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Section V
Paragraphs 5-18 to 5-22
b. If the meter tracking error is greater than 0.02
db, adjust A3R57 (See Figure 5-10) and repeat meas-
urement
until
meter
tracking
error
is
less
than
20.02 db.
5-18.
REPAIR
AND
REPLACEMENT.
5-19.
Certain
procedures
and
precautions
must
be
followed when repairing or replacing any component of
the
Model
415Е.
Most of the amplifier
and power
Supply
circuit
components
are
located on the etched
circuit board.
Instructions for working on the etched
circuit
board
are
summarized
in Paragraph
5-20.
Always disconnect the АС or battery power before re-
placing or soldering any parts. Instruction for removal
and
replacement of switches is detailed in Paragraph
5-27.
5-20.
ETCHED
CIRCUITS.
5-21. The etched circuit board in the SWR Meter is of
the
plated-through
type consisting
of metallic
сопе
ductors bonded to both sides of insulating material.
Soldering can be done from either side ofthe board with
equally good results. Table 5-3.lists requiredtools and
materials.
Following are recommendations and pre-
cautions
pertinent
to etched
circuit
repair
work.
а. Avoid unnecessary component substitution: it can
result
in damage to the circuit board and/or adjacent
components.
b. Do not use а high-power soldering ігоп оп etched
Circuit boards.
Excessive
heat may lift a conductor
or damage the board.
Model 415Е
с. Use a suction device (Table 5-3) or wooden tooth-
pick to remove
solder from component mounting holes.
DO NOT USE A SHARP METAL OBJECT SUCH AS AN
AWL OR TWIST DRILL FOR THIS PURPOSE, SHARP
OBJECTS
MAY
DAMAGE
THE
PLATED-THROUGH
CONDUCTOR,
d. After
soldering,
remove
excess
flux from
the
Soldered
area
and apply a protective coating to pre-
vent contamination
and corrosion.
See Table 5-3 for
recommendations.
5-22. COMPONENT
REPLACEMENT,
a. Remove defective component from circuit board.
b. Remove solder from mounting holes usingasuc-
tion desoldering
aid (Table 5-3) or wooden toothpick.
c. Shape
leads of replacement component to match
mounting hole spacing.
d.
Insert component leads into mounting holes and
position component
as original
was positioned.
DO
NOT
FORCE
LEADS
OF
REPLACEMENT
COMPO-
NENT
INTO
MOUNTING
HOLES.
Sharp lead ends
may damage plated-through conductor.
Note:
Axial lead components, suchas resist-
ors
and tubular
capacitors, can be replaced
without unsoldering.
Clip leads near body of
defective component, remove component and
Straighten leads left in board.
Wrap leadsof
replacement component one turn around orig-
inal leads.
Solder wrapped connection, and
clip off excess lead.
Table 5-3.
Etched Circuit Soldering Equipment
Item
Use
Specification
Wattage rating:
37.5
Tip Temp:
750 - 800°F
Tip Size:
1/8" OD
Item Recommended
Ungar #776 Handle with
Ungar #1237 Heating Unit
Soldering Tool
Soldering
Unsoldering
|==
===
===
Soldering Tip,
Soldering
general purpose | Unsoldering
Shape:
chisel
Size:
1/8"
Ungar #PL113
Unsoldering multi-
connection components
De-soldering aid
Suction device to remove
molten solder from
Soldapullt by the Edsyn
Company,
Arleta,
(e.g., tube sockets
connection
California
Resin (flux)
Remove
excess flux
Must not dissolve etched
Freon
Solvent
from soldered area
circuit base board ma-
Acetone
before application of
terial or conductor
Lacquer Thinner
protective coating
bonding agent
Isopropyl Alcohol (100% dry)
Solder
Component replacement
Resin (flux) core, high
Circuit board repair
tin content (60/40 tin/
Wiring
lead), 18 gauge (SWG)
preferred
Protective
Contamination,
corrosion
Good electrical insula-
Krylon* 11302
Coating
protection after soldering
tion, corrosion-
prevention properties
Humiseal Protective Coating,
Type 1B12 by Columbia
Technical Corp. Woodside
77, New York
*Krylon Inc., Norristown,
Pennsylvania
5-8
02152-3
алые
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