Troubleshooting Tips; Power Supply - HP 182C Operating And Service Manual

Model 182C
Table 8-3.
Low
Voltage
Power
Supply
Troubleshooting Tips
Symptom
Suggested
Checks
'Most
common
fault.
All supplies
low or
high
and
unregulated.
Check
ac input
line
voltage and
position
of
rear-panel
SELECTOR
switch (115 or
230V)
'Check
+ 100V
supply and
A1A2VR2.
(-tlOOV supply
is
used
as reference for
—100V,
-•-15V,
—12.6V
supplies
and
A1A2VR2
provides
reference voltage for -t-IOOV supply).
One
supply
high
and
unregulated with
high
ripple.
Check comparator and
series regulator.
One
supply low.
Check
for
excessive current
drain.
'Check comparator.
No
output
from one
supply.
Check
fuse.
Check
regulator.
(Supplies are current
limited.
Fuse
will
not
open due
to shorted
load.)
Open
line fuse.
Check ac
line
voltage
ar>d
position of
rear-panel
SELECTOR
switch.
'Check
rectifier diodes.
Check
filter
capacitors.
Check power
transformer.
Table 8-4.
Low
Voltage Power
Supply Measurement
Conditions
1.
Setcontroisasfoiiows:
LiNE
power
ON.
Plug-ins
not
installed.
Line voltage
1 1
5 Vac.
2.
All
dc
voltages are referenced to ground.
3. All dc voltages
measured with
HP
Model 1414
A
Auto
Voltmeter.
(100
MH
input
impedance).
4.
Voltages indicated
on
schematic remain approximately
as
indicated
when power
supply
is
operated with
HP
Model
101
33A
Service Extender.