Tektronix 2440, Руководство пользователя

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Maintenance— 2440 Service
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; it is important, therefore,
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, verify
that the affected power supply meets the voltage and rip­
ple tolerance requirements under Specification in Section 1
of this manual.
To p re v e n t d a m a g e fro m e le c tric a l a rc in g , e n s u re
th a t c irc u it b o a rd s a n d c o m p o n e n ts a re d ry b e fo re
a p p ly in g p o w e r to th e in s tru m e n t.
CLEANING. To clean the interior, blow off dust with
dry, low-pressure air (approximately 9 psi). Remove any
remaining dust with a soft brush or a cloth dampened with
a solution of mild detergent and water. A cotton-tipped
applicator is useful for cleaning in narrow spaces and on
circuit boards. If these methods do not remove all the dust
or dirt, the instrument may be spray washed using a solu­
tion of 5% mild detergent and 95% water as follows:
E x c e p tio n s to th e fo llo w in g c le a n in g p ro c e d u re a re
th e C H 1 a n d C H 2 A tte n u a to r a s s e m b lie s . C le a n
th e s e a s s e m b lie s o n ly w ith is o p ro p y l a lc o h o l a s
d e s c rib e d in S te p 4 o f th e c le a n in g p ro c e d u re . In
a d d itio n , a ll o th e r F ro n t P a n e l c o n tro ls a re s e a le d
a n d re q u ire n o m a in te n a n c e .
1. Gain access to the parts to be cleaned by removing
easily accessible shields and panels (see "Removal and
Replacement Procedure").
2. Spray wash dirty parts with the detergent-and-water
solution; then use clean water to thoroughly rinse them.
3. Dry all parts with low-pressure air.
4. Clean switches with isopropyl alcohol and wait 60
seconds for the majority of the alcohol to evaporate. Then
complete drying with low-pressure air.
5. Dry all components and assemblies in an oven or
drying compartment using low-temperature (125°F to
150°F) circulating air.
Table 6-2
External Inspection C heck List
Item Inspect For Repair Action
Cabinet, Front Panel,
and Cover
Cracks, scratches, deformations, damaged
hardware or gaskets.
Touch up paint scratches and replace
defective components.
Front-panel Controls Missing, damaged, or loose knobs, buttons,
and controls.
Repair or replace missing or defective
items.
Connectors
Broken shells, cracked insulation, and
deformed contacts. Dirt in connectors.
Replace defective parts. Clear or wash out
dirt.
Carrying Handle Correct operation. Replace defective parts.
Accessories Missing items or parts of items, bent pins,
broken or frayed cables, and damaged con­
nectors.
Replace damaged or missing items, frayed
cables, and defective parts.
6-5