1. Manuals
  2. Brands
  3. EHRHORN Manuals
  4. Amplifier
  5. Alpha 5841
  6. Manual

EHRHORN Alpha 5841 Manual

Hide thumbs
Table of Contents

Advertisement

Quick Links

Download this manual
Ehrhorn Technotogical Operations, Inc.
4975 North 30th Street
Colorado Springs, C O 80919
OPERATING AND TECHNICAL MANUAL
HIGH FREQUENCY LINEAR POWER AMPLIFIERS
MODELS PA-76, PA-76P, and PA-76C
EHRHORN TECHNOLOGICAL OPERATIONS, INC.
Revised May 1, 1977

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the Alpha 5841 and is the answer not in the manual?

Questions and answers

Related Manuals for EHRHORN Alpha 5841

Summary of Contents for EHRHORN Alpha 5841

  • Page 1 Ehrhorn Technotogical Operations, Inc. 4975 North 30th Street Colorado Springs, C O 80919 OPERATING AND TECHNICAL MANUAL HIGH FREQUENCY LINEAR POWER AMPLIFIERS MODELS PA-76, PA-76P, and PA-76C EHRHORN TECHNOLOGICAL OPERATIONS, INC. Revised May 1, 1977...
  • Page 2 Top View Showing Major Component Locations . 14 Schematic Diagram ...... Front Panel V i e w ....Front Cover SECTION 6 - STANDARD ELECTRICAL PARTS ....16 ET0/"ALPHA" PRODUCTS WARRANTY ....Back Cover EHRHORN TECHNOLOGICAL OPERATIONS, INC. CANON CITY, COLORADO 81212 5/77 U.S.A.
  • Page 3 SECTION 1 GENERAL DESCRIPTION The ALPHA 76 (model PA-76) is a self-contained high frequency lin­ ear power amplifier capable of continuous operation at d-c plate power inputs of 2.5 kilowatts PEP for SSB voice and one kilowatt average or continuous carrier with no time limit (NTL). The ALPHA 76 is tunable over the range 1.8-2.0 MHz plus 3_3°...
  • Page 4 SECTION 2 INSTALLATION Unpacking: Carefully remove amplifier and transformer from car­ tons; SAVE ALL PACKING MATERIAL FOR RE-USE - SHIPMENT OF THE ALPHA 76 IN OTHER THAN FACTORY PACKING MAY RESULT IN DAMAGE NOT COVERED UNDER WARRANTY. Inspect closely for evidence of shipping damage; if any is found, notify delivering carrier and seller at once.

  • Page 5: High Voltage Tap Selection

    PINS OR CONNECTOR IS AIMOST CERTAIN TO RESULT. On request, ETO will supply at no charge extra push-in pins with short leads attached. Once the amplifier is changed over for 110- volt operation, it is strongly urged that a conspicuous label or tag be attached to the power cable to avoid accidental 220-250 connection to...

  • Page 6: Section 3 • Operation

    6. RF And Control Connections : Interconnection of the ALPHA 76 for operation with any popular transceiver or exciter is extremely simple. Connect the rear panel jacks as follows: RF INPUT - Use a standard "RCA" type plug and RG-58C/U or similar small ohm coaxial cable to connect to transceiver or exciter "rf output”...
  • Page 7 SECTION 3 OPERATION 1. Control Functions: BAND - Selects tuning range of amplifier, indicating the nominal center of the range in MHz. TUNE - Controls amplifier resonant frequency. In general, higher frequency bands (28 & 21 MHz, etc.) tune nearer to the ”0" end of the vernier dial scale, while lower-frequency bands (3*5 and 1.8 MHz) tune more in the 50 to 100 range.

