Mains Input Resistance Readings - Racal Instruments 9081 Maintenance Manual

TABLE
6
Mains Input Resistance Readings
Left
Hand
Switch* Right
Hand
Switch*
Mains
Plug Resistance
Readings
Down Up
11.5
-
15.
5Q
Up
Up
14.5 -
19.
5Q
Down
Down
45
-
61
Q
Up
Down
57
-
77Q
*Left
hand and
right
hand areas
seen
when
looking at
the rear
panel
.
(7)
Refer to Fig. 5.1,
and with the multimeter
set to
measure ohms,
measure the resistance
between
the
tags
A,
B
and
C
on
the
rear
panel
tag
strip
and
chassis.
Note
the correct
connection
of the
ohmeter
leads as
shown
in
Fig. 5.1
.
(8)
Set the
POWER
switch
to
OFF
and
the
rear
panel
STANDARD
switch
to
INTERNAL.
(9)
Finally,
connect the a.c. mains supply lead
to
the
rear
panel plug.
(10)
Plug
in
the a.c.
mains
supply.
(11)
Switch
POWER
to
ON.
Check
that
the
Power
indicator illuminates
and
the
digital
display
comes on.
(12)
Refer
to Fig.
5.1 and, with a multimeter,
measure the d.c. voltages
relative
to chassis,
on
the
rear
panel tag
strip,
at points
A,
B
and
C
as
follows:-
Tag
A
+24V ± IV
Tag
B
+12V±0.5V
Tag
C
-6V
±0.25
9081
&
9082 Vol
.
2
5-4