National Radio NCL 2000, Manual

Page 1: ...R 11 00g Z 444elelo p i poe I 4 ei r irte e Nor 37 WASHINGTON STREET MELROSE MASSACHUSETTS NCL 2000 LINEAR POWER AMPLIFIER NICL 2000 el I 00 00...

Page 2: ...any Inc within ten days from date of purchase in order to validate the guarantee Naturally this guarantee does not extend to any product L M11 which has been subjected to misuse neglect accident impro...

Page 3: ...or use with transce vers such as the NCX 3 or separa e transmitter receiver combinations The antenna is automcHcally switched to the exciter when plate voltage is removed providing instant choice of n...

Page 4: ...with relative exciter power indicated on amplifier multi meter 15 Safety Provisions Primary power fuses one minute time delay plate current overload one ampere hinged cover utilizes Dzus fasteners wit...

Page 5: ...40 SSB CW se5 4 0 1 VDC PLATE M A METER 3 4 9 ON 1445 BULB PLI 6 6 C20 5 FIL 5 FIL I 01 METER LIGHTS TWO 1826 BULBS PL4 PL5 6 4 R17 Clfl 2W K4 12N0757 60 SEC DELAY READY I445BULB PL 2 K2 1 2 AMR PLATE...

Page 6: ...ection SECTION 3 OPERATION 8 3 1 Explanation of Controls 3 2 Preliminary Adjustment 3 3 CW Tune Up Procedure 3 4 SSB Tune Up Procedure 3 5 AM Tune Up Procedure SECTION 4 THEORY OF OPERATION 12 4 1 Cla...

Page 7: ...ay by an external switch The internal antenna transfer relay of the NCL 2000 utilizes aseparate pair of contacts to automatically bias off the output tubes when the amplifier is in the standby mode to...

Page 8: ...2 2 UNPACKING AND TUBE INSTALLATION Carefully unpack the NCL 2000 its plugs tubes and chimneys setting aside all packing mat erial for possible future use Lift the lid by turn ing the fasteners count...

Page 9: ...xisting jumper and wire new jumpers and the new cable as shown in Figure 1or as shown in the diagram on the compartment cover 115 VAC T 230 VAC NEUTRAL PRIMARY 2 4 ANTENNA CONNECTION The antenna to be...

Page 10: ...e identical to that described in para graph 2 8 2 10 RF EXCITER CONNECTION Separate Transmitter and Receiver Without External Antenna Transfer Relay See figure 4 The NCL 2000 has been equipped with as...

Page 11: ...TRANSMIT TRANSMITTER RECEIVER EXT ANTENNA RELAY ACTUATED BY TRANSMITTER CONNECTIONS FOR USE WITH A SEPARATE TRANSMITTER AND RECEIVER USING AN EXTERNAL ANTENNA RELAY e ANTENNA ycyR mift rm GNOALCQ 0 0...

Page 12: ...mum independent adjustment of the exciter without the usual necessity for a sep arate dummy load or the alternative procedure of attempting to simultaneously adjust both the amp lifier and the exciter...

Page 13: ...raph 10 above 2 The exciter whether transceiver or trans mitter receiver combination should now operate conventionally as a low power station when either the NCL 2000 pri mary power or plate power swi...

Page 14: ...e exciter to the transmit mode and increase drive while monitoring screen current to the point where further drive from the exciter does not result in an in crease in plate current Adjust PA TUNE and...

Page 15: ...tual peak grid current will be excessive and flat topping and consequent splatter will oc cur CAUTION YOUR NCL 2000 IS A MAXIMUM KILO WATT IN EVERY SENSE OF THE WORD UNDER THE ABOVE CONDITIONS YOUR PO...

Page 16: ...e important advantage of higher efficiency than the Class AB1 amplifier However the pre sence of the necessary well regulated bias supply presents the same disadvantage apparent in the Class B amplifi...

Page 17: ...voltage for use as ALC information This may be fed back by means of output jack J5 to exciters provided with ALC input circuits capable of accepting neg ative ALC voltage 4 5 OUTPUT CIRCUIT The plate...

Page 18: ...watts 550 ma at 1800 v and the load impedance will be properly matched because of the lower plate voltage and current The ef ficiency will now be back to 60 minimum and output will be in excess of 60...

Page 19: ...contain tubes on which a matching number has been written in which case it is only necessary to provide National with this number instead of R 33 R 34 T I L I T 2 M I PL 4 LID INTERLOCK FIGURE 6 SERV...

Page 20: ...1 tor remove the cabinet and the right side gusset unsolder the wires to the base and emitter pins and remove the screws that hold the transistor to the chassis This will also free the collector case...

Page 21: ...R20 15S 2 Zero Do NOT attempt to energize plate and screen supplies with the cabinet lid open Junction of C22 and L5 35 FIGURE 8 SECTION 6 TROUBLE SHOOTING CAUTION VOLTAGES USED IN THE NCL 2000 ARE LE...

Page 22: ...expanding which changes the internal geometry of the tube a In many instances antenna loads will be presented to the NCL 2000 which are outside the 40 to 60 ohm range of the pi network Antennas prese...

Page 23: ...ater Choke Swinging 6 H at 35 ma 3H at 70 ma 1500 v insulation 1501 d c resistance Choke RF Plate 165 R H 800 ma d c Choke RF 2 5 mH National Radio Catalog Number R100S 2 5 Coil Final Tank Choke RF 75...

Page 24: ...h relative exciter power indicated on amplifier multi meter 15 Safety Provisions Primary power fuses one minute time delay relay plate current overload 1 2 ampere relay hinged cover utilizes Dzus fast...

Page 25: ...e 01 I 39 IW 2510 45V 01 2N1109 1 001 02 2N1lee 0 00 12 11 I CI4 01 R40 220 R41 1 2 K BIAS ADJUST C1 1 171 01 X d IN1777 R42 IK IW CIO 001 C4 1 1 1 01 I CIS C11 R15 20 5 I NAA I 1 1 S3 MODE SWITCH SSO...

Page 26: ...4 7 2 h H V INTERLOCK _L RA TUNE BACK S5B C52 Opt 1000 V C47 C46 450pf 75 0 1 5KV 5KV C43 25 775_ pf FRONT SSA BAND SWITCH NOTE C45 100 pf 5KV S5 RA LOAD C42 B 0 15 1650 L I ALL RESISTORS IN OHMS 1 2...

Page 27: ...C I KI ANTENNA RELAY 17 BIAS CHECK 0 Je POWER TERMINAL BLOCK RIO HT END C5I I 01 FI 12 A 250V e 1 C2 1 01 F2 I2A 250V 71 C19 CR II 01 IN462 Z CRIO IN462 t RIGHT ENO Wt t euNNeNt INN C 1 01 BLI I POWM...

Page 28: ...as been found that in some installations switching transients ex ceed the Ply ratings of the screen diodes It is therefore recommended that 01uf 1KV special AC rating disc capacitors National part A51...

Page 29: ...122 it is essential that both tubes be returned to the factory This is to assure that correct matched replacements are returned to our customers 8122 tube pullers are available free of charge through...

Page 30: ...c suppressor failure due to ex tended key down use on 10 meters Construct new heavy duty choke as shown below r LoSe AS ou rs p Dififrien Zoo P ohm 2 watt centrally out para of bias o fos 6L e er reiA...

Page 31: ...00V 4 to K2 R34 R34 Replace if necessary and re 2500V AFTER R33 to K2 The new lead between R 33 and R 34 should be 10kv test wire To extend the black wire to the opposite end of R 34 splice in 4 1 2 p...