Acom ACOM1000 User 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. Sa ety Considerations, Explicit De initions . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
2-1. Unpacking and Initial Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
2-2. Line Voltage Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2-3. Ampli ier Location Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2-4. Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
2-5. Installation o External Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
3. POWER ON, CONTROLS AN IN ICATORS . . . . . . . . . . . . . . . . . . .9
4. OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4-1. Turning ON and OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4-2. Changing Operate and Standby Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4-3. Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
4-4. ON LINE In ormation Screens and Control Functions. . . . . . . . . . . . . . . . .15
4-5. Auto-Protection System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5. OFF LINE OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
5-1. Contrast and Backlighting control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
5-2. Auto-Operate enabling and disabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
5-3. Reading Auto-protection Signatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

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6. MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
6-1. Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
6-2. Fuses Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6-3. Tube Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
6-4. The ACOM1000 Simpli ied Schematic Diagram . . . . . . . . . . . . . . . . . . . . . .17
6-5. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
7. SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
7-1. Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7-2. Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
7-3. Storage and Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

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1. GENERAL INFORMATION
1-1. Introduction and escription
This manual explains the installation, operation, and maintenance o the ACOM1000 HF+6 meters
linear ampli ier.
The ACOM1000 is a complete and sel -contained linear ampli ier that covers all amateurs bands rom
1.8 through 54MHz and provides over 1000W-output power with less than 60W-exciter drive. Antenna
VSWR up to 3:1 is acceptable at ull power. Tuning is substantially simpli ied by a plate-load True Resistance
Indicator (TRI) and by an automatically controlled input attenuator. Operating parameters are displayed
by a multi- unctional backlighted Liquid Crystal Display. Full break-in transmit/receive switching (QSK)
is standard.
1-2. Owner Assistance
I assistance is needed, you should contact your local dealer irst. I you still have an issue you need to
discuss with one o ACOMs specialists, the contact in ormation is as ollows: ax + 359 2 920 96 56,
tel. + 359 2 920 96 55, e-mail [email protected] or [e-mail] or by mail: bul. Gornobanski
Nr.151, 1330 So ia, Bulgaria.
1-3. Equipment Supplied
The ACOM1000 ampli ier and this manual are shipped in a cardboard carton.
1-4. Features
lEasy to operate. The TRI is a power ul tuning aid which, together with the automatically controlled
input attenuator, helps the operator to quickly and precisely match antennas (5-10 seconds typically).
The auto-operate unction (when enabled) maintains the ampli ier in OPERATE mode or you, thus
saving manual operations and time.
lNo heavy outboard antenna tuners required or antenna VSWR up to 3:1 (and higher on some
bands). Your ampli ier will per orm the unctions o an antenna tuner, thus enabling you to change
antennas aster and use them over a wider requency range (saving tuning time).
lAn ampli ier that is both user- riendly, and that looks a ter itsel . It is designed to sa ely withstand up
to 500W re lected power, up to 100 milliseconds duration o drive spikes, drive RF tails a ter a PTT
or KEY release, operators inadvertent tuning errors etc. It would also not cease to unction with a
so t AC line and would deliver more than hal power at only 75% o 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 ield days, DXpeditions, and other portable events.
lLCD comment display. All ampli ier status indications are explained via detailed text displayed on
the dot matrix backlighted liquid crystal display (LCD). The upper-lines strip on the LCD always reads
directly peak orward power. LED indicators are provided or OPERATE, attenuation-on, and
ON/OFF conditions.
lEasy maintenance. Signatures o the ampli ier internal status are stored in a nonvolatile memory or
7 most recent auto protection trips. This in ormation can be orwarded to your dealer or diagnostics.
Using an EXCEL APPLICATION (available rom ACOM or your dealer ree o charge) and a PC you can

