Racal Instruments 9901 Maintenance Manual page 58

PERFORMANCE
TESTS
AND
CALIBRATION
NOTE:
If
fhe Racal Synthesized
Signal
Generator
is
used, with
its
frequency standard
synchronised
to that of the
9901
,
a readout accuracy
of ±1 count
will
be
obtained.
Segment, Decimal
Point
and
Self
Check
5.6
(1)
Connect
the a.c. supply and
set
the
POWER
switch
to
ON.
(2)
Set the
CHECK/OPERATE
switch
to
CHECK.
(3)
Depress the
FREQ.
'A'
MAN
button
and
verify that the
GATE
indicator
illuminates.
(4)
The
instrument should
now
read 1000 kHz.
Refer to Table
7 and check
the
display
and decimal
points (Freq.
column)
for
each
'n'
range
button.
(5)
Depress the
PERIOD
'A'
button
and
verify the readout and decimal
points
according
to
the Period column
of
Table
7.
(6)
Briefly
hold
in
the RESET
button
and check
that the display reads
'all
eights'
(segment check).
TABLE 7
SELF
CHECK READOUT
Range
'n'
Selected
Gate
Time
Display
(±
1
count)
Frequency
Period
1 1
ms
001000. 000001
.
10
10
ms 01000.0
00001.0
10^
TOO ms
1000.00
0001
.00
10^
1
sec
*
000.000
001 .000
lo"^
10 sec
*00.0000
01.0000
10^
100 sec
*0.00000
1
.00000
NOTE:
With
readouts
marked
(*)
the
most
significant digit will
overspill
and
the
OVERFLOW
lamp
will illuminate after
the appropriate gate time.
5-5
9901 Vol. 2