Section III. LEECE-NEVILLE MODEL R0015027RB

TB 9-2920-225-34-1

Table 32. Voltage Checks (Power On--Model 5027RA-continued

Section III. LEECE-NEVILLE MODEL R0015027RB

3-6. General. Figure 36 is an exploded view of

(2) Place ohmmeter probes to terminals of

the regulator, listing the major subassemblies.

the rheostat (see fig. 3-7).

Figure 37 is a plan view of the box and an under-

(3) Rotate rheostat fully clockwise, reading

side view of the cover, showing the interconnect

shoud be approximately 45 ohms.

wiring.

(4) Rotate rheostate fully counterclockwise,

reading should be less than 5 ohms.

3-7. Checkout and Repair.

(5) If other readings are obtained, replace

a. Diode and Relay (power disconnected).

the rheostat.

(1) Place positive probe of ohmmeter to pin

F of connector J2 (see fig. 3-7).

d. Transistor and Circuit Board. If no faulty

(2) Place negative probe to top connection of

components were detected after performing tests

diode CR2, (see fig. 37). Meter should read O

a, b, and c, replace the cover assembly (see fig.

ohms.

3-7) .

( 3 ) Place negative probe to TP1. Meter

should indicate low resistance.

NOTE

(4) Reverse probes. Meter should indicate

After final repair, check regulator on the

high resistance.

test stand.

(5) If other readings are obtained, replace

diode CR2.

If the regulator still does not function correctly

(6) Move negative probe to pin C of connec-

it will be necessary, if local skills permit, to test

tor J1. Meter should read approximately 55 ohms.

each component. All the parts should be checked

with an ohmmeter and the capacitors checked with

(7) If another reading is obtained, replace

a capacitance meter. The circuit board traces

relay (see fig. 37).

should be checked with an ohmmeter to make sure

b. Power Resistor. Place ohmmeter probes

there are no cracked traces. Traces with hairline

across power resistor R1 (see fig. 37). Meter

cracks will show good at lower temperatures and

should read approximately 40 ohms.

will tend to show open circuit at higher tempera-

c. Voltage Adjustment Rheostat.

tures. If the board seems good at room tempera-

ture, but the regulator still fails, this could be the

(1) Remove voltage adjustment access screw

cause.

from the cover of regulator.

3-7