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Page Title:
REPAIR OF CONCEALED SHORT CIRCUITS IN PRINTED WIRING ASSEMBLIES. |
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11-5820-919-40-1
REPAIR OF CONCEALED SHORT CIR-
NOTE
CUITS IN PRINTED WIRING ASSEMBLIES.
Concealed short circuits in printed
If there is an eyelet or
wiring assemblies may be repaired by
plated-through hole not being
performing the following steps.
used for a component termina-
tion, it may be used as a
jumper wire termination.
NOTE
If the end of any one of the
Jumper wires shall be installed
5.
on the rear side of the assem-
jumper wires is to be attached to an
bly whenever possible, but if
etched conductor, plate the stripped end
necessary, jumper wires may be
of the wire on the conductor in a direc-
installed on the component side
tion parallel to the etched conductor
provided they do not cross over
and solder in place.
Then solder the
the top of a component.
ends of the other jumper wires in place.
NOTE
Encapsulate each of the jumper
6.
wires as described in steps 7 thru 10.
The repair of concealed short
circuits involves three steps:
WARNING
(1) isolation of the shorted
area, (2) cutting the conduc-
tors at each side of the short,
Use Freon with good ventila-
and (3) restoring the continu-
tion. Avoid prolonged or
ity by the installation of
repeated breathing of vapor.
jumper wires.
Avoid contact with skin and
eyes. Do not take internally.
Technical personnel familiar with
1.
Clean the areas to be encapsulated
the function of the circuit must deter-
7.
mine the area of the short circuit, the
using Freon TMC solvent.
Be sure that
conductors to be cut, and the jumper
all traces of rosin flux are removed.
wires to be installed.
WARNING
Cut and remove a bit of circuitry
2.
1/8 inch long in each shorted conductor
on each side of the short.
Adhesives are irritating to the
skin and eyes upon contact, and
Form 26-gage insulated copper
may emit harmful vapor.
Use
3.
jumper wires between the designated
only with adequate ventilation.
Avoid all skin and eye contact.
points on each side of the short circuit
area.
Use protective clothing such as
rubber gloves, apron and eye
Wash off immedi-
protection.
4.
Strip the ends of each jumper wire
ately any accidentally contami-
a distance of 1/4 to 5/16 inch.
nated skin areas.
Hand washing
facilities and eye washing
CAUTION
fountain should be provided.
Do not take internally.
The areas to be soldered must
be heated until the solder
flows. Overheating can damage
Use any one of the Narmco Epoxy
8.
the board or nearby components.
Adhesive Kits No. 3135 listed in
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