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decode the signatures by yoursel , too.
lLess noise in the shack: the input bypassing and the vacuum antenna relays are virtually silent even in
QSK CW mode due to their special mounting.
lLess QRM and improved Electro Magnetic Compatibility during tuning. Antenna matching can be
achieved in less than 10 seconds at a quarter o nominal output power.
lOperates without special signals rom the transceiver - ground on TX and 60W RF drive power
are su icient.
lBroadband input matching circuit resulting in very good load to the transceiver over the entire
spectrum rom 1.8MHz up to 54MHz.
lUses a single 4CX800A (GU74B) Svetlana high-per ormance ceramic-metal tetrode with plate
dissipation o 800W ( orced air cooling, grid-driven).
lPermanent monitoring and protection o plate and grid voltages and currents, as well as o the
exhaust air temperature. The Bias Optimizer decreases the heat dissipated rom the tube, and there is
automatic protection against overheating in accordance with the speci ications o the tube producer.
lAn output RF Arc protection is employed. It sa eguards the ampli ier, antenna, antenna selector, and
tuner against severe damage in case o possible break down.
lHigh voltage power supply inrush current protection, which eliminates the danger o a ecting sensitive
devices, connected to the same mains circuit (important when used portable). The ampli ier can be
con igured or 5 nominal line voltages: 200, 210, 220, 230, and 240VAC, 50 or 60Hz (100, 110, and
120VAC on request).
lContinuous measuring and/or selectable monitoring o 12 most important parameters o the ampli ier,
exciter and antennas via LCD.
lThe ampli ier can be shipped with 10 and 12 meters capability disabled as required by the FCC or
US users. Contact your dealer about enabling those bands.
1-5. Safety Considerations, Explicit efinitions
The ACOM1000 HF+6 meters Linear Ampli ier is a Sa ety Class I unit. The third grounding lead o its
mains cord (which is colored yellow with two green stripes) and the ground stud on the rear panel o
the ampli ier, (marked GND) must be connected to the stations grounding system or sa e operation.
The ampli ier is designed to meet international sa ety standards and complies with CE sa ety and
electromagnetic compatibility requirements, as well as FCC regulations.
This operating manual contains in ormation, precautions, indications or cautions and warnings which
must be ollowed by the user to ensure sa e operation and to keep the ACOM1000 in sa e operating
condition.

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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, i not correctly per ormed, could result in
personal injury, ire hazard or electric shock.
C A U T I O N notes call attention to a procedure which, i not correctly per ormed, could result in
equipment damage, not only in the ampli ier.
N O T E notes call attention to a procedure which, i not correctly per ormed, 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. o not touch any part inside while the amplifier
is open because some residual voltages may still be present.
W A R N I N G HIGH VOLTAGE!
NEVER ALLOW ANYONE, ESPECIALLY CHIL REN,
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 liquids.
AVOI placing the amplifier in excessively dusty environments or in direct
sunlight. O 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
o 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
To avoid damage (not covered under warranty) read the Installation - Section 2 o
this operating manual care ully. I you have any doubts about the installation, operation
or sa eties o the ampli ier please consult your dealer.

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2. INSTALLATION
2-1. Unpacking and Initial Inspection
N O T E
Be ore you start to install the ampli ier, thoroughly read this manual. First, care ully
inspect the cardboard carton and its contents or physical damage. I damage is
noticed, noti y your dealer immediately. Delay may in ringe carriers warranty
conditions. Keep all packing or possible uture transportation!
2-2. Line Voltage Selection
C A U T I O N
To avoid damage (not covered under warranty), check care ully i the voltage or
which the ampli ier is set corresponds to your mains nominal voltage.
Normally the ampli ier is supplied set or a nominal line voltage o 240V. There might be exceptions in
cases o special delivery and then the voltage set is noted in the Table o Individual Data (Table 2-1). I
your power line has a di erent nominal voltage, it will be necessary or you to contact your dealer.
AMP s/n
Tube s/n
Voltage Selector VAC
Table 2-1. ACOM 1000 Individual Data
2-3. Amplifier Location Selection
C A U T I O N
The weight o the unit is about 22kg, which should pre erably be handled by two
persons.
Position the ampli ier near the place where it will be used. Youll need an easy access to the command
knobs and indicators area, as well as to the rear panel cabling.
No magnetic- ield sensitive devices should be located next to the right side o the ampli ier as its power
trans ormer is located there. Its best to position it to the right o your transceiver. No temperature
sensitive devices should be located above the exhaust hot air area, so dont push it under a shel . You
may pre er to use the bottom scales o both variable capacitor knobs (TUNE and LOAD) i you install
it on a shel . DO NOT OBSTRUCT AIR INTAKE (rear panel) and EXHAUST (top cover) areas o the
ampli ier. Keep a minimum distance o 10cm (4 inches) to the intake and 50cm (20 inches) to the
exhaust.

