Section V. LEECE-NEVILLE MODEL R0015027RD

TB 9-2920-225-34-1

Section V. LEECE-NEVILLE MODEL R0015027RD

Failed devices have been successfully replaced

3-10. General. Figure 312 is a plan view of the

with part number 71590WT-100 by performing

regulator with the cover removed, showing the

some minor mechanical modification.

heat sink and the circuit board. The components

Globe-Union Inc. FSCM 71590

are indicated by their reference designations, and

Centralab Electronics Div.

on the circuit board the terminals are associated

Hwy. 20 W. P.O. Box 858

wire colors are also indicated. Figure 313 is a

Fort Dodge, IA 50501

plan view of the regulator with the cover, heat

(10) Place positive ohmmeter probe on TP15

sink and circuit board removed, showing the relay

and negative probe on TP16. The reading should

and remaining components. The components are

be greater than 10 ohms and less than 100 ohms;

indicated by their reference designations, and test

if not, replace D3.

points 1 through 5 are shown. Figure 3-14 is a

b. Resistor R10.

plan view of the regulator with the cover removed,

(1) Place ohmmeter probes on pins D and E

showing test points 6 through 18. There are 18

of connector J2. Meter should read approximately

total test points. Figure 3-15 is an electrical sche-

0.4 ohms.

matic diagram of the regulator circuit.

(2) If other readings are obtained, replace

resistor.

3-11. Checkout and Repair.

c. Resistor R9.

a. Relay (see Figs. 313 and 314) (power dis-

(1) Place ohmmeter probes on TP5 and pin

connected).

C of connector J2. Meter should read 0 ohms plus

(resistor is actually rated at 0.05 ohms).

(1) Place positive probe of ohmmeter on pin

F of connector J2 and negative probe on TP1

(2) If other readings are obtained, check the

(white/yellow wire). Meter should read low ohms

wiring from the bottom terminal of the resistor

to pin C on connector J2. If the wire continuity is

(hundreds).

good, replace the resistor.

(2) Reverse probes. Meter should read high

d. Detailed Circuit Checks. Table 35 contains

ohms (thousands).

"power off" resistance checks of the circuit (see

(3) If other readings are obtained, see de-

figs. 312, 3-14 and 3-15 for test points).

tailed circuit check below.

(4) Place ohmmeter positive probe on TP2

e. Functional Check. Check the performance of

the regulator on the test stand and make final volt-

and negative probe on TP1. Meter should read

approximately 50 ohms.

age adjustments. Voltage output should read 28

volts. If the regulator does not function properly,

(5) Reverse probes. Meter should read low

perform the following:

ohms (more than 10 and less than 100).

(1) Check wires and connections.

(6) If other readings are obtained, discon-

(2) Replace cover assembly.

nect the WHT/YLW wire on TP1 and repeat (4)

(3) Perform bench test procedures.

and (5) looking for a meter reading of 40 to 60

ohms in each case. If other readings are obtained

NOTE

replace the relay, NSN 594500-409-3883. Re-

place the WHT/YLW wire on TP1.

After final repair, check regulator on the

(7) Place ohmmeter probes on TP3 and TP4.

test stand.

Meter should read infinity (open circuit). If other

If the regulator still noes not function correctly

readings are obtained replace the relay, NSN

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

5945-00-409-3883.

each component. All the parts should be checked

(8) Place positive ohmmeter probe on TP17

with an ohmmeter and the capacitors checked with

and negative probe on TP8. The reading should

a capacitance meter. The circuit board traces

be greater than 10 ohms and less than 100 ohms;

should be checked with an ohmmeter to ensure

if not replace Ql, NSN 5961007303284.

that there are no cracked traces. Traces with

(9) Place positive ohmmeter probe on TP12

hairline cracks will show as good at lower tem-

and negative probe on TP13. Rotate the potenti-

peratures and will tend to show open circuit at

ometer. Full counterclockwise should be 0 ohms,

higher temperatures. If the board seems good at

gradually increasing to 100 ohms at full clockwide.

room temperature, but the regulator still fails,

If not, replace the potentiometer. The potenti-

this could be the cause.

ometer is a 100 ohm, 2 watt, tab-mounted device.

3-15