Tektronix PSC1125, Instruction Manual

Page: 58 / 92

Maintenance
7-6
PSC 1125 Digital Television Parallel-to-Serial Converter Instruction Manual
Table 7-3: Internal inspection check list (Cont.)
Item Repair action Inspectfor
Solderconnections Cold solderorrosin joints Resolderjoint and clean with
isopropyl alcohol.
Capacitors Damaged orleaking cases;
corroded solder on leads or
terminals
Remove damaged module and
replace with a new module from
the factory.
Semiconductors Loosely inserted in sockets;
distorted pins.
Firmly seat loose semiconducĆ
tors. Remove devices that have
distorted pins. Carefully straightĆ
en pins (as required to fit the
socket), using longĆnose pliers,
and reinsert firmly. Ensure that
straightening action does not
crack pins, causing them to
break off.
Wiring and cables Loose plugs orconnectors;
burned, broken, or frayed wiring.
Firmly seat connectors. Repair or
replace modules with defective
wires or cables.
Chassis Dents, deformations, and damĆ
aged hardware
Straighten, repair, or replace
defective hardware.
Interior Cleaning Procedure.
If, after doing steps 1 and 2 below, a module is clean
upon inspection, skip the remaining 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.)
3. If steps 1 and 2 do not remove all the dust or dirt, spray wash the converter
using a solution of 75% isopropyl alcohol and preform 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 on page 7–8).
5. Spray wash dirty parts with the isopropyl alcohol, and wait 60 seconds for
the majority of the alcohol to evaporate.
6. Use hot (48.9
_
C to 60
_
C, 120
_
F to 140
_
F) deionized water to thoroughly
rinse the parts.