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Summary of Contents for Ehrhorn Technological Operations ALPHA 86
- Page 1 OPERATING & TECHNICAL MANUAL ALPHA 86 HE LINEAR POWER AMPLIFIER EHRHORN TECHNOLOGICAL OPERATIONS, IN C 4975 NORTH 30TH STREET COLORADO SPRINGS, CO 80919 COPYRIGH T 1990 BY E.T.O., INC.
- Page 2 OPERATING & TECHNICAL MANUAL ALPHA 86 HF LINEAR POWER AMPLIFIER NOTE ALPHA 86 The schematic diagrams and text in this manual describe the latest production version of the amplifier, including early units which have been factory-modified. Minor design changes (which do not affect overall circuit design, specifications, capabilities, or operat...
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Page 3: Table Of Contents
CONTENTS GENERAL Service Assistance Initial Inspection 10 and 12 Meter Operation SECTION 1 Introduction General Description Specifications SECTION 2 Preparation for Operation Transformer Installation Shipping Hardware Removal 120 Volt Modification Transformer Installation - Pictorial SECTION 3 Transceiver Connection Transceiver Connection - Pictorial SECTION Operation Control Functions... -
Page 4: General
(719) 260-1191. INITIAL INSPECTION OF YOUR ALPHA 86 When you remove the top cover to install the power transformer (see p. 5) make sure the tubes are firmly seated in their sockets and the tube anode connectors (silver strap rings) are firmly attached to the tube plate caps. -
Page 5: General Description
SECTION 1 - INTRODUCTION 1.1 General Description ALPHA 86 is a self-contained, HF linear power amplifier capable of continuous operation at a power output of 1500 watts PEP, keyed CW, SSTV, RTTY, or AM, with no time limit (rated for continuous commercial service, "CCS"). -
Page 6: Preparation For Operation
1.2.16 Power Transformer: Tape-wound Hipersil®core, 3.5 kVA CCS. 1.2.17 Protective Devices: primary and step-start fuses, primary AC interlock, high voltage crowbar, plate overcurrent trip, T/R mis-sequence trip, and reflected power trip. 1.2.18 Status Indicators: operate, standby, wait (initial tum-on time delay), overdrive (excessive grid current), SWR (reflected power tripout), and T/R fault. -
Page 7: Volt Modification
2.4 Primary Power -1 2 0 Volt Modification ALPHA 86 is factory set up for operation from a 220-240 volt source. It is fused at 20 amperes. A dedicated branch circuit to the amplifier, using #10 AWG copper wire or equivalent (with a current capacity ALPHA 86 of at least 30 amps) is recommended for best results. -
Page 8: Transformer Installation
FIGURE 1 ransform er nstallation Ï V I R E S O M IT TED FOR C L A R IT Y ORANGE BLACK... - Page 9 SECTION 3 - CONNECTION TO THE TRANSCEIVER ALPHA 86 interconnections to the station transceiver are shown in figures 2 and 3 on page 7. 3.1 Coax Types & Connectors ALPHA 86 Connect the transceiver RF output to the RF input with 50 ohm coaxial cable-type RG-58C/U...
- Page 10 FIGURES 2 & 3 onnection t o the ransceiver FIGURE 2. ALPHA 86 I n t e r c o n n e c t i o n s f o r Normal VOX, PTT, AND QSK Operation, TD ANT...
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Page 11: Switches
SECTION 4 - OPERATION 4.1 Tune-Up Control Functions BAND - Selects tuning range; scale indicates principal amateur band covered. Frequency ranges in MHz are displayed on commercial models. TUNE - Selects operating frequency. In general, higher frequency bands tune toward the"0" end of the dial scale, while lower bands tune toward the "50"... - Page 12 If reflected power is less than ten percent of forward power, the VSWR is lower than 2:1 and it is safe to proceed. Turning on the ALPHA 86 1) Select LO plate voltage (HI-LO switch).
- Page 13 7) Adjust TUNE control to deflect TUNE LED maximum left. 8) Adjust LOAD control to center the illuminated LED. 9) Repeat steps 7 and 8 above. ALPHA 86 10) Increase transceiver output until output is 1,000 watts. 11) Adjust TUNE to deflect TUNE LED maximum left.
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Page 14: Reflected Power Protection
While operating check the reflected power bargraph to ensure that it remains below 150 watts (equal to a 2:1 VSWR when the amplifier output is 1,500 watts). Variations in reflected power may indicate a problem ALPHA 86 in the feedline or the antenna. If reflected power exceeds approximately 200 watts the will imme... -
Page 15: Initial Control Settings - Table
29.00 29.60 Note: The settings above are a COMPOSITE based on average ALPHA 86 performance characteristics. The settings you observe may vary — this will not indicate a problem with your amplifier but rather normal tolerances. All factory testing is done with the amplifier tuned to 1500 watts output and terminated in a 50... - Page 16 However, never depend on the interlock switches alone for protection. W A R N I N G ! CONTACT WITH LETHAL VOLTAGES EXISTING INSIDE THE ALPHA 86 MAY RESULT IN SEVERE PERSONAL INJURY OR DEATH FROM ELECTROCUTION! ALWAYS DISCONNECT THE AC LINE CORD FROM ITS WALL OUTLET...
