Tektronix 422, Instruction Manual

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Maintenance—Type 422 AC-DC
provides dust protection fo r the fro n t panel and the CRT
face. The fro n t cover should be installed for storage or
transportation.
CAUTION
Avoid the use of chemical cleaning agents which
might damage the plastics used in this instrument.
Avoid chemicals which contain benzene, toluene,
xylene, acetone or similar solvents.
Exterior. Loose dust accumlated on the outside o f the
Type 422 can be removed with a soft cloth or small paint
brush. The paint brush is particularly useful fo r dislodging
d irt on and around the front-panel controls. D irt which
remains can be removed with a soft cloth dampened in a
mild detergent and water solution. Abrasive cleaners should
not be used.
CRT. Clean the plastic light filte r, faceplate protector
and the CRT face w ith a soft, lint-free cloth dampened with
denatured alcohol. The CRT mesh filte r can be cleaned in
the following manner:
1. Hold the filte r in a vertical position and brush lightly
with a soft No. 7 watercolor brush to remove light coatings
of dust or lint.
2. Greasy residues or dried-on d irt can be removed with
a solution of warm water and a neutral pH liquid detergent.
Use the brush to lightly scrub the filter.
3. Rinse the filte r thoroughly in clean water and allow
to air dry.
4. If any lin t or d irt remains, use clean low-pressure air
to remove. Do not use tweezers or other hard cleaning tools
on the filte r, as the special finish may be damaged.
5. When not in use, store the mesh filte r in a lint-free,
dust-proof container such as a plastic bag.
Interior. Dust in the interior of the instrument should
be removed occasionally due to its electrical conductivity
under high-humidity conditions. The best way to clean the
interior is to blow o ff the accumulated dust with dry, low-
pressure air. Remove any d irt which remains w ith a soft
paint brush or a cloth dampened with a mild detergent and
water solution. A cotton-tipped applicator is useful fo r
cleaning in narrow spaces or fo r cleaning ceramic terminal
strips and circuit boards.
The high-voltage circuits, particularly parts located in
the high-voltage compartment and the area surrounding the
post-deflection anode connector, should receive special
attention. Excessive d irt in these areas may cause high-
voltage arcing and result in improper instrument operation.
WARNING
The battery pack is capable of delivering a very large
current if accidentally short circuited. Be careful to
prevent shorting the battery terminals or associated
wires with tools metal work bench etc. A severe
burn can be obtained if a ring, watch band, etc.
comes in contact with the battery terminals.
Battery-Pack Cleaning. When the battery pack is over­
charged or when discharged to the point o f polarity rever­
sal, gas is formed w ithin the nickel-cadmium cell. The
nickel-cadmium cells used in the battery pack incorporate a
vent so this internal pressure does not damage the battery.
However, as the internal pressure is relieved, a small amount
of the electrolyte may be expelled with the gas. Although
the cells w ill not be damaged unless this happens repeat­
edly, this loss of electrolyte may result in shorter overall
battery life. The battery
box should be inspected occasion­
ally for any electrolyte residue on the battery pack or in
the battery compartment. Any residue which is found
should be cleaned away w ith a 2% solution of boric acid in
water. A 2% solution of boric acid can be obtained by
dissolving 1 % teaspoons o f boric acid powder in one cup of
water. A fter the residue has been cleaned from the battery
pack and the battery compartment, dry the wetted area
thoroughly with a soft cloth.
Lubrication
The reliability of potentiometers, rotary switches and
other moving parts can be maintained if they ary kept
properly lubricated. Use a cleaning-type lubricant (e.g.,
Tektronix Part No. 006-0218-00) on switch contacts.
Lubricate switch detents w ith a heavier grease (e.g.,
Tektronix Part No. 006-0219-00). Potentiometers which
are not permanently sealed should be lubricated with a
lubricant which does not affect electrical characteristics
(e.g., Tektronix Part No. 006-0220-00). The pot lubricant
can also be used on shaft bushings. Do not over lubricate. A
lubrication kit containing the necessary lubricants and
instructions is available from Tektronix, Inc. Order
Tektronix Part No. 003-0342-00.
Visual Inspection
The Type 422 should be inspected occasionally fo r such
defects as broken connections, broken or damaged ceramic
strips, improperly seated transistors, damaged circuit boards
and heat-damaged parts.
The corrective procedure fo r 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 over-heating be corrected to
prevent recurrence of the damage.
Transistor Checks
Periodic checks of the transistors in the Type 422 are
not recommended. The best check of transistor perform­
ance is actual operation in the instrument. More details on
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