Lubrication; Semiconductor Checks; Periodic Readjustment - Tektronix 2246 1Y Service Manual

Maintenance—2246 1Y and 2246 Mod A Service
INSPECTION. Inspect the internal portions of the
2246 1Y or 2246 Mod A for damage and wear, using
Table 6-3 as a guide.
mediately. The corrective procedure for most visible
defects is obvious; however, particular care must be
taken if heat-damaged components are found.
Since overheating usually indicates other trouble in
the instrument, it is important that the cause of over­
heating be corrected to prevent further damage.
If any electrical component is replaced, conduct a
Performance Check for the affected circuit and for
other closely related circuits (see Section 4 for the
Performance C heck). If repair or replacement work
is done on any of the power supplies, conduct a
complete Performance Check and, if so indicated,
an instrument readjustment
Adjustment Procedure).
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> CAUTION \
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To prevent damage from electrical arcing, en­
sure that circuit boards and components are
dry before applying power to the instrument.
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
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
solution of 1% mild detergent and 99% water as
follows:
1. Remove covers and shields to reach parts to be
cleaned (see Removal
Instructions).
2. Spray wash dirty parts with the detergent-and-
water solution; then
thoroughly rinse them.
3. Dry all parts with low-pressure air.
4. Dry all components and assemblies in an oven
or drying compartment using low-temperature
(125°F to 150°F) circulating air.
6 -4
Repair deficiencies im­
(see Section 5 for
W V X A O
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applicator is useful for
and Replacement
use clean water
SWITCH CONTACTS. Switch contacts are perma­
nently treated when assembled. Neither cleaning nor
other preventive maintenance is necessary, unless
the switch board is replaced or the switch assembly
has remained disassembled for a long period of
time.
A regular periodic lubrication program for the instru­
ment is not necessary. Most of the potentiometers
used in this instrument are permanently sealed and
generally do not require periodic lubrication. The
backs of the front-panel knob guides have been
lubricated when assembled and will require lubri­
cation again only when the front panel assembly is
replaced. Rotary switches are installed with proper
lubrication when assembled and will require lubri­
cation only when the rotor is replaced.

SEMICONDUCTOR CHECKS

Periodic checks
semiconductors in the oscilloscope are not recom­
mended. The best check of semiconductor per­
formance is actual operation in the instrument.

PERIODIC READJUSTMENT

To ensure accurate measurements, check the per­
formance of this instrument every 2000 hours of
operation, or if used infrequently, once each year. If
you replace any components, it may be necessary
to readjust the affected circuits.
battery used in the 2246 1Y MUST be replaced
annually. Refer to Corrective Maintenance in this
section for more
replacement.
Complete Performance Check instructions are given
to
in Section 4 of this manual; adjustment instructions
are given in Section 5. The Performance Check
Procedure can
troubles in the instrument. In some cases, minor
problems may be revealed or corrected by readjust­
ment. If only a partial adjustment is performed, see
Table 5-1 (the interaction chart) for possible adjust­
ment interaction with other circuits.

LUBRICATION

of the transistors and
The silver-oxide
information on
be helpful in localizing
other
battery
certain