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NOTE: This is the screwdriver adjustmenton the top side of the chassis immediately behind the
panel and adjacent to the VFO enclosure and the 6AQ5 tube. (See Pictorial 9.)
CAUTION: BEFORE APPLYING POWER TO THE TRANSMITTER, IT SHOULD BE NOTED
THAT LETHAL VOLTAGES ARE PRESENT BOTH ABOVE AND BELOW THE CHASSIS. CARE
SHOULD BE EXERCISED NOT TO TOUCH ANY HIGH VOLTAGE POINTS WITH YOUR HANDS.
WELL INSULATED TOOLS SHOULD BE USED FOR BEHIND THE PANEL ADJUSTMENTS.
NOTE: At this point, the scale on the meter should be studied carefully to determine just how
the meter reads for the various positions of the meter switch. First note that the meter has two
scales; one from 0 to 50 and one from 0 to 10. The scales should be intergreted as follows:
METER SWITCH POSITION
MEASURES
RANGE OF READING
Driver
Driver plate current
0-50 ma
Grid
Final amplifier grid current
0-10 ma
Plate
Final amplifier plate current
0-500 ma
Volts
Final amplifier plate voltage
0-1000 volte
MOD.
Modulator plate current
1
0.500 ma
{ ) Insert fuses and plug transmitter into a 115 voll AC oullet.
(Turn the power switch to ON and check to be sure that all the tubes light up. Switch the
power off and recheck your wiring if any overheating is observed.
() If nothing unusual is observed under these conditions, advance the driver control (small red
knob centered in XTAL-VFO switch) slightly. Then adjust the DRIVER tuning control for a
peak reading. CAUTION: Do not hold the reading above 6 ma for morethan an instant. See
ifat least 6 ma is available through adjustment of the DRIVE control with the DRIVER tuning
peaked. Leave grid drive set to 5 ma. Note position of grid DRIVEcontrol knob with 5 ma
on the meter so you can return to this setting later. This indicates proper functioning of
crystal oscillator and driver stages.
{
) Move
the XTAL-VFO
switch to VFO and peak the VFO FREQUENCY knob until a maximum
reading is obtained on the meter.
Increase or decrease
the grid DRIVE te maintain the 5
ma reading. The VFO frequency dial indication is not significant at this time. VFO cal-
ibration will be accomplished later.
If at least 6 ma of drive can be obtained,
it indicates
that the VFO is working also.
( ) To test the final amplifier, return the grid DRIVE control to full counterclockwise position,
reducing thedrive to zero.
Move the meter switch to PLATE
and the PLATE
switch to ON.
Turn this switch off immediately incase of any arc, apparent overload or an excessive meter
reading {over 300 milliamperes). Normally the meter should not read or should read only
slightly up-scale,
ad; y
() Move the XTAL-VFOswitch to one of the unused crystal positions Rad
ene bnsteon-
tro} behind the panel until the meter reading just returns to zero. Then return the XTAL-
VFO switch to the VFO position.
() With the meter still in the PLATE position, adjust the grid DRIVE contro! withone handand
AMPLIFIER tuning with the other. Advance the drive slowly while simultaneously tuning
the amplifier for minimum on the meter, until the grid DRIVE control knob is positionedas
it was previously for § ma drive level. CAUTION: Do not let the amplifier plate current
exceed 300 ma under any circumstances, With the plate current dipped to minimum by the
amplifier tuning, return the meter switch to GRID and set the grid drive to § ma. Switch
back to PLATE and dip the AMPLIFIER tuning again. The final plate current should now
read in the lower portion of the meter scale.
Page 51
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