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2-4. Connections
Connection to your station must be accomplished in the order described below, be ore you apply
mains voltage to the ampli ier.
W A R N I N G
Note that the grounding system may have to withstand currents over 10A
with insignificant voltage drop on it. Therefore, it may be necessary to
improve it considerably, i.e. to become less resistive, with heavier leads and
lower-resistive ground path. The grounding leads should be at least 4mm²
(AWG 11 or SWG 13).
Fig.2-1 Connections
a) First, connect the ground stud o the ampli ier (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 rom the transceiver output to the ampli ier rear panel
RF INPUT socket.
C A U T I O N
I this is the irst time you will use a power ampli ier in your station, pay attention to
the coaxial cable type rom the ampli iers output. It must handle the increased
power sa ely, particularly on the 10 and 6 meters bands. We recommend, that you
use RG213 or better. Check the same or the antenna selector and tuner as well as
the antenna itsel (especially multi-band trap antennas).
c) Connect a coaxial cable rom the ampli ier output (on the rear panel, marked RF OUTPUT) with a
PL-259 plug to the antenna selector or tuner or to the antenna or the respective band.
d) Run a cable terminated in a Phono (RCA) connector rom the transceiver socket providing ground
on transmit to the ampli ier rear panel KEY-IN socket.

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N O T E
Your ampli ier will not work i KEY-IN is not connected properly.
Transceiver producers give di erent names to this output and they are or instance TX-GND, SEND,
T/R-LINE, etc. Some transceivers require that ground on transmit is implemented via a so tware
command, or by changing the setting o a switch on the rear panel, or interior o the transceiver. Check
your transceivers manual.
e) The KEY-OUT socket on the rear panel provides an extra control signal rom the ampli ier to the
transceiver. It could be used to improve the transmit/receive switching sa ety.
I your transceiver has a suitable input that disables transmission, we recommend that you connect it
with a cable terminated in a Phono (RCA) connector to the KEY-OUT socket o the ampli ier. Transceiver
producers give di erent names to this input and they are or instance TX-INHIBIT, MUTE, LINEAR,
etc. Check your transceivers manual or consult your dealer.
I your transceiver does not have such input, dont worry - the ampli ier will unction normally as well,
and then the KEY-OUT may remain unused.
) Preparation o wall outlet or the ampli ier.
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 di erent standards in di erent countries, the mains plug is supplied and mounted by the
dealer. He connects to the mains cord end a standard mains supply plug which meets the Sa ety Class I
units standard in your country. The ground lead o the ampli iers power cord is colored yellow with
two green stripes and the blue and brown leads are active. When the ampli ier is to be used with only
one mains use, it is connected in series with the brown lead, which must be the active. I you have any
doubts about the correct way o connecting the wires, consult your dealer.
W A R N I N G
Before connecting the amplifier to your mains supply, be sure that the supply
is correctly wired, and is adequate for the current drawn by the amplifier
(up to 10A). Make certain that the grounding lead is connected properly in
the wall outlet for the amplifier.
It is pre erable that you use the wall outlet closest to the source. The installation leads should be at least
1.5mm² (AWG 15 or SWG 17). Check i the respective uses can handle current up to 10A, as well, as
i the voltage corresponds to the voltage or which the ampli ier is set (S.2-2). I you connect the ampli ier
to a di erent mains outlet, be sure that you check it, too.
Make sure the main Power Switch on the rear panel is in OFF position and insert ampli iers mains plug
into the wall outlet prepared or it. The ampli ier remains switched o .

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2-5. Installation of External Fan
This an (Fig. 2-1) is not necessary in SSB and CW modes, nor in continuous carrier modes (RTTY, SSTV
etc.) with carrier down times o maximum 15 minutes and a subsequent pause o 3 minutes. For higher
duties or ambient temperatures the an is recommended. The auxiliary an (92x92mm) must be brushless
type, 2...5W/24VDC. It may be installed by your dealer or by the manu acturer on request.
3. POWER ON, CONTROLS AN IN ICATORS
C A U T I O N
Do not turn the ampli ier on or at least 2 hours a ter unpacking it in the room
where it will be used. Pay particular attention when you move it rom a very cold
into a very warm place - condensation is likely and this could result in damage to the
high voltage circuits. In such a case, wait at least 4 hours. A similar e ect can occur
a ter a rapid warming o the operating room ( or instance a ter switching on a
power ul heater in a cold shack).
C A U T I O N
To avoid damage (not covered under warranty) care ully check that the voltage or
which the ampli ier is set corresponds to your mains nominal voltage (see S.2-2 and
table 2-1).
A ter ollowing all instructions in S.2, you can turn ON the main power switch marked LINE on the
rear panel (Fig.2-1). The red LED indicator above the red ON/OFF button located on the ront panel
must light red and a black inscription ACOM1000 will appear on the LCD (Fig.3-1):
Fig.3-1 ACOM1000 Display and Control
Youll note that the upper line o the LCD always reads directly peak orward power, even while the
tube is not driven. The 1200W scale resolution is 10W per bar, dots division weight is 60W, and igures
are multiple to 300W. Note also that levels below 20W may be not detected.

