732A
behind
the
RESET
hole.
The IN
CAL
indicator
should
illuminate.
35.
Calibration
is complete. Record
ail
test
results.
Disconnect all
test
equipment. Cover
the
output
adjustment
access holes and
the
RESET
hole
with
tamper-proof
calibration seals.
4-41. SERVICE/REPAIR
PROCEDURES
4-42.
Introduction
4-43. The Battery Charger Adjustment procedure
is
the
only field
service procedure
for
the
732A.
There
is
no field
serviceable
circuitry
within the
oven/ reference
supply
assembly. All adjustments within the oven must be made
at the
Factory or at a Fluke Technical
Service
Center.
The
following
paragraphs
describe
the Battery
Charger
adjustments
for the 732A.
4-44.
Battery Charger Adjustment
Procedure
CAUTION
This
procedure
wlH cause loss of
standardization.
Calibration
must
be
performed
before reuse
of the Instrument
4-45.
Refer to Figure
4-8.
Perform
this
procedure
to
calibrate
the
battery
charger after repair of the battery
charger
circuit. The
equipment required
is
listed
in
table
4-1.
1 .
Remove ac
power from the instrument.
2. Set the
BATTERY
OPR
switch to OFF.
3.
Remove the top
cover from
the instrument.
4.
Remove
the
AC Module from the instrument.
5.
Locate
test
points TPl, TP2,
and
TPS
on the
A3,
Pre-Regulator
PCB
Assembly(part
of the
AC
Module).
Locate trimpots R20
and
RIO
and jumper
wire
Wl, also on
the AC
Module.
6.
Connect
a 50
kO
rheostat
between TPl and
TP2.
Adjust
the Rheostat
for maximum
resistance.
7.
Connect
Multimeter A
between TPS and TPl.
TPS is
positive
with
respect to
TPL
8.
Reinstall
the
AC
Module
in the instrument.
9.
Apply ac
power to the
UUT
using the
Variac.
Adjust the
Variac for
the line
voltage
indicated on
the rear of
the
instrument.
10.
Adjust
R20
for
a
33.0V
dc
reading
on
Multimeter
A.
1 i.
Turn the ac
power
off by reducing the
Variac
to zero
volts
or
by
unplugging
the
UUT.
12.
Remove
jumper
W!
on A2.
13.
Restore ac power.
14.
Connect
Multimeter
A
between TP2
and
TPl.
TP2
is
positive with respect to TPl.
15.
Set the
BATTERY OPR switch
to
ON.
16.
Set RIO fully
clockwise
(CW).
Multimeter
A
should
read
approximately
45
to
50V
dc.
17.
While
observing Multimeter
A,
adjust the
rheostat toward
minimum
resistance. At
approximately 26V
dc,
the
BTRY CHG
indicator
and CR27
(CR27 is
the voltage
reference
for
the
constant
current
source
in
the battery
charger
circuit,
located
on A2) should
come on. The ac line
current should jump to approximately
1
10 mA at
H5Vac
(55
mA at
220V
ac).
18.
Adjust the
Rheostat
for a Multimeter A
reading of 32V dc,
19. Turn RIO
counter-clockwise
(ccw)
until
the
BTRY CHG
indicator
and
CR27 go out. Note that
the ac line current has dropped.
20.
Adjust the
Rheostat toward minimum
resistance,
while
observing
the BTRY
CHG
indicator. When the BTRY CHG
indicator
lights,
CR27
lights,
and
the
ac
line
current increases
suddenly. Multimeter A should read
between
24.5
and
26.5V dc.
2 1 . Adjust the Rheostat until the
BTRY
CHG
and
CR27
indicators
turn
off. Multimeter A
should
indicate a dc
voltage
greater than
+3
IV.
22.
Disconnect
ail test
equipment
and the
rheostat.
23.
Remove
the
AC
Module from the 732A.
24. Reinstall
jumper
W1
.
25.
Reinstall the
AC Module.
26.
Battery
Charger adjustment is now complete.
Perform
the Calibration adjustment procedure
described
earlier
in
this section,
4-46.
TROUBLESHOOTING
4-47. Introduction
4-48. The
information
in
this
section
describes
troubleshooting
procedures
for the 732A. The section is
divided
into two
parts: External Symptom
Troubleshooting
and
Internal
Voltage
Measurements.
4-14
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