Miscellaneoustroubleshootingtips; High Voltage; Crt Intensity - HP 182C Operating And Service Manual

Model 182C
Table
8-2-
Miscellaneous Troubleshooting Tips
Symptom
Suggested
Checks
Intermittent deflection
Check
for loose
or corroded connections
to
I
CRT
neck
pins.
Check
for
intermittent open
in
deflection
leads.
(Refer to note for additional
tips.)
Intensity variation
causes trace
shift
(either axis).
Check
for
open
deflection
lead
in
axis affected.
If
trouble
is
vertical axis,
check
vertical
plug-
in
connector and mating connector
in
oscilloscope.
No
output from Gate
or
Sweep
output
jacks.
Check
emitter-follower for
output
affected
Check
circuit
interconnections
(cables,
connectors).
Improper
Z-axIs
modulation.
Check normal operation with
plug-ins installed.
If
OK, check connections and check
in-puts.
(Refer to note for additional
tips.)
CRT
trace
develops
distortion
over
long
period.
Instrument
may
have
been
subjected to high
magnetic
field,
magnetizing
CRT
elements.
Possible
CRT
malfunction.
Improper
deflection
If
symptom
is
apparent
in
both
vertical and
horizontal axes,
check High
Voltage.
If
H.V.
is
low,
expanded
display
results.
If
H.V.
is
high,
causes contracted
display.
Vertical axis only: check
vertical plug-in,
deflection leads
and connectors.
Horizontal
axis only:
check with replacement
time base
plug-in.
If
OK. problem
is in
time
base
plug-in.
otherwise check
oscilloscope
horizontal amplifier, deflection leads and
connectors.
NOTE
It
may
be helpful to
isolate
the Gate
amplifier
from
the H.V. supply
to
isolate
the problem. Disconnect the Gate Out
cable
connection from
the
High Voltage supply
and ground
the
High Voltage Gate Coax
connection.
This
will
eliminate the Gate
amplifier
as a
source of H.V. intensity trouble.
In this
mode,
CRT
intensity
will
only be
controlled
by
the
INT LIMIT
adjustment. This potentiometer
is
located
on
the H.V. Osc
&
Rectifier
Assembly, A6.