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N O T E
I the characters on the LCD are dim or not readable, please ollow the method o
LCD contrast and backlighting adjustment described in S.5-1.
In this position (called OFF LINE herea ter) only the micro-controller is operational, while the ampli ier
itsel is still turned o (the tube is not powered at all).
The control o the ampli ier is accessible during OFF LINE and ON LINE states, each having several
in ormation screens and control unctions (see Fig.3-2):
POWER ON
OFF LINE (ON/OFF) ON LINE
(PREV+NEXT) (PREV+NEXT)
(PREV+NEXT)
(PREV+NEXT)
(PREV+NEXT)
(NEXT or PREV)
Contrast 1...9
Back-light 1...5 (NEXT)
(NEXT)
(PREV)
(PREV)
A to-Operate OFF
A to-Operate
A to-Operate ON
(OPER)
List of
A to-Prot.
Signat res
(PREV)--(NEXT)
INFORMATION
Forward power
Reflected power
O tp t Power
Antenna VSWR
Drive RF Power
RF Power Gain
Plate C rrent
High Voltage
Plate RF Peak
Screen C rrent
DC Power Inp t
Exh. Air Temp.
T ning
TRI
(+2sec)
LCD adj.
S.5
S.3
S.4S.4-1
S.4-4 S.4-3
S.5-1
S.5-1
S.5-2
S.5-2
S.5-3
Fig.3-2 In ormation Screens and Control Functions Structure
The OPER button alternatively changes operate and standby modes (S.4-2) while ON LINE. Please
note that Auto-Operate might be enabled. The same button activates signature list while OFF LINE.
The PREV and NEXT buttons change in ormation screens or select control unctions (S.4-4) or both
OFF LINE and ON LINE.
The ON/OFF button alternatively switches OFF LINE and ON LINE states o the ampli ier.
You can proceed in one o two directions:
a) You can use the OFF LINE in ormation screens and control unctions. They re er to the auto-protection
signatures list, LCD contrast and backlighting control, as well as the Auto-Operate eature. This is
described in S5.
b) You can turn on the ampli ier and begin the warm-up sequence. A ter 2.5 minutes you may tune and
start operating the ampli ier and you can use the ON LINE in ormation screens or control unctions
(see below).

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4. OPERATION
Operation o the ampli ier is simpli ied due to the TRI tuning aid, Auto-Operate unction, and automatic
protection system, so youll be able to begin using it immediately a ter the installation. However, to
make ull use o ampli iers potential and to ully con igure it to your local conditions, we recommend
that you thoroughly read the ollowing in ormation.
There are 14 ON LINE in ormation screens, which can be selected by pressing repeatedly the NEXT
or PREV buttons (see ig.3-2). Their purpose and method o use are described in the next ive sections
4-1 through 4-5.
4-1. Turning ON and OFF
In order to turn on the ampli ier, while the Main Power Switch (located on the rear panel) is on, press
the red ON/OFF button (on the ront panel right-bottom corner) and hold it on or about 1 second.
The LCD backlight will light and the ON/OFF LED indicator above the button will change rom red to
green. Youll hear the blower start irst at high speed, then slow down.
A ter success ully passing the initial sel -tests, the ON/OFF LED begins lashing green while the ollowing
inscription on the LCD remains lit:
WARMING UP: nnn s
(nnn above is the number o seconds remaining to readiness or operation)
A tube warm-up period o 2.5 minutes ollows. During this time the ampli ier 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 the screen to one
o the 14 available in ormation screens described in S.4-4 below. This action will not in luence the
warming-up process, so you may pass through all in ormation screens, or instance to monitor the High
Voltage value or the Exhaust Air temperature. You can also return to the old one to see how many
seconds are still needed or the tubes heater.
N O T E
When you intend to have a short operating break, it is better to leave the ampli ier
in standby mode instead o turning it o . Tube li e is shortened by repeatedly turning
on and o the tube heater supply. However, i you unintentionally power-o the
ampli ier, 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 signi icantly,
which reduces the waiting time and prolongs the tubes expected li e.
A ter the indicated period expires, the ON/OFF button stops lashing and lights green constantly. I the
auto-operate unction is selected to ON (see S.5-2), the green OPER LED lights too. The last used (one
out o 14) in ormation screen appears on the LCD, or instance: WARMING UP: Ready.
The bargraph on the upper line always indicates the peak orward power (as well as during OFF LINE).
In order to turn the ampli ier o press shortly the red ON/OFF button. I you are not going to use the
ampli ier or a long time, it is best to turn it o using the Main Power switch (on the rear panel) as well.

