DRAKE L7 Operator's Manual

' Fig. 1-1 Model L7 Linear Amplifier 6 .>- SPECIFICATIONS Frequency Coverage: Ham bands 160 through 15 meters. Non-amateur fre- quencies bet

WARNING The L 7 has been designed incorporating several interlocks to prevent dangerous electrical shock. However, it is possible to disconnect the hi

2-4. POWER REQUIREMENTS The L 7 is furnished with its own separate Power Supply which can be operated from either 120 VAC or 240 VAC 50-60 Hertz

2-12. VOX RELAY Aphono jack on therearoftheL7AmpMerkpm vided for connection to a paiT of norma& open relay contacts in the exciter, which doseon

TYPE ACCEPTANCE LABEL HIGH VOLTAGE CONNECTOR J5 . .. .. ~, . .. -. . .: - . - . . <;,i = I J6 -- . I ; : CONNECTOR I .I . ; L . , e; -. n '

120 VOLT OPERATION Amplifier Power Supply -- ~~ ~~ -- - Figure 2-2. Jumper Connections for 720 Volt Operation .+ - - . ... . ~ - .. 240 VOLT OPE

Fig. 2-4 Connecting the PS-7 Power Supply and the R. L. Drake Line of Compatible Exciters

OPTION A i OPTION B INVERTED FRONT FEET mi SUPPLIED WITH UNIT SUPPLIED WITH UNIT Fig. 2-5 Viewing Angle Options

.> NOTES

CHAPTER 3 OPERATION CAUTION DO NOT turn on the L 7 Amplifier with the cabinet removed because the high voltage inter-lock shorts out the B+ and will

- FIGURE 3-1. FRONT PANEL CONTROLS I. Multimeter: Indicates plate voltage, grid current, and forward or reflected watts as selected by meter switches

220 mA of grid current with the LOAD control until 0.565 plate Amperes is reached. Leave the exciter power at this level and redip the plate cur- re

instead of the 3000 Watt scale. When returning ..>-: the amplifier to service, be sure toreturn theMeter . : switch to 3000 Watts or the watt

1000 Watts D C. Input VS Plate Voltage and Plate Amperes 1900 . . .".' .. - -. . -. .. . . -. .. . 1800 . - -. PLATE VOLTAGE PIATE AMPERES .

NOTES

CHAPTER 4 4-1. INPUT Refer to the schematic diagrams figures 5-4 and 5-5. The 50 ohm input is matched to the final amplifier cathodes by a pi-network

NOTES

CHAPTER 5 MAINTENANCE 5-1. SERVICE DATA Your L 7 will be checked and aligned at the factory for a nominal fee if it has not been tampered with. Transp

b. 50 Ohm SWR Bridge c . Standard Milliammeter (400 mA) d. RF Wattmeter such as R. L. Drake Model WH 7 or an RF Voltmeter such as Hewlett-Packard Mode

m. Turn off the Amplifier, disconnect the Power Supply from the power source, replace the jumpers removed in step c above, remove the SWR bridge

OPERATOR'S MANUAL LINEAR AMPLIFIER

with the standard wattmeter or with the RF power calculated from the RF voltage mea- sured across the 50 Ohm load. 5-16. 3000 WATTS FORWARD a. Af

PARASITIC CHOKES RF PLATE CHCUE (PC-1, PC-2) (RFC-4) - \ GRID &RENT C42 CAL. POT. R-19 Fig. 5-1 Component Locations, Top View

I 120/22(1V mMINAL STRIP \ (SEE FIG 2-3) FILERS LOW PAS FILTER Fig. 5-2 Component Locations, Bottom View

1.5 VOLT 10n POT M TEST PT. A 0-400 MA MlLLlAMMETER R, L 7 CHASSIS PUSH BUTTON BOARD Fig. 5-3 Connections for Grid Current Meter Calibration RtJ TNmU

NOTES

NOTE Wpadtmlnarked1.Om2400arehpl.~d C.p.cltor.n*r*.d.W1to.l uahmfd-emr*rluraMd. Cornp~nsnt Locations . . 17 UNEAR AMP Schemrtic Dwg +D4788 Fig. 5-5 Mo

0 R. L. DRAKE COMPANY 1979 PRINTED IN U.S.A.

TABLE OF CONTENTS .. -~ . PAGE ... ... CHAPTER 1 INTRODUCTION , 1-1 ...

PAGE ... TUBE REPLACEMENT.. ... 5-1 ... TEST EQUIPMENT ... 5-1 AMPLIFIER TROUBL

LIST OF ILLUSTRATION'S Figure 1-1 2-1 Page -- i i . . MODEL L7 LINEAR AMPLIFIER ... 1-2 :'- .z. REAR CHASSIS

1-1. GENERAL DESCRIPTION TheR L. Drake Model L 7 Linear Amplifier offers con.tinuoas 2000 Watts PEP on SSB, and 1000 Watts DC on CW, AM (controlled