TM11-6125-256-34
(1) Using a 23- to 37 5-watt pencil-type soldering
b Repeat the procedures of paragraph 4-1 If the
iron, heat and peel off the polyurethane coating from the
measurements of paragraph 4-7, steps d(1) through d(3),
component to be replaced
are satisfactorily made, the assembly has been repaired
satisfactorily
(2) Using the soldering iron and a vacuum solder
c Turn off dc input power
removing tool remove solder from the component leads
and remove the component leads Where necessary use
an appropriate heat sink to prevent damage to adjacent
assembly from the motor-generator as described in
components
paragraph 3-11a
CAUTION
e Remove self-locking nuts (21, fig 4-5) screws (19
25 and 26), lock washers (22), washers (23), loop clamp
Do not clean printed circuit board assembly
(28) electrical lead (27) and sleeve spacers (24)
(29) unless absolutely necessary as cleaning
solvents may damage coating
f With the exception of the two 1/2-inch diameter
mounting holes at the center of the board the adjustment
(3) Using the old component as a guide form and cut
shafts and bushings for resistors R14 and R15 and the
the replacement component leads as required After
bottom of the post and bracket assembly spray the
positioning the component or leads in place solder
voltage and frequency regulator assembly with Hysol PC
securely as follows
28 STD urethane coating (Hysol Division of the Dexter
Corporation Olean NY) as follows
NOTE
WARNING
Equivalent soldering materials may be used
Contents of spray can are under pressure and
flammable Do not spray near fire, flame or
heated surfaces Do not store can at a
(a) Use the 23- to 37 5-watt soldering iron Be sure
temperature above 120F (48 8C) Avoid
breathing of vapors prolonged contact with
the tip is clean, free from oxides and coated with a film of
the skin contact with open breaks in the skin
solder
and ingestion Wash hands thoroughly after
handling and before eating and smoking
(b) Use Kester solder 66-37 (3/64-inch diameter
core) and Kester No 1544 liquid flux (Kester Solder
(1) Shake spray can a few times to completely mix
Company, Newark New Jersey) The solder consists of
material in spray can
63 percent tin and 37 percent lead and has a melting
temperature of 357F (181C)
(2) While spraying, hold spray can approximately 6
inches from area to be srayed
(c) Clean the joints with Lonco flux remover
(3) Allow coating to cure for a minimum of 4 hours
(London Chemical Co, Melrose Park Illinois)
at room temperature before handling sprayed surfaces
Allow 24 hours at room temperature for complete curing
4-10. Replacement of Regulator Board
g Assemble printed circuit board subassembly to
a Secure printed circuit board assembly (29, fig 4-5)
bracket and post assembly (84 fig 4-5) with self-locking
to bracket and post assembly (84) with self-locking nuts
nuts (21) screws (19 25 and 26) lock washers (22)
(21), screws (19, 25, and 26), lock washers (22) washers
washers (23) and sleeve spacers (24) Be sure that
(23), and sleeve spacers (24) Be sure that electrical lead
electrical lead (27) is placed onto center screw (26) before
(27) is placed onto center screw (26) before installing loop
installing loop clamp (28)
clamp (28)