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4-2. Changing Operate and Standby Modes
With the Auto-Operate unction disabled (see S.5-2), the OPER button changes two modes alternatively.
When Auto-Operate is ON, the ampli ier will be maintained to operate mode by de ault, unless you
use the OPER button manually to go to standby (then Auto-Operate is suppressed temporarily). Pressing
OPER again would restore the Auto-Operate.
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 in ormation.
Tuning the ampli ier is a procedure o matching the impedance o the currently used antenna to the
optimum tube load resistance. This will ensure maximum plate e iciency and RF gain at nominal output
power, with minimum IMD at that.
Please note, that the REFLECTED POWER readings and the measured VSWR depend on the load
impedance only, and not on the ampli ier tuning. I the load impedance is di erent rom 50-Ohm pure
resistive (nominal), the REFLECTED POWER reading will always indicate re lected power presence
(even at excellent tuning). The proper tuning will allow you to operate at greater power without distortion
or danger to the ampli ier.
Note also that the real OUTPUT POWER in the load is equal to the di erence between the FORWARD-
and REFLECTED- readings. For instance, at a reading o FORWARD 1200W, and o 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 di erence between them) will be practically zero.
The ampli ier can operate sa ely i the ollowing rule is obeyed: REFLECTED POWER < 500W.
Matching is assured or loads with VSWR up to 3:1. Nevertheless, or some loads and bands matching is
possible at even higher VSWR. For instance, youll get a
** REFLECTED POWER ** so t- ault protection trip at ull-scale (1200W) orward, with more than
500W re lected (700W output power), when antenna VSWR exceeds 4.5:1.
C A U T I O N
Using a eeder o coaxial cable at VSWR > 3:1 on HF, and particularly on the 10 and
6 meters bands, is not recommended. At such high values o 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 i you have not changed band or antenna, in particular when a signi icant
change in the environment occurs (snow, ice, newly appeared or removed massive objects, alien wires
nearby etc.) that would cause signi icant changes in the antenna impedance.

13
N O T E
I you use more than one antenna per band, it is necessary that you select the proper
antenna BEFORE the next step. Retune a ter selecting a di erent antenna or the
same band, since both impedances may di er substantially (unless their VSWR is
excellent, i.e. below 1.2:1 or both).
C A U T I O N
Do not switch the BAND switch knob while transmitting with the ampli ier! Hot
switching (while transmitting) will eventually destroy the band switch, not covered
by the warranty!
C A U T I O N
When tuning, do not apply continuous drive longer than 3 minutes and a ter that
pause 1-2 minutes or tube cooling.
We recommend that you tune-up at the center requencies o the pre erred requency band. First
select the band switch (never with RF applied!). Then use table 4-1 in order to achieve an approximate
preset or both TUNE capacitor and LOAD capacitor knobs:
zHM,dnaBlaibonKenuTlaibonKdaoL
2-8.105-5754-57
4-5.3 03-05 06-77
3.7-704-3466-37
2.01-1.01 01-21 03-23
53.41-4154-5542-62
2.81-81 36-16 25-45
54.12-1271-4433-53
52-9.42 18-97 94-74
7.92-8202-6423-63
45-05 51-04 21-61
Table 4-1. Approximate tuning preset
b) Selecting the plate-load True Resistance Indicator (TRI) tuning aid.
You may select TRI scale in three di erent ways:
- By pressing simultaneously or a moment the PREV+NEXT buttons. This will insert a 6dB attenuator
between the driver and the ampli iers input (the ATT LED will light), so youll not need to reduce the
drive power during tuning. Press PREV+NEXT buttons momentarily again to switch the attenuator o
the input and to return to the old screen. I you use any o PREV or NEXT buttons only, the attenuator
would be switched o too, but the in ormation screen would change to respectively previous or next.
- By pressing repeatedly either PREV or NEXT button (whichever is nearest), until you reach the TRI
scale. This will not insert the attenuator, so youll have to use less than 20W drive (unless the ampli ier
is nearly correctly tuned), otherwise the next step would be executed automatically:
- By simply applying a normal working (50-60W) drive power, while the ampli ier is not yet tuned.

