air variable capacitors CP and CL1. The output signal is fed through
an additional VHF low-pass filter for frequencies above 55MHz (Lf1, Lf2 and Cf) that minimizes the second
harmonic in the region of 100-108MHz and increases higher harmonics suppression. Then the output signal
is fed through the vacuum antenna relay K1, wattmeter current transformer TA1, and a high-pass filter RFC4-
Ca for frequencies below 100kHz, to the antenna output.
The chokes RFC3 and RFC4 keep track of the antenna relay contact conditions and together with Ca prevent
the plate DC high voltage from reaching the antenna. The choke RFC4 shunts it to ground if the DC blocking
capacitor Cb3 fails. The resistor Ra protects the amplifier from charging Electro-static energy fed by the
antenna.
The PLATE CAPACITIVE DIVIDER and RF WATTMETER are the main sources of information for the control
circuit of the amplifier during the antenna impedance matching process. The control circuit is based on the
80C552 micro-controller from Philips.
All voltages are delivered from the MAINS&LOW VOLTAGE and HIGH VOLTAGE SUPPLY PCBs. The
control grid, screen grid and plate currents, plate cooling airflow temperature, reflected power etc. are
permanently monitored. Many software-derived protections are based on this information.
* Detailed electrical schematic diagrams and PCB layouts are available on CD-ROM from ACOM or from your
dealer on request.

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Fig.6-1 ACOM1006 Simplified Schematic Diagram

17
5. Troubleshooting
See S.5-3 for the method of reading the auto-protection signatures. You can decode them using the
information below.* The signatures are structured in two lines, three groups by six symbols for every one
event of auto-protection. The last event is numbered as 1A-1B pair of lines, and the oldest one is 7A-7B.
The meaning of the first group is as follows:
a) nA - the number of the trip;
b) The next three symbols mean the following:
PN0 - tests made during Power-On procedure, before HV is ON;
PN2 - tests made during Power-On procedure, 1 second after HV is ON the step-start relay is closed;
SB0 - tests made in standby, during the warm-up period and while entering standby (from operate);
SB2 - tests made during standby (after the warm-up period);
PR0 - tests made while entering operate;
PR2 - tests made during operate;
TR0 - antenna relay tests made while changing from Tx to Rx (releasing the relay during operate)
TR2 - antenna relay tests made while changing from Rx to Tx (closing the relay during operate)
TR4 - antenna relay tests made during Tx (relay should be closed in operate mode)
TR6 - antenna relay tests made during Rx (relay should be open in operate mode)
c) The last symbol of the first group designates the kind of the input parameter, which caused the protection
to trip. The abbreviations in brackets below are the signal names/designations according to the CONTROL
PCB electrical schematic diagram and signal type:
1 - peak forward power (pfwd, analogue)
2 - reflected power (rfl, analogue)
3 - input (drive) power (inp, analogue)
4 - peak anode alternate voltage (paav, analogue)
5 - screen grid current (g2c, analogue)
6 - plate current (ipm, analogue)
7 - high voltage (hvm, analogue)
8 - exhaust air temperature (temp, analogue)
9 - drive power exists (*GRIDRF, logic)
A - antenna power exists (*PANT, logic)
B - output relay closed (ORC, logic)
C - arc fault (ARCF, logic)
D - control grid current too high (G1C, logic)
E - +24VDC power supply error (PSE, logic)
F - low airflow (LAIR, logic)
For instance, "1ASB07" in the first group would mean that the last auto-protection (1A) tripped by the tests
made in standby (SB), during the warm-up period (0), and the high voltage - hvm signal was failing (7).
The next five groups of symbols carry information about the analogue and logic values as measured by the
micro-controller (at the moment of auto-protection trip).
* Additional information is available from ACOM or from your dealer on how to interpret these values. Using
an EXCEL APPLICATION (available from ACOM or your dealer free of charge) and a PC, you can decode
these signatures easily by yourself. For instance, in the above example you could see what the value of HV
was at the moment when it has failed (it could be a too low or too high voltage which has tripped the
protection).
C A U T I O N
In case it is necessary to ship the amplifier please see S.7-3.

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7. SPECIFICATIONS
7-1. Parameters
a) Frequency Coverage: The six meters amateur band 50-54MHz, extensions and/or changes on request.
b) Power Output: 1000W PEP or continuous carrier, no mode limit.
In continuous carrier modes (RTTY etc.) for transmissions longer than 15 minutes (up to several hours
depending on ambient temperature), the external auxiliary fan must be mounted.
c) Intermodulation Distortion: Better than 35dB below rated output.
d) Hum and noise: Better than 40dB below rated output.
e) Harmonic Output Suppression: Better than 70dB below rated output.
f) Input and Output Impedances:
- Nominal value: 50 Ohm unbalanced, UHF (SO239) type connectors;
- Input circuit: VSWR less than 1.3:1, 50-54MHz (no tunings, no switching);
- Bypass path VSWR less than 1.1:1, 50-54MHz;
- Output (antenna) impedance matching capability: VSWR up to 3:1 or higher.
g) RF Gain: 12.5dB typically, frequency response less than 0.5dB (50 to 60W drive power for rated output).
h) Primary Power: 85-264V (100, 110, 120, 200, 210, 220, 230 & 240V nominal taps, +10% -15% tol.), 50-
60Hz, single phase, 2200VA consumption at rated output.
i) Complies with CE safety and electromagnetic compatibility requirements as well as FCC-regulations.
j) Size & Weight (operating): W422mm x D355mm x H182mm, 22kg.
k) Operating environments:
- Temperature range: 0...+50 degs. Celsius;
- Humidity: up to 75% @ +35 degs. Celsius.
- Height: up to 3000m above sea level without output deterioration.
7-2. Functions
a) Antenna Impedance Matching Process: plate-load "True Resistance Indicator" (TRI) aided.
b) T/R System: QSK operation with built-in, vacuum RF antenna relay (special quiet installation).
c) Protections:
- Cover interlock for operator's safety;
- Inrush power-on current control;
- High voltage, control grid, screen grid, and plate currents;
- Exhaust air temperature;
- T/R sequencing;
- Antenna relay contacts, including RF power induced in antenna from another nearby transmitter;
- Antenna matching quality;
- Reflected power;
- RF arcs, including in antenna system;
- Overdrive.

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d) Signatures of the amplifier internal status are stored in a nonvolatile memory for the seven most recent
auto protection trips.
e) Dot-matrix back-lighted alphanumeric LCD with bargraph for forward peak power and text messages to the
operator.
f) Measurement and constantly monitoring of 12 most important parameters of the amplifier via LCD.
g) Menu-selectable LCD Back-light and Contrast.
h) Tube: a single 4CX800A (GU74B) high-performance ceramic-metal tetrode of Svetlana with plate
dissipation of 800W, grid driven, forced-air cooling.
7-3. Storage and Shipment
C A U T I O N
Should you need to transport the amplifier, use the original packing as described below.
First, switch off the amplifier. Pull the mains plug out of the outlet. Disconnect all cables from the rear panel of
the amplifier (remove the ground connection the last). Finally, pack the amplifier in its original carton.
a) Storage environments: the amplifier can be kept packed in dry and ventilated unheated premises without
chemically active substances (acids, alkalis etc.) in the following climatic environment:
- Temperature range: -40 to +70 degs. Celsius;
- Humidity: up to 75% @ +35 degs. Celsius.
b) Shipping Size and Weight:
W590mm x D430mm x H305mm, 25kg.
c) Shipping environments: all types of transportation, including aircraft baggage section up to 12000 meters
above sea level.