AMERITRON AL-572 Instruction Manual

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Ameritron AL-572

Introduction ................................................................................................................................. 1

Unpacking Instructions................................................................................................................ 2

Features ....................................................................................................................................... 3

AL-572 Technical Specifications ................................................................................................ 4

Input ................................................................................................................................ 4

Output.............................................................................................................................. 4

Efficiency ........................................................................................................................ 4

Power Supply .................................................................................................................. 4

Tube................................................................................................................................. 5

Metering .......................................................................................................................... 5

ALC ................................................................................................................................. 5

Relay................................................................................................................................ 5

Connectors....................................................................................................................... 5

Physical ........................................................................................................................... 5

General Information .................................................................................................................... 6

Safety Interlock ............................................................................................................... 6

Peak Envelope Power vs. Average Power....................................................................... 6

Circuit Descriptions..................................................................................................................... 7

ALC ................................................................................................................................. 7

Dynamic Bias .................................................................................................................. 7

Wattmeter Circuit............................................................................................................ 8

Power Supply .............................................................................................................................. 8

Filament Supply .............................................................................................................. 8

Plate (HV) Supply ........................................................................................................... 8

Meters.......................................................................................................................................... 8

Current Meter (plate and grid)......................................................................................... 8

Multimeter....................................................................................................................... 9

Multimeter Functions .......................................................................................... 9

Tube Life ..................................................................................................................................... 10

Export Modifications .................................................................................................................. 11

Technical Assistance ................................................................................................................... 12

Notes................................................................................................................................ 12

Installation Guidelines And Suggestions .................................................................................... 13

Location Of The Amplifier.............................................................................................. 13

Ventilation....................................................................................................................... 13

Power Connections.......................................................................................................... 13

Grounding........................................................................................................................ 14

Transformer Connections ................................................................................................ 15

Interconnections .......................................................................................................................... 16