  • Page 8: Initial Tune-Up

    If the drive power is increased beyond the tune-up level after the final TUNE/LOAD adjustments, flattopping and un­ desirable distortion (on SSB) will result, along with grid current greatly in excess of normal. If drive power is reduced below the tune-up level without fur­ ther adjustment of TUNE and LOAD controls, amplifier efficiency will be reduced.
  • Page 9 (4) Very slowly increase exciter carrier output until the amplifier panel meter indicates plate current of 0.5 amps (1/3 scale). Press FWD button and carefully ad­ just LOAD control for maximum meter indication. Then adjust TUNE for maximum meter reading, and repeat the process of alternately adjusting first LOAD, then TUNE, until no further increase in FWD power is obtainable.
  • Page 10 (e) TUNE-UP UNDER "HV" CONDITIONS - When the optional HV tap change relay is not included, the ALPHA 76 may safely " b e tuned-up with maximum plate voltage applied so that the in­ ternal taps need not be changed. Extra care must be exercised, to avoid abusing the amplifier or tubes, to insure that (a) drive power is kept low and adjusted very carefully, with LOAD...

  • Page 11: Operating Notes

    4. Operating Notes: (a) TUBES - The 8874 ceramic triodes are extremely rugged and normally operate with a large margin of safety. They will deliver outstanding service life IF not damaged by grossly excessive grid dissipation or airflow blockage (keep the intake and exhaust vent areas clear!) Do not allow average plate current per tube to exceed 0.35 amp for more than 30 seconds, nor ever to exceed 0.5 amp.

  • Page 12: Troubleshooting Hints

    -10- TABLE II -- TROUBLESHOOTING HINTS POSSIBLE CAUSE/CURE SYMPTOMS External a-c wire, fuse, or 1. Won't turn on; nothing hap­ breaker open or missing. pens when ON toggle lifted. Cover a-c interlock open. Fuse FI or F2 blown or missing Step-start relay K2 not clos­...
  • Page 13 SECTION 4 THEORY OF OPERATION RF Amplifier Section: Tubes VI and V2 (and V in models P and C) are parallel-connected in a grounded grid configuration. +28 volts of cathode bias is applied via R7 and L7 to cut off plate current during non-transmit periods;...
  • Page 14 FWCT rectifier D13-D14, and filter capacitor C7, provide for bias and control circuitry. A 25 VAC transformer winding is "bucking” connected to provide approximately 95 VAC for the blower, resulting in a reduced noise level but virtually the same air delivery as at full voltage. Dual primary windings on T1 permit connection for either 125 V or 220-250 V operation, as described in the Installation section of this manual.

  • Page 15: Section 5 - Illustrations

    SECTION S — ILLUSTRATIONS FIGURE 1 - Transformer Installation or Removal...
  • Page 16 -1k- FIC-URE 3 - Top View Showing Ma.ior Component Locations 1 K1-K2-K3 UNDERNEATH...
  • Page 17 — JJjjE l*M C T E t ALL e U T l "< NOTES: ONLf OPTIONAL MV RELAY (K3> R 2 2 - 5 E A C H 4 7 0 /2 w :F A -? fc 9. ALL IN 4 0 0 4 U N L E i A -7 6 C J P 0 N L r (V CKTY) XFMR...
  • Page 18 I- » m V m e t e r s w it ALL BUTTONS, SHOV* EHRHORN TECHNOLOGICAL OPERATIONS, INC. N 4 0 0 4 UNLESS NOTED Canon City, Colorado MODELS P A -7 6 76C & 76P a n o...
  • Page 19 -16- STANDARD ELECTRICAL PARTS SECTION 6 SYMBOL SYMBOL DESCRIPTION DESCRIPTION Howard #3-90-8507 24V form A reed, Cl - C6 180uf/450V elect.; EAC #1A24AH CDE #FAH-l80-450 5V form A reed, 500uf/50V elect. EAC #1A5AH 15uf/20V tantalum .002uf/l KV disc 15uhy/lA rfc L5,L6,L7 0 9 f 0 1 9 t C10-C14,...
  • Page 20 ETO/"ALPHA" PRODUCTS WARRANTY EHRHORN TECHNOLOGICAL OPERATIONS, INC.(ETO) WARRANTS AS FOLLOWS EACH NEW ELECTRONIC PRODUCT OF ITS MANUFACTURE: (1) Workmanship and all components except rf power tubes are guaranteed for EIGHTEEN MONTHS (VOMAX only, twelve months) from date of original purchase if used exclusively in licensed amateur radio service, and for ninety days if used in non-amateur service.

Table of Contents