TM 11-5820-922-40-1
SECTION I
CIRCUIT CARD ASSEMBLY REPAIR PROCEDURES
GENERAL.
flows beyond the bend radius of a com-
3-4. This section contains description
ponent lead is not acceptable, except
and definitions of standards to be
for small diameter components (for
observed followed by procedures to be
example, glass diodes). The maximum
performed for repair of circuit cards
solder height, including component lead,
and replacement of components. Read the
on the bottom of the board is 0.062 inch
procedures in this section before
attempting card repair.
exceed 0.062 inch.
STANDARDS.
permisssible voids and pinholes, the
solder must fill the hole to the point
CARDS. The following paragraphs contain
where the solder covers the entire inner
standards to be observed when soldering
surface of the hole. For eyelet holes
circuit cards.
or standoff terminals with circuit con-
nections, the solder should flow between
the eyelet and the pad for at least four-
ifths of the circumference.
is an area which is not filled with
solder, the extent of which is com-
pletely visible. For cards with eyelets
or plated-through holes, voids in the
joints (fig 3-4) where the solder balls
circuit side of a solder joint are per-
at the point of contact with a pad or
lead are not acceptable.
missible, provided that they are not
deeper than half of the hole depth and
do not extend over more than a quarter
of the hole area. If no circuit is con-
All components may be soldered by either
flow soldering or by hand soldering.
nected to the pad on the side of the
void, the void may extend over the
The completed joint must have a clear,
smooth appearance which indicates proper
entire hole area if the outline of the
soldering. Examples of preferred solder
lead is visible. Voids in unsupported
holes may extend through the hole but
connections are shown in figure 3-5.
should not extend over more than a fifth
of the hole area.
STANDARDS. Cracks, chips, or gouges in
the base material should not exceed the
following:
a hole in the surface of the solder
which indicates the absence of solder
beneath the surface, the extent of which
1. Cracks or chips should not exceed
back from the edge of the hole more than
is not visible. Pinholes (fig 3-2)
should not be permitted adjacent to the
0.040 inch.
component lead or wire.
2. Cracks, chips, and gouges at the
edge of the board should not exceed 1/3
to cover the entire pad area. Voids and
of the board thickness or extend back
pinholes in these areas are acceptable.
more than 0.12 inch from the edge.
