TM 11-6125-240-34
Lead dimensions (B, fig. 4-13)
Dimension A
Reference designation
Dimension B
R6
0.6
0.250
R7
0.9
0.296
R8 thru R22
0.6
0.250
R24
0.6
0.250
R25
0.9
0.296
R26
0.8
0.265
R27
0.8
0.265
CAUTION
(clear), London Chemical Co., Melrose Park, Ill., or
Place soldering iron in contact with lead wire
equivalent.
or circuit board track. Solder must be melted
CAUTION
by heat received from lead wire or circuit
Restrict application of the flux remover only
board track, not by direct contact with solder-
to areas necessary to remove flux, because
ing iron. Do not overheat printed circuit
t h i s cleaning agent deteriorates the
board.
polyurethane coating.
(5) Cut rigid vertical leads of parts, if necessary,
(3) Thoroughly mix polyurethane EN-4 Part A
under circuit board to 1/16 1/32 inch, as shown in C,
(straw) and Part B (amber) with a metal mixing paddle
(100 parts A-17.5 parts B by weight). Dilute with a
CAUTION
50/50 blend of methyl ketone and toluene.
When removing or installing soldered leads of
(4) Brush a thin coating on the component and
resistors, capacitors, transistors, and semi-
cure for 8 hours at 82 C (180 F).
conductor devices, a vacuum soldering method
4-19. Replacement of Regulator Section
must be used to prevent solder from entering
part.
(6) Polarized capacitors C2 (fig. 4-2 and 4-12), C3
through the holes in the regulator housing (54) as
(16), C4 (23), C6 (16), C7 (30) and C8 (15) must be as-
shown in figure 4-14. Be sure ventilation duct (56) is in
sembled to the printed wiring board (44) with the posi-
place.
tive ( + ) lead of the capacitor located as shown in figure
b. Secure the regulator housing with four screws (52
and 53). Attach bracket (51 ), using two screws (49), two
(7) All semiconductor diodes CR1, CR3, CR4, CR9
screws (48), and four flat washers (50).
CR11 (28) must be assembled to the printed wiring
secure to housing with three screws (43) and flat
board with the cathode lead located as shown in figure
washers (44); secure to front of regulator housing with
four screws (45), lockwashers (46), and flat washers
(47). Connect the A, B, C, D, and F leads from the
(8) After soldering, clean joints thoroughly with
generator section to their respective terminals on the
Lonco Flux Remover (HCR) within 4 hours after
back of the filter FL1. Also reconnect loose electrical
soldering operation.
lead to terminal A.
(9) Install transistors Q6, Q11 (fig. 4-2) and tran-
d. Replace terminal board TB3 (41) and secure with
sistor heatsinks (5) to printed wiring board (44) and
four screws (39) and flat washers (40). Replace ter-
secure with screws (2), flat washers (3) and nut and
minal links (18 and 19) in position shown in figure
lockwashers (4). Tighten nut and lockwashers (4) to a
torque of 5 to 6 pound-inches.
e. Replace shouldered stud (29), using lockwasher
(10) After assembling all components to the
(30), and flat washer (31). Slip insulated sleeving (28)
printed wiring board, apply conformal coating of
over stud, and wrap the long lead of capacitor C2 (22,
polyurethane EN-4 as described in b below. Apply
coating to both sides with the exception of those areas
forms choke L10.) Attach the leads to the terminals of
surrounding the mounting holes.
TB1 (12, fig. 4-6) using two bolts (23) four flat washers
b. Protective Polyurethane Coating of Voltage and
(22), one above and one below on each bolt, two lock-
Frequency Regulator 4B93-1-A.
washers (21 ) and two nuts (20). Be sure to engage lug
(1) Clean the component mounting area of the
terminal of capacitor Cl (15, fig. 4-6).
printed circuit board with denatured alcohol to be sure
of satisfactory adhesion of the coating to the board.
card assembly replacement, and then position circuit
(2) Clean the component soldered joints of the
card assembly (38) in regulator housing and secure
printed circuit board with Lonco Flux Remove HCR
with four bolts (36), and flat washers (37). Reattach
4-26
