John Deere stx38 - Manual (Page 130)

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3/21/97
CIRCUIT OPERATION AND DIAGNOSIS ELECTRICAL
CHARGING CIRCUIT DIAGNOSIS STX30 & STX38 (SN —210000)
Test Conditions:
• Park brake engaged • Engine running at fast idle
• Transaxle in neutral • Meter negative (-) lead on battery negative (-)
• Regulator/rectifier connector disconnected • Meter positive (+) lead on numbered test point
• Key switch in run position
Test/Check Point Normal If Not Normal
1. Battery positive terminal. 11.8—13.2 volts Test battery
2. Regulator/rectifier connector. Minimum unregulated voltage
output—28 VAC. Check flywheel magnets, if OK
replace stator.
Test Conditions:
• Regulator/rectifier connector connected
Test/Check Point Normal If Not Normal
3. Regulator/rectifier center
terminal.
Battery voltage Check battery positive cable
connections, and 210 red wires.
4. Regulator/rectifier wire. Minimum regulated output—
13 amps at 12.2—14.7 volts
Voltage must stay below 14.7 volts. Replace regulator/rectifier.