14
This will automatically invoke the TRI tuning aid and will insert the input attenuator (the ATT LED will
light) a ter one second. The attenuator will be switched o , and the old screen will be returned
automatically, a ter you release the PTT shortly. I you have achieved meanwhile a nearly good tuning,
the attenuator would not be inserted again. I the old screen was the same (TRI, selected manually
earlier), youll then be able to precisely tune the ampli ier also at nominal power, without changing drive
at all. Use this hint to shorten the tuning process duration.
c) Tuning Procedure.
While a continuous (CW) signal at the desired requency is still applied:
- Look at the upper scale ( orward 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 triangle
marker at the ! mark.
- Release the PTT shortly in order to disable the attenuator, then repeat both steps at nominal power.
Always inish by peaking with the TUNE knob.
N O T E
Appearance o an arrow on either le t or right TRI scale edges means that the LOAD
knob is too ar rom the proper position. To correct or this, turn the LOAD knob to
the prompted direction until the triangle marker appears inside the scale ield.
I_____
! _____ IIII ____> ! _____ IIIIIIIIIII _____ ! <____ IIIIIII _____ ! ___v__ IIIIIIIIIIIIIIII _____ v _____
:rekramon
robonkENUTesu
ynategotP.xam
.rekram
:telraasirekram
bonkDAOLnrut
litnuthgirotretniop
.edisnirekram
:thgirraasirekram
bonkDAOLnrut
litnutelotretniop
.edisnirekram
:edisnirekram
bonkDAOLnrut
ottelylthgils
.tiretnec
:denutsiDAOL
otbonkENUTnrut
drawroFkaep
.hsini&rewoP
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
orward power is achieved.
I , or some reason, matching cannot be accomplished success ully, check BAND switch and antenna
selection. Then check the antenna VSWR at same drive requency.
d) Tuning hints.
While turning knobs, youll note that both tunings would be virtually independent. This is a bene it o
the TRI. The plate-load resistance increases to the right and decreases to the le t o the TRI center.
The center o the scale corresponds to the proper LOAD capacitor tuning, which presents an optimum
load resistance to the tube.
I you tune to the right, youll obtain more gain, but less undistorted output power will be attainable.
You may pre er to use this hint when your drive power is insu icient or when you need less output but
better e iciency, or instance at heavy duty modes (RTTY, SSTV etc) where less heat is wanted.
Tuning to the le t o the center would lead to the opposite: less gain and more power attainable. O
course, this requires more drive power, more plate current, and more plate heat, which shortens
tubes-expected li e, as its cathode would be aster exhausted.

15
You might use the o -center tuning hint also to compensate or mains voltage variations in order to
maintain tube e iciency: tune to the right when mains is higher, or tune to the le t i its lower than the
nominal voltage. Please see S.2-2 (Line Voltage Selection) or more than 10% di erence rom 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
In ormation screens available. They are as ollows: Forward Power, Re lected Power, Output Power
(di erence between orward and re lected), Antenna VSWR, Drive RF Power, RF Power Gain, Plate
Current, High Voltage, Plate RF Peak, Screen Current, DC Power Input (product o plate current and
high voltage), and Exhaust Air Temperature (Celsius and Fahrenheit scales). You can use them to monitor
the technical state o the ampli ier and the associated parameters in digital orm.
Selection is made by the PREV and NEXT buttons. You may change them in a closed loop, while the
ampli ier is used and controlled in operate and standby modes, changes transmit and receive, without
any in luence by the measuring process.
b) You can control LCD adjustment and Auto-Operate eature selection also while ON LINE. The
method is the same as it is described or OFF LINE, so see S.5-1 and S.5-2 or details.
4-5. Auto-Protection System
When any abnormal condition is detected, the ampli ier will evaluate the risk and may use three di erent
degrees o protection, depending on the nature o the problem. Each event is accompanied by a text
telling you the reason. The backlight o the LCD is lashed meanwhile in order to attract the operators
attention.
a) The irst degree o protection is issuing a warning message only, without any in luence on the
transmitting process. This might be or 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 o protection is a trip in standby mode (So t Fault). Youll get an appropriate
message, or instance ** GRID CURRENT **. All So t-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
unction returns to operate mode automatically). The So t Faults are o such kind where you can correct
exploitation conditions operatively (using less drive, improving VSWR, etc).
c) The third degree o protection is a trip in o mode (Auto-Protection).
Youll get the corresponding signature (see S.6-5 - Troubleshooting). I you cannot guess what is the
reason, you may try to turn the ampli ier on again in order to check whether its not an accidental
condition. I 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 a ter a bad tuning
is detected at drive levels above 20W. It is switched o at every PTT release (unless
inserted manually).

