M3 + Lead
5 Place new transistor on circuit
board. Make sure emmiter, collector, and base leads
Failure of the unit to meet adjustment
are positioned as noted during removal.
requirements is indicative of a defective reg-
6 Solder transistor in accordance
with MIL-STD-454 Requirement 5. Trim transistor
(10) After all adjustments have been made,
apply a locking compound (P/N MIL-S-22473
GRHVV, FSCM 80244) between the adjustment
screw head and housing surfaces adjacent to screw
(1) Check that red, black, and white jumper
wires are properly positioned for the generator output.
f. Cleaning, Inspection, and Repair.
(1) Clean voltage regulator with compressed
(a) MEP-026A (28 VDC) - Red jumper
air and a soft bristle brush.
wire is connected to terminal C4, Black jumper wire is
connected to terminal C6, and the White jumper wire
(2) Inspect voltage regulator for cracks, dam-
is connected to terminal C1.
aged terminals, or other visible damage.
(b) MEP-021A (400 Hz) - Red jumper is
(3) For testing, refer to step d. Testing.
connected to terminal C4, Black jumper wire is con-
nected to terminal C6, and white jumper wire is con-
(4) Repair of components identified by test-
nected to terminal C1.
ing as faulty is by component replacement.
(c) MEP-016A (60 HZ) - Red jumper
wire is connected to terminal C3, Black jumper wire is
Solder joints and/or component leads
connected to C4, and white jumper wire is connected
(except potentiometer leads) should not pro-
to terminal C1.
ject more than 0.125 in. beyond the surface
of the board.
(a) Transistor replacement:
1 Make sure that replacement tran-
(3) Use tags for identification to connect
sistor has same identification number as the original
leads to voltage regulator.
2 Apply heat sinks to the circuit
board runs connected to the transistor being replaced.
a. General. The frequency converter used on
Model MEP-026A/C is a sensing unit for a tachometer
3 Note and record position of tran-
which indicates the revolutions per minute (rpm) of
sistor leads and tab on transistor case in relation to the
printed circuit board.
Models MEP-016A/C and MEP-021A/C is a sensing
unit for a frequency meter which indicates a frequency
4 Unsolder transistor from circuit
of 60 hertz or 400 hertz.
board and remove.