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Page 17: Panel Lamp Replacement
® < 8 > The exterior of the ALPHA 86 can be cleaned with Fantastik, Formula 409, or similar household liquid detergents. Do not use chemical solvents as these may severely damage the front panel plastic overlay and the cabinet finish. Never use abrasive cleaners or pads! 5.6 Front Panel Lamp Replacement... -
Page 18: Troubleshooting Tips
SECTION 6 - TROUBLESHOOTING TIPS A) Will not turn on: nothing happens when ON switch is depressed. 1) External AC wiring, fuse or circuit breaker open. 2) Amplifier cover not in place; cover safety interlock open. 3) Fuse F1-F4 open or missing. 4) Voltage dropping resistor R8 open. - Page 19 I) Receive signals disappear or are severely attenuated when switching from STBY to O PR 1) RELAY control cable from transceiver is shorted. 2) Transceiver locked in transmit. 3) Receive fuse open (see page 17, Receive Fuse Replacement). 4) Damaged receive PIN diode. ♦...
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Page 20: Receive Fuse Replacement
Receive Fuse Replacement The PIN diode T/R circuit board has a fuse which may blow in the event of a control or circuit fault. If the fuse opens received signals will be lost when the OPR (operate) switch is depressed. WARNING: THE AMPLIFIER M UST BE TURNED OFF AND THE POWER CORD MOVING THE TOP COVER AND ATTEMPTING FUSE REPLACEMENT! -
Page 21: Theory Of Operation
SECTION 7 - THEORY OF OPERATION 7.1 Power Supply and Control Refer to Figure 5. When the ON rocker switch is momentarily depressed (closed), the AC power control circuit is com pleted through contact 1 of P4, FI, the ON switch, S3 (normally dosed OFF switch), R4, S5, K14, K ll coil, F2, and contact 2 of P4. - Page 22 AC interlock S5 operates in conjunction with the HV crowbar. When the top cover is lifted approxi mately 1/4 inch, S5 opens, turning off all AC power. Lifting the cover further causes the HV crow-bar to discharge the filter capacitor bank. Cutoff bias from the 36 volt supply is applied to the tube cathodes via R17.
- Page 23 The tap on plate shunt feed choke L2 is selected by K4 to provide efficient operation over the full frequency range. Additional HV decoupling is provided by R3, C12, C16, C17,L8, C13, C14, and C15. RF from the tube plates is coupled to the output network via DC blocking capacitors CIO and C ll. The nominal 50 ohm load is transformed to an appropriate plate load resistance by the bandswitched pi-L network.
- Page 24 7.5 Function Control/ALGTune Refer to schematic Figures 9,10, and 11. Basic amplifier function control is straightforward. Two logic inputs must agree before the amplifier can be switched into the transmit mode. 1) The three minute time delay must be completed. 2) No RF may be present at the RF input detector;...
- Page 25 R e fer to F ig u re 11 ALC is derived as a function o f am plifier grid current. A grid current sam ple from R24 is amplified and inverted by U 5C/D. The negative-going output is available for control of transceiver R F peak output. The TUN E meter d rcu itry determ ines am plifier gain by com paring detected R F voltages at the cathodes and plates of the 3C X800A7 power tubes.
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Page 26: Schematics
» notes A L L S W I T C H E S SH O W N F U L L C L O C K W I S E P O S IT IO N . C A P A C IT O R V A L U E S A R E p F W HOLE N U M B E R S AND u F D E C IM A L N U M BERS, JOS. - Page 27 NOTE« ALL DECIMAL CAPACITANCE VALUES ARE IN uFj DISC CERAMIC D8“ 11=1N270 R l-1 4 = 2 2 0 K / 2 V C l -7 = 3 5 0 u F / 4 5 0 V J 3 PINS AS V IEW ED PIN # FRDM TOP DF BOARD H V S V...
- Page 28 220K 220K < < 220K > > 220K > — j► — ) £ £ 220K > > 220K » — < ► — 1 £ £ 220K > > 220K « — i r - ^ L — 1 R ll 220K S S 220K...
- Page 29 PIN FUNCTIONS ft, ORDER AS V IE W ED FROM TOP OF BOARD WIRE COLORS AS MARKED D1-D4 1N5401 D5&D6 1N4004 FIGURE 8 oltage ower upply...
- Page 30 I L A M P I >- T -------1 i (----- t-------1 2 J----- I > + 1B V ♦MV 1 -------- 4 J ‘ C l l 10uF/2BV r - — £ i j----- T A N T 1 -------4 2 REV_IH "...
- Page 31 +sev < Z O FIGURE 10 o n tro l o a rd heet...
- Page 32 + 1SV . 0 luF 1N414S R 4 C 100K 2. 2 / T A N T -15V E 5 0 vi+Am- . 0 luF FIGURE 11 o n tro l oard heet...
- Page 33 RF OUTPUT RF INPUT w.w:»; . 1UF FIGURE 12 oard...
- Page 34 K3-> SVR FAULT SWR FAULT <TR FAULT ♦28 ♦ee U7-MC1401I US-MCI *011 □ P I I 1 1 L D U9-MCI4001 ■A L L CAPACITORS OF DECIM AL VALUE ARC 50 VOLT M ONOLITHIC STBV«^ ^*HI U10-MCI4066 FRONT PANEL WITCHES ^ FIGURE 13 isplay oard...
- Page 35 N O T E S « 1 . lO M P O S IT IO N A V A IL A B L E O N E X P O R T M O D E L O N L Y . CIO ? 1000 1000...
- Page 36 50 OHM 120pF r ° 39pF r i b r i b j — o Ô À 25 OHM O lO +28V FIGURE 14 nput atching etwork...
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