Maintenance
6-6
CSA7404B, TDS7704B, TDS7404B, TDS7254B & TDS7154B Service Manual
Table 6- 2: Internal inspection check list (Cont.)
Item Repair actionInspect for
Capacitors Damaged or leaking cases.
Corroded solder on leads or
terminals.
Remove and replace damaged
circuit board.
Semiconductors Loosely inserted in sockets.
Distorted pins.
Firmly seat loose semic onduc-
tors. Remove devices that have
distorted pins. Carefully straight-
en pins (as required to fit the
socket), using long-nose pliers,
and reinsert firm ly. Ensure that
straight ening action does not
crack pi ns, causing them to
break off.
Wiring and cables Loose plugs or connectors.
Burned, broken, or f rayed wiring.
Firmly seat connectors. Repair or
replace modules with defective
wires or cabl es.
Chassis Dents, deformations, and
damaged hardware.
Straight en, repair, or replace
defective hardware.
Cleaning Procedure — Interior. To clean the instrument interior, do the following
steps:
1. Blow off dust with dry, low-pressure, deionized air (approximately 9 psi).
2. Remove any remaining dust with a lint-free cloth dampened in isopropyl
alcohol (75% solution) and rinse with warm deionized water. (A cotton-
tipped applicator is useful for cleaning in narrow spaces and on circuit
boards.)
STOP. If, after doing steps 1 and 2, a module is clean upon inspection, skip the
remaining steps.
3. If steps 1 and 2 do not remove all the dust or dirt, the instrument may be
spray washed using a solution of 75% isopropyl alcohol by doing steps 4
through 8.
4. Gain access to the parts to be cleaned by removing easily accessible shields
and panels (see Removal and Installation Procedures).
5. Spray wash dirty parts with the isopropyl alcohol and wait 60 seconds for the
majority of the alcohol to evaporate.
6. Use hot (120 _F to 140 _F) deionized water to thoroughly rinse them.
7. Dry all parts with low-pressure, deionized air.
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