HV ........................................................................................................... 9

REF.......................................................................................................... 9

ALC ......................................................................................................... 10

ALC SET................................................................................................. 10

Instruction Manual

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Page 1: Table Of Contents
Ameritron AL-572 Instruction Manual Table of Contents Introduction ..........................1 Unpacking Instructions........................ 2 Features ............................3 AL-572 Technical Specifications ....................4 Input ..........................4 Output..........................4 Efficiency ........................4 Power Supply ........................4 Tube..........................5 Metering .......................... 5 ALC ..........................5 Relay..........................
Page 2 AL-572 Tuned Input Chart....................29 Meter Board (50-0057-3) ....................29 Timer / Overload Board (50-0057-5) ................30 AL-572 Main Chassis Parts List ..................31 AL-572 Wiring Diagram ......................32 Power Supply / SWR Board Schematic ................33 Tuned Input Board Schematic..................34...
Page 3: Introduction
1300 watt PEP Linear Amplifier Instruction Manual NTRODUCTION The Ameritron AL-572 is a 1000 watt CW, 1300 watt PEP (nominal output power) linear amplifier that operates on all Amateur bands from 160 through 15 meters (WARC bands and ten meters with reduced performance). The AL-572X and AL-572Y are export models that operate from 160 through 10 meters.
Page 4: Unpacking Instructions
Save the screws to re-secure the cover. Carefully lift the rear of the cover while sliding the cover back. The AL-572 is shipped with the fuses and fuse caps packed inside the amplifier. Additional screws will be included in the fuse pack when required.
Page 5 Ameritron AL-572 Instruction Manual...
Page 6: Features
Logging scales allow quick and repeatable control adjustments for rapid band changes. The AL-572 has two illuminated cross-needle panel meters. The left meter provides a continuous reading of grid and plate currents. The right meter reads peak RF power output on one scale and Plate Voltage (HV), Reflected power and SWR (REF), ALC detector voltage (ALC), and ALC adjustment level (ALC SET) on the other scale.
Page 7: Al-572 Technical Specifications
Ameritron AL-572 Instruction Manual AL-572 TECHNICAL SPECIFICATIONS NPUT Circuit type:............... Pi-network, slug tuned coils Maximum VSWR at resonance:........ 1.3:1 or less Minimum 2:1 VSWR bandwidth: ......typically 15% of center frequency Maximum SSB drive power permissible: ....110 watts PEP Typical drive for full CW power output:....
Page 8: Tube
Ameritron AL-572 Instruction Manual Normal line current at rated CW output:....16 A at 120 Vac Normal line current at 1300 watt PEP output: ..8 A average at 120 Vac Power line current in standby:........2 A at 120 Vac Type:................
Page 9: General Information
7. NEVER make any unauthorized component or circuit modifications to this product. The only acceptable source for modifications is Ameritron or a source approved by Ameritron. Unauthorized modifications almost certainly will increase the risk of equipment failure or personal injury.
Page 10: Circuit Descriptions
Instruction Manual CIRCUIT DESCRIPTIONS The AL-572 is one of the few amplifiers using a "true" automatic level control (ALC) circuit. In this amplifier, the ALC actually samples grid current and power supply loading to determine the ALC voltage. The front panel "ALC SET" knob adjusts the level of grid current where ALC action begins.
Page 11: Wattmeter Circuit
ATTMETER IRCUIT The AL-572 wattmeter circuit uses an accurate directional coupler followed by a true peak detector circuit. This circuit will accurately determine the true peak envelope power (PEP) of normal voice waveforms. If the load SWR is high, the true power reading will be obtained by subtracting the reflected power from the forward power.
Page 12: Multimeter
Ameritron AL-572 Instruction Manual The left-hand meter scale indicates the grid current (Ig). The small pickets on this "Ig" scale appear every 10 mA and the larger pickets appear every 50 mA. The full scale "Ig" reading is 250 mA.
Page 13: Alc
In the AL-572, a grid current of 200 mA (at 100 watts of drive) produces rated grid dissipation. For maximum tube life, the short-term average grid current and drive power should always be...
Page 14: Export Modifications
125 mA of grid current and 70 watts of drive, is approximately ten watts. If you wish to add control grid protection to the AL-572, always remember fuses and resistors are too slow and unpredictable to adequately protect tubes. While grid protection is generally not required with tubes like the 572B, Ameritron does offer an optional fast-acting electronic circuit that will rapidly disable the amplifier if excessive grid current occurs.
Page 15: Technical Assistance
The packing materials used to ship this amplifier were specially designed to prevent shipping damage. The original packing materials should be used to ship this amplifier. Replacement packing materials may be purchased from Ameritron if original packing materials are unavailable or damaged.
Page 16: Installation Guidelines And Suggestions
600 watts of continuous carrier or 1300 watts of two tone power output when the amplifier is properly tuned. The fan in the AL-572 is a permanently lubricated type that requires no maintenance in normal operation. To insure adequate cooling in your installation, please observe the following: 1.
Page 17: Grounding
