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TRANSMITTER TROUBLESHOOTING GUIDE
L T
j o v 4 C
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5 0
j k F
Refer to the 'Transmitter Block Diagram" (fold-out from
Page 268). which shows how signals flow through the
Y H : ~ E
transmitter circuits, as you go through the tests on
the
7 0
following pages. Each circuit board is outlined with a dashed
pTOEfNTT
line, and the circuit functions are shown as solid blocks
* . - -
inside the outlines.
This troubleshooting guide is divided into the following four
TO IMP~DANCE
HIGH
INPUT VOLTMC~ER
sections: "Carrier GeneratorICrystal filter,"
"Transmitter
C H A S S I S
il M E G O H M
O R
HIGHERI
'
IF," "Driver," and "Power Amplifier." When you get the
DC I N P U T .
correct result for a test, proceed to the next one. I4 you do
not get the correct result, the last step will direct you to the
proper part of the "Maintenance" section and will call your
2. CONNECT VOLTMETER
I
attention to some specific areas to check. When you turn to
C O M M O N LEAD TO C H A S S I S .
me "Maintenance" section:
1.
Refer
to
any
applicable
parts
of
tJw
Figure 4-2
"Troubleshooting Chart."
2.
Refer
the
Chart" and check the
To u ,
the RF detector, connect
it
as shown in Figure 4-2.
"' I tages
in your
Transceiver
at
the
areas
DO NOT permit the terminal strip lugs t o touch anything
mentioned in
the
last step. (Also see "Voltage
while the detector is in use. The assembled terminal strip
and Continuity Checks," Page 272).
--
/ / C OW~~
yra?.&Afh~ap~e_@
.
insulate
.
--
it:
- { : !
i
I
3.
Check any questionable diodes and transistors,
See Page 274.
4.
6e a r e each circuit is correctly wired and that
CARRIER GENERATORlCR'fSTAL FILTER
me correct parts are installed.
5.
~~~d the
"circuit
~
~
~
~
~
i
~
t
i
~
~
*
~
and study the
(
)
Connect a dummy load capable of dissipating 100
Schematic to better understand and analyze
watts to the ANT socket on the rear panel.
your problem.
(
I
Set the BAND switch t o 3.5.
TEST CIRCUIT PREPARATION
( ) Set the rear panel slide switch to COM.
When a transmitter circuit board i s functioning properly, an
RF signal will be present at the output and input. Parts are
'
)
lurn
the LEVEL
fully
furnished for a simple RF detector which can be used with a
high input impedance voltmeter for signal tracing in-some
( )
Depress the PWR. TUNE, and ON buttons. All ofher
low level RF circuits. See Figure 4-1 and the accompanying
buttons should be released.
steps on the fold.out from Page 269.
k '
Refer to Figure 4-2 and connect the RF detector wires as
CAUTIONS:
follows:
I
DO NOT use the detector on circuits Containing more
( )
Red wire to the high input impedance voltmeter.
than 30 VAC or 30 VRF.
O L B U ~ E
(
1
Btaek
wire to the chassis of the Transceiver.
DO NOT use the detector on the PA circuit board or
i t s
output.
( )
Gray wire to pin 6 of board
E.
I
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Table of Contents
Troubleshooting
