Motorola MSF 5000 Instruction Manual page 192

Chapter4
Alignment
MSF
5000
Instruction Manual
Alignment Procedures
OPERATE
4-26
a4
C
©
I-F
AGC THRESHOLD CONTROL
POTENTIOMETER
3"
mass
vuone)Li
Rig1
© ©
A
MOD
COMP
ADJ
POTENTIOMETER
RF TRAY COVER
TRANS!
One)
Fo
FREQ. ADJ.
R358
MSFI020
021894JNM
Figure 4-15
1-F
AGC
Threshold Control
good
reference
waveform to use to tune and
verify
proper modulation
compensation operation.
The modulation compensation adjustment (R358) is
located on the
Uniboard,
and
is accessed from the top of the
RF
Tray
cover.
1.
Set the
Acc Dis/Reset switch
to
Acc Dis.
2.
Using
the
Select/Set switch,
set the
station
to the
tuning
channel.
3.
Key
the station
by
setting
the
LOC PTT
MUXbus bit
(A1/D1).
4.
Monitor the transmitter waveform. The waveform should consist of
a 10
Hz
square
wave, as
shown in Figure
4-17.
5.
Examine
the
waveform for straight
long transitions, however,
a
slight
slant
is acceptable.
If
adjustment is required continue
with
step
6,
otherwise, proceed
to step
8.
6.
Adjust
R358 for
the best
10
Hz
square
wave.
R358 is part of the
Uniboard and is
accessed through the
RF
Tray
cover, as
shown in Figure
4-15.
7.
Dekey
the station
by clearing
the
LOC PTT
MUXxbus
bit
(A1/D1).
8.
Set the
Acc Dis/Xmit switch
to the center
(normal) position.
68P81092E04
3/19/94
eo)