16
5. OFF LINE OPERATION
There are two control unctions and 14 in ormation screens available in this state o the ampli ier. You
can control the LCD contrast and backlighting or enable/disable the Auto-Operate eature. 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 Backlighting control
Press the PREV+NEXT buttons simultaneously and hold them or two seconds. The back-lighting o
the LCD will light and the Contrast=... B.Light=... screen will appear on the bottom line. Control
the contrast o the LCD using the PREV button in steps rom 1 to 9. Control the backlighting o the
LCD using the NEXT button in steps rom 1 to 5.
Press shortly the PREV+NEXT buttons in order to reach the auto-operate unction (see next S.5-2),
or leave buttons unused or 20 seconds i 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 unction will save manual actions and operating time or you. It will automatically
execute OPERATE commands every time when needed. The OPER button will be still unctional, so
youll be able to change to standby and back to operate manually at any time. A ter returning to operate
the irst time (by pressing OPER button again), the auto-operate eature will be restored.
In order to enable or disable the auto-operate at all, a ter a contrast and backlight 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 NEXT to select ON.
Press shortly the PREV+NEXT buttons again to accept and return.
N O T E
I LCD back-lighting or contrast are too low, thus no characters are seen on the
LCD, execute S.5-1 irst to obtain a readable display. All selections you make are
stored in the nonvolatile memory o the ampli ier and are used at the next power-
on. I no selection is made or 20 seconds, the currently existing selection is accepted
and the unction is le t automatically.
5-3. Reading Auto-protection Signatures
On every Hard Fault protection trip o the ampli ier, signature in ormation is stored in its nonvolatile
memory. The 7 most recent auto-protection trip signatures related to the ampli ier internal status are
stored there, which you can copy and orward to your dealer or diagnostics.
In order to read and to copy them press the OPER button while OFF LINE. The backlighting o the
LCD will light and youll see the beginning o the signatures list. Use NEXT and PREV buttons to
navigate through 7 pairs o screens. For each auto-protection trip there is a pair o in ormation screens,
beginning with nA... and nB... where:
- n is the number o the event (nr.1 is the last, nr.7 is the oldest one);
- A and B mark the irst and the second part o an in ormation screen pair.

17
Two lines, three groups by six symbols (36 symbols in total) are to be copied concerning every one o
the 7 memorized events rom 1A-1B through 7A-7B.
To decode the signatures please see S.6-5 (Troubleshooting).
N O T E
A ter every signature listing the tube warm-up time is reset to 150 seconds regardless
o the time being in OFF LINE state.
6. MAINTENANCE
I 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
o not use solvents for cleaning - they may be dangerous both for you and
for the amplifier paint or plastics.
Do not open the ampli ier. Cleaning o the ampli ier outer sur ace can be done with a piece o so t
cotton cloth lightly moistened with clean water.
6-2. Fuses Replacement
I it is necessary to replace the mains uses, use only standard ones.
The two Primary Mains Fuses o the ampli ier are located on the rear panel (Fig. 2-1). They are 10A/
250V Quick blow, 1-1/4 x 1/4 inch Cartridge Fuses, Size 0 Ceramic.
Besides the primary uses, on the MAINS PCB (inside the ampli ier) there are two more small glass
uses (5x20mm, 100mA and 2A slow-blow type) which are not replaced by the user. Should one o
these uses be blown, it may be indicative o other ailures. This is a complex and potentially dangerous
operation. For this reason, we recommend this work be carried out by a trained service technician.
6-3. Tube Replacement
A single 4CX800A (GU74B) high-per ormance ceramic-metal tetrode manu actured by Svetlana is
employed in the ampli ier. Replacement is a complex and potentially dangerous operation. For this
reason, we recommend this work be carried out by a trained service technician.
6-4. The ACOM1000 Simplified Schematic iagram
See Fig.6-1 ACOM1000 Simpli ied Schematic Diagram. * The 4CX800A (GU74B) Svetlana high
per ormance ceramic-metal tetrode (V1) with plate dissipation o 800W is grid-driven. The input signal
rom the RF INPUT jack is passed through a broadband input matching circuit, which comprises some
components in the INPUT PCB and Rsw. This circuit tunes out the input capacitance o the tube. The
swamping resistor Rsw is a termination load or this circuit and can dissipate up to 100W o RF drive
power.

