Preliminary System Checks; Output System - Racal Instruments 9081 Maintenance Manual

(14)
With
HOLD
still
selected,
turn
the spin
wheel and check
that the
frequency does not
change.
NOTE:
If
the
channel spacing
is
changed
from
20kHz
to
6.25kHz,
or
from
50
to
15kHz,
the carrier frequency
will
change.
(15)
Set:-
Carrier
frequency
to
390MHz.
FINE
TUNE
switch
to
1NT.
TUNE
switch
to
SLOW.
(16)
Rotate the
FINE
TUNE
coarse (outer) control
and
verify that
frequencies of
389 .9MHz
and
390.lMHz
can be obtained.
Check
that the fine tune
ON
indicator
lights.
(17)
Centralize the
FINE
TUNE
outer control
and
then
rotate
the fine
(inner)
control
.
Verify that the
frequency display
changes by
at
least
10kHz.
(18)
Set the
FINE
TUNE
switch
to
EXT
.
(19)
Connect
the internal
+I2V
rail
(tag
12
on wafer
I
rear of either the
TUNE
or
FINE
TUNE
switches)
to
a
flying
lead.
Alternately
apply and remove
this
voltage
at the pin of
the front
panel
SLOW
SWEEP
socket.
At
a carrier
frequency of
approximately
390
MHz
verify that the
frequency changes by a
least
300kHz.
(20)
Set the
FINE
TUNE
switch
to
OFF.
(21)
Select
Range 5 and
tune
to
540MHz.
Note
the
displayed frequency.
(22)
Operate
the
OUTPUT
switch several times rapidly
through
its
NORMAL/OFF/X2
positions
and check
that the
frequency display
returns
to
its
original
value. Repeat
this
operation, pausing
each
time in
the
OFF
position.
(23)
Set the
OUTPUT
switch
to
NORMAL.
PRELIMINARY SYSTEM CHECKS
Output
System
5. 7
Test
Equipment
Required
Page 5-2
Table 5
Millivol tmeter (True RMS)
Item
2
5.8
Procedure
(I)
Connect
the
unit
under
test
(UUT)
50Q
output socket
to
the
9301
50Q
input socket.
9081
&
9082
Vol. 2.
5-8