Ameritron AL-572 Instruction Manual For 120 volt operation, the wiring between the fuse box and the amplifier ac outlet must be number 14 gauge (or larger) in order to supply the current required (16 A) without a significant drop in the line voltage. The 120 volt outlet should be fused for 20 amperes.
Page 18: Transformer Connections
The high voltage secondary of the AL-572 has three leads. The normal wiring is indicated on the circuit board silk-screen by the initials R/Y (RED/YELLOW) and R/G (RED/GREEN). For low power operation the R/Y and R/G wire can be reversed.
Page 19: Interconnections
Instruction Manual NTERCONNECTIONS 1. Connect the exciter's RF output to the "RF IN" connector on the rear of the AL-572 with 50 ohm coax. Use any good quality 50 ohm cable long enough to connect the amplifier to the exciter. This amplifier connection uses a standard SO-239 female that mates with a PL-259 male connector on the cable.
Page 20: Plate" Control
DJUSTMENTS ALC Metering Functions The "MULTIMETER" switch in the AL-572 has two positions that indicate the functioning of the ALC circuit. These positions are as follows: In this position the multimeter measures the output voltage of the ALC detector. The full scale reading of the ALC detector voltage is 35 volts.
Page 21: Alc Set
Ameritron AL-572 Instruction Manual ALC SET In this position the multimeter measures the approximate grid current that will produce ALC activity. One zero must be added to the reading on the ALC/ HV scale for this function. For example: If the meter reads 15, add one zero (150). In this example ALC action will begin at approximately 150 mA of grid current.
Page 22: Rear-Panel "Alc Limit" Control
Ameritron AL-572 Instruction Manual should be adjusted until the ALC voltage meter slightly flickers (ALC position of the "MULTIMETER" switch) while operating with normal output power levels. The ALC circuit will limit the amplifier's grid current to a safe value if anything accidentally changes in the station or the antenna.
Page 23: Driving Power
A second method of determining linear operation is to monitor the peak RF output power carefully on the AL-572's internal meter. Determine the maximum obtainable RF output power and reduce the exciter's power until there is a noticeable margin from the maximum output power.
Page 24: Tuning
Ameritron AL-572 Instruction Manual UNING WARNING: The transformer must be wired correctly for your line voltage. This amplifier is normally shipped wired for standard operation. " RANSFORMER " section on page 15 for details. ONNECTIONS Important Note: If you have installed the optional electronic grid protection circuit to prevent control-grid damage, this amplifier will quit operating if the grid current exceeds a safe pre-set limit.
Page 25: Tuning Procedure
Please go through the following procedure carefully, in numerical order, until you develop a "feel" for operating and tuning this power amplifier. Once you are used to operating this amplifier, steps not marked with an asterisk (*) can be eliminated. 1. Set the AL-572 front panel switches as follows: POWER OPR-STBY...
Page 26 Ameritron AL-572 Instruction Manual 6. With the exciter's drive level still on zero, observe the 1000 mA Ip scale on the left hand meter. It should indicate zero (0) amperes. *7. Place the "STBY-OPR" switch in the "OPR" position. Place the exciter in the transmit mode with no RF output.
Page 27: Alc Set" Control
Ameritron AL-572 Instruction Manual *11b. Increase the exciter drive power (if the ALC is not connected) until 180 mA of grid current is indicated. Adjust the "LOAD" and "PLATE" controls for maximum RF output power. The grid current should not be allowed to go above 200 mA at this stage. The plate current should not be allowed to exceed 750 milliamperes except during brief periods (15 seconds or less).
Page 28: Additional Ssb Notes
Braiding or woven wire has a very high RF resistance and should be avoided. See the "G " section on page 14 of this manual. More detailed suggestions on grounding ROUNDING are available by requesting Ameritron's Tech Bulletin on RF Feedback.
Page 29: Fm (Frequency Modulation), Rtty, And Digital Operation
QSK-5 unit. The QSK-5 operates directly from 120 Vac power lines. Ameritron also offers an internal QSK board as a space-saver for the AL-572. This internal board is slightly less expensive. However, it provides less flexibility and serviceability than the external QSK-5 unit.
Page 30 7. NEVER make any unauthorized component or circuit modifications to this product. The only acceptable source for modifications is Ameritron or a source approved by Ameritron. Unauthorized modifications almost certainly will increase the risk of equipment failure or personal injury.
Page 31: Parts List
Ameritron AL-572 Instruction Manual PARTS LIST / SWR B (50-0057-1) OWER UPPLY OARD Designator Description Ameritron P/N D101,102,114,115 1N34A 300-0346 D103 1N757A Zener 9.1V 305-0757 D116-120 1N4001 300-0266 D104-113 1N5408 300-0145 C101 27 pF 500 V 208-5404 C102,105 .001 uF 1 kV...
Page 32: Tuned Input Board (50-0057-2)
Ameritron AL-572 Instruction Manual (50-0057-2) UNED NPUT OARD Designator Description Ameritron P/N C201 (transmitter side) See input chart C202 (tube side) See input chart C213-215 .01 1 kV disc capacitor RFC1 filament choke 30 ampere L201 See input chart S201...
Page 33: Timer / Overload Board (50-0057-5)
Ameritron AL-572 Instruction Manual (50-0057-5) IMER VERLOAD OARD Designator Description Ameritron P/N C501-506 .01 uF 50 V disc 200-0416 C507,508 .47 uF tantalum 203-0530 C509 100 uF 25 V 203-0564 D501, 502 1N4001 300-0266 D503 5.6 V zener 301-710 IC501...
Page 34: Al-572 Main Chassis Parts List
Ameritron AL-572 Instruction Manual AL-572 M HASSIS ARTS Designation Description Ameritron P/N 410-3138 C1-3 .001 uF 7.5 kV 200-7224 500 pF Doorknob 7.5 kV 210-0470 C5, 6 170 pF Doorknob 7.5 kV 209-0559 Air Variable Plate 250 pF 3.5kV 204-2112 Air Variable Load 800 pF 1.2 kV...

AMERITRON AL-572 Instruction Manual

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