18
Cathode resistor Rc creates DC and RF negative eedback, thus stabilizing the gain and equalizing the
requency response. The varistor VSsg in the screen grid circuit protects the tube screen grid, and
voltage regulator in the events o a lashover.
The combination Lp1-Rp1 in the plate circuit is a VHF/UHF parasitic suppressor. DC plate voltage is ed
through chokes RFC1-RFC2 and the capacitor Cb3 blocks it rom the output. The output circuit
comprises LP1, LP2, LL, CP1-CP3, and CL1-CL3 which orm a classic Pi-L network and suppress the
harmonic requency emissions. This tank is switched and tuned over the bands by S1A-S1C and the air
variable capacitors CP1, 2 and CL1, 2. The output signal is ed through an additional VHF low-pass ilter
or requencies above 55MHz (L 1, L 2 and C ). Then it is passed through the vacuum antenna relay K1,
wattmeter current trans ormer TA1, and a high-pass ilter RFC4-Ca or requencies below 100kHz, to
the antenna output. The chokes RFC3 and RFC4 keep track o the antenna relay contact conditions and
together with Ca prevent the plate supply rom reaching the antenna. RFC4 shunts it to ground i the
DC blocking capacitor Cb3 ails. The resistor Ra protects the ampli ier rom charging Electro-static
energy ed by the antenna.
The PLATE CAPACITIVE DIVIDER and RF WATTMETER are the main sources o in ormation or the
control circuit o the ampli ier during the antenna impedance matching process. The control circuit is
based on the 80C552 micro-controller rom Philips.
All voltages are delivered rom the MAINS&LOW VOLTAGE and HIGH VOLTAGE SUPPLY PCBs. The
control grid, screen grid and plate currents, plate cooling air low temperature, re lected power etc. are
permanently monitored. Many so tware-derived protections are based on this in ormation.
* Detailed electrical schematic diagrams are available rom ACOM or rom your dealer on request.
6-5. Troubleshooting
See S.5-3 or the method o reading the auto-protection signatures. You can decode them using the
in ormation below. *
The signatures are structured in two lines, three groups by six symbols or every one event o
auto-protection. The last event is numbered as 1A-1B pair o lines, and the oldest one is 7A-7B.
The meaning o the irst group is as ollows:
a) nA - the number o the trip;
b) Next three symbols mean the ollowing:
PN0 - tests made during Power-On procedure, be ore HV is ON;
PN2 - tests made during Power-On procedure, a ter HV is ON and 1 second a ter step-start is
closed;
SB0 - tests made in Stand-By, during the warm-up period or while entering Stand By ( rom Operate);
SB2 - tests made during Stand-By, a ter the warm-up period;
PR0 - tests made while entering Operate;
PR2 - tests made during Operate;
TR0 - antenna relay tests made while changing rom Tx to Rx (during Operate)

19
TR2 - antenna relay tests made while changing rom Rx to Tx (during Operate)
TR4 - antenna relay tests made during Tx (Operate mode)
TR6 - antenna relay tests made during Rx (Operate mode)
c) The last symbol o the irst group designates the kind o 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 orward power (p wd, analogue)
2 - re lected power (r l, 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 ault (ARCF, logic)
D - control grid current too high (G1C, logic)
E - +24VDC power supply error (PSE, logic)
F - low air low (LAIR, logic)
For instance, 1ATR4B in the irst group would mean that the last auto-protection (1A) tripped by the
antenna relay tests made during Tx - Operate mode (TR4), and the output relay closed - ORC signal
was ailing (B).
The next ive groups o symbols carry in ormation about the analogue and logic values as measured by
the micro-controller (at the moment o auto-protection trip).
* Additional in ormation is available rom ACOM or rom your dealer on how to interpret these values.
Using an EXCEL APPLICATION (available rom ACOM or your dealer ree o charge) and a PC, you
can decode these signatures easily by yoursel .
In case it is necessary to ship the ampli ier please see S.7-3.

20
7. SPECIFICATIONS
7-1. Parameters
a) Frequency Coverage: All amateur bands 1.8-54MHz, extensions and/or changes on request.
b) Power Output: 1000W PEP or continuous carrier, no mode limit.
In continuous carrier modes (RTTY etc.) or transmissions longer than 15 minutes (up to several hours
depending on ambient temperature), the external auxiliary an 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:
1.8-29.7MHz - better than 50dB below rated output,
50-54MHz - better than 66dB below rated output.
) Input and Output Impedances:
- Nominal value: 50 Ohm unbalanced, UHF (SO239) type connectors;
- Input circuit: broadband, VSWR less than 1.3:1, 1.8-54MHz continuously (no tunings, no switching);
- Bypass path VSWR less than 1.1:1, 1.8-54MHz continuously;
- Output (antenna) impedance matching capability: VSWR up to 3:1 or higher.
g) RF Gain: 12.5dB typically, requency response less than 1dB (50 to 60W drive power or rated
output).
h) Primary Power: 170-264V (200, 210, 220, 230 & 240V nominal taps (100, 110 & 120V taps on
request), +10% -15% tol.), 50-60Hz, single phase, 2200VA consumption at rated output.
i) Complies with CE sa ety and electromagnetic compatibility requirements as well as FCC-regulations
(10 & 12m bands lock provided).
l) Size & Weight (operating): W422mm x D355mm x H182mm, 22kg.
m) 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.