TM-9-2320-280-34

TRUCK, UTILITY: M998 SERIES

TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE

JANUARY 1996

TM-9-2320-280-34 - Page 386 of 1258

6±-±5±

.±2±

. 400 AMPERE DUAL VOLTAGE ALT±E±R±N±ATOR (12469057) TESTING AND REPAIR (Cont'd)

TM 9-2320-280-34

Change 1

6 - 4 4 . 1 7

26.

Perform regulator bypass test. Prepare alternator as in full-load test.

NOT E

• Perform this test only when instructed from tables 6-H and 6-I.

• Use jumper wire rated for 15 amps.

27.

Disconnect alternator connector from regulator. With alternator spinning, use jumper wire and short

pin A to ground momentarily. Record results.

28.

Amperage should rise within ±10 percent of rated value with jumper wire connected, and fall with

jumper disconnected. Refer to table 6-K, Regulator Bypass Test, for diagnosis.

CONNECT

DISCONNECT

DIAGNOSIS

AMPS RISE

AMPS FALL

Alternator OK. Replace regulator only if low

AMPS (160-238)/low VOLTS (21-25) are

indicated in table 6-H and/or table 6-I.

NO CHANGE

NO CHANGE

Alternator must be repaired. Refer to static

testing, task c.

Table 6-K. Regulator Bypass Test.

29.

Turn test stand master power switch and load switch to OFF.

30.

Disconnect jumper wires from terminals on test stand and alternator.

31.

Remove belt from test stand pulley and alternator pulley. Remove alternator from test stand.