is correct. If the idle plate current is other than
60 mA, adj ust the BIAS control for 60 mA.
There is a l ittle d i fference in the idle cu rrent between
AC and DC operation. Adj ust the idle current to 60
mA for each operation.
1 1 . POWE R O UTPUT M ETE R ADJ UST M E N T
VR6. located o n the transceiver rear panel adjacent
to the antenna coax fitting. provides an adj ust.ment for
power output indication on the meter.
This potentiometer should be adj usted to ind icate 1/ 2
to 2/3 fu l l scale meter deflection w hen the transmitter
is producing ful l output power in the tune position.
It should be noted that the meter indicates relative
power output and is not the basis for determ ining
actual power output.
VR6 has been preset at the factory to read 1/2 to
2/3 ful l scale into a 5 2 ohm dummy load. The operator
should not indiscriminately adj ust VR6 into an unknow n
load or an antenna with h igh VSW R .
1 2. F I NA L AM P L I F I E R N E UT R A L I ZAT I O N
When replacing the final ampl ifier tu bes. i t may be
necessary to rese
t
the bias to give correct idle current
and check neutralization. Using the procedure outline
below will guarantee max imum output and long tube
life.
CAUT I ON
HIGH VOLT AGES A R E PRESENT ON U N DER·
SIDE OF CHASSIS A N D INSIDE OF FINAL
COMPARTMENT. USE GREAT CARE W H ILE
MAKING ADJUSTMENTS WITH WIRING EX·
POSED.
( 1 ) Connect a dummy load to antenna. and set meter
to IC.
( 2 ) Locate TC27 the neutral ization variable capacitor
shaft on the u nderside of the chassis near the
d river stage band sw itch wafer. in the final ampl i
fier section.
( 3 ) Check final amplifier idle current in USB or LSB
position and adj ust as described before.
( 4 )
Tune up the transceiver at 29 M Hz.
1 0 8
or lOC
band w ith MODE sw itch at TUNE position. and
advance the C A R R I E R control u ntil, m eter IC reads
200mA.
( 5 ) Rotate PLATE tun ing control and observ e dip as
indicated on the meter. I f the d i p i s not pro m inen t.
reduce the load ing control s l ightly for better indi
cation. A s the PLATE control i s rotated the meter
shou ld rise equally and smoothly on either side of
max imum dip ind ication.
( 6 ) Determine w h ich side of the dip rises abruptly.
Set PLATE control slightly to th is side of dip
keeping the meter read ing below
1 0 0
m A .
( 7 ) Using nonmetallic tuning w a n d . rotate neutral iza
tion capacitor shaft very slightly in the d irection
w h ich reduces the cu rrent show n on the meter.
Repeat steps 6 and 7 u ntil the meter indicates a
smooth and equal rise on either side of the maxi
mum dip point.
The final compartment cover must be in place to supply
the RF shielding required during the neutral ization
procedu re.
FINAL AMPLIFIER COMPARTMENT
--
2 4
-
