FT-401B_serv维修手册含电器原理图

CW OPERATIONUIsing the two contact jack supplied with the accessorypack.connect key as shown in the illustration.Most relaytype automatic keyers can be connected into the transcei-VOLTAGE AND RESISTANCEver for break-in operation without modification.bulMEASUREMENTSwhen using reed relay or Iransistorized automatickeyers place 390 ohm resistor in series with keyThe table lists voltages and resistance at all tubesockets.These values are measured with a VTVM withline.all tuhes installed in their respective sockets.TUNING PROCEDURE CWAll measurements should be made from socket pinsSet up transceiver as described in transmitter tuningto ground.with adjusting CARRIER control lo desired power out-Adjust transistor voltage regulator to exactly 9 voltsput up to maximumwith VR-202 on the printed board.Measure voltage atAfter completion of final tuning,install key jack in rearjunction of R294 and R295.apron of transceiver.Set MODE switch to Cw andVOX-GAIN switch to MOX.The transceiver is now setup for manual Cw operation.After completing a trans-mission the VOX-GAIN switch must be returned toSTBY position for receive operation.For break-in opera-tion.simply advance VOX-GAIN control.SIDETONE ADJUSTMENTTRANSMITTER ALIGNMENTCw sidetone level may be adjusted by rotating the1.Disconnect the high voltage (600 volts)by unsolder-tone level potentiometer (VR 203)located on the maincircuit hoard under the top cover.NOTF:Do not disturbing the lead at rectifier,and also the screen voltageby unsoldcring the conncction at pin 3 of the twosetting of adjacent paint marked controls.tube sockets.(V5.V6)2.Connect VTVM RF probe to pin 5 of V5.3.Set the MODE switch to USB or LSB,and theSERVICE INSTRUCTIONSVOX GAIN switch to MOX position.Adjust car-rier balance potentiometer VR 201 on the mainWARNINGprint board for minimum VTVM indication.Dangerous voltages are present,therefore extremecare is essential.Be sure that all power is disconnected4.Advance MIC GAIN control two positions,and turnthe MODE switch to CW/TUNE.hefore working on the chassis.Check the high voltagesin the capacitors by shorting the high voltage line to5.Adjust PRESEL control for maximum VTVM read-ground with an insulared serew driver.The transceivering.has bcen aligned and calibrated at the factory with proper6.Adjust the MIC GAIN control during transmittertest instruments and should not require realignment.alignment to keep VI'VM reading at 15 volts to avoidService or replacement of a major component may re-saturation of the circuits.quire subsequent realignment.but do not attempt tomake an alignment unlexs the operation of the transceiver7.Start with upper slug of T203 nearly out and peakis fully understood.for peak VTVM reading.8.Start with both slugs of 1204 nearly out and adjustboth slugs for peak VTVM reading.9.Set the BAND switch to the 80 meter band,the maintuning dial to the center (250 KHz),and the PRESELcontrol at center.Adjust the slugs of L901 L100ITEST EQUIPMENT REQUIREDfor peak VTVM reading.Adjus