~
To
prevent getting moisture inside the instrument
during external
cleaning,
use
only enough liquid to
dampen
the
cloth
or
applicator.
CLEANING. Loose dust
on
the outside of the
instrument can
be
removed with a soft cloth or small soft-
bristle brush.
The
brush
is
particularly useful for dislodging
dirt
on
and
around the controls
and
connectors. Dirt that
remains can
be
removed with a soft cloth dampened
in
a
mild
detergent- and-water solution.
Do
not use abrasive
cleaners.
Two plastic light filters, one blue
and
one clear, are pro-
vided
with the oscilloscope. Clean the light filters
and
the
CRT face with a soft lint-free cloth dampened with either
isopropyl alcohol or a
mild
detergent-and-water solution.
Maintenance-2445A/2455A
Service
Interior
To gain access to internal portions of the instrument for
inspection
and
cleaning, refer
to
the "Removal
and
Replacement Instructions"
in
the ·corrective Maintenance·
part of this section.
INSPECTION. Inspect the internal portions of the
instrument for damage and wear, using Table
6-3
as
a
guide. Deficiencies found should
be
repaired immediately.
The corrective procedure for most visible defects is
obvious; however, particular care must
be
taken if heat-
damaged components are found. Overheating usually
indicates other trouble
in
the instrument, therefore it
is
important that the cause
of
overheating
be
corrected to
prevent recurrence of the damage.
If
any
electrical component is replaced, conduct a
Per-
formance Check for the affected circuit
and
for other
closely related circuits (see Section
4).
If repair
or
replace-
ment work is done
on
any of the power supplies, conduct
a complete Performance Check and,
if so indicated,
an
instrument readjustment (see Sections 4
and
5).
Table 6-3
Internal Inspection Check List
Item
Inspect For Repair Action
Circuit Boards Loose, broken, or corroded solder
Clean solder corrosion with an eraser
and
flush with
connections. Burned circuit boards. isopropyl alcohol. Resolder defective connections.
Burned, broken,
or
cracked circuit- Determine cause of burned items
and
repair. Repair
run
plating.
defective circuit runs.
Resistors
Burned, cracked, broken, blistered. Replace defective resistors. Check tor cause
of
burned
component
and
repair
as
necessary.
Solder Connections
Cold solder or rosen joints.
Resolder joint
and
clean
with isopropyl alcohol.
Capacitors Damaged or leaking cases. Replace defective capacitors. Clean solder connections
and
Corroded solder
on
leads or flush with isopropyl alcohol.
terminals.
Semiconductors
Loosely inserted
in
sockets. Firmly seat loose semiconductors. Remove devices having
Distorted pins. distorted pins. Carefully straighten pins
(as
required to fit
the socket), using long-nose pliers, and reinsert firmly.
Ensure that straightening action does not crack pins,
causing them to break off.
Wiring
and
Cables Loose plugs or connectors. Burned, Firmly seat connectors. Repair or replace defective wires or
broken,
or
frayed wiring.
cables.
Chassis Dents, deformations,
and
damaged Straighten, repair, or replace defective hardware.
hardware.
6-3
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