After Service Safety Checks; After Service Safety Checks; Visual Inspection; Check Line Cord Ground - HP 8340B Manual

HP 8340B/41B Assembly-Level Service
After Service Safety Checks
VISUAL INSPECTION
Visually Inspect the interior of the instrument for any signs of abnormal internally
generated heat,
such
as discolored printed circuit boards or components,
damaged insulation, or evidence
of
arcing.
If
you
find any signs of abnormal heat, determine
and
remedy the cause.
CHECK LINE CORD GROUND
Using
a
suitable ohmmeter, check the resistance from the instrument enclosure to the ground
pin on
the power cord plug. The reading must be less than
1t2.
Flex the
power
cord while making this
measurement to determine whether intermittent discontinuities exist.
If
the resistance
is
greater
than 1A, replace the
faulty line cord.
CHECK THE LINE/NEUTRAL
With the instrument disconnected from
line power, and the line switch on, check the resistance
from
the instrument enclosure to the line
and neutral (tied together). The resistance must be at least
2
Ma.
If
the resistance is less than
2
Mf2, DO NOT CONNECT THE INSTRUMENT TO
LINE POWER!
Troubleshoot the source of
the
problem.
CHECK THE
LINE FUSE
Verify that
a
correctly rated fuse is installed, and the line module voltage selector cam is
set properly.
HP 8340B/41B
Assembly-Level Service After Service Safety Checks A-51