Piper Dakota Maintenance Manual page 187

CHART 2401. TROUBLESHOOTING (ALTERNATOR) (cont)
Trouble
Zcro output indicated on
ammeter regardless of rpm
(refer to alternator system
test procedure). (cont)
Output indicated on am-
meter does not meet mini-
mum values specified in al-
ternator system test pro-
cedure.
PIPER AIRCRAFT
PA-28-236
MAINTENANCE MANUAL
Cause
Open field winding in al-
ternator.
Faulty voltage regulator.
1I2
Remedy
Disconnect field terminal of
alternator from field wiring
and check for continuity
from field terminal to ground
with ohmmeter (20-100
ohms) depending on brush
contact resistance.
—WARNING—
Turn magneto switch to OFF
before turning prop.
Pull propeller slowly by hand
turning alternator rotor
through 360° of travel.
If resistance is high, check
brushes for spring tension
and excessive wear and re-
place if necessary. If brushes
are okay and field reads
open, replace alternator.
Start engine, turn on load
(ref. alternator test pro-
cedure), set throttle at 2300
rpm. Check voltage at buss
bar (convenient check point,
remove cigar lighter and
check from center contact
(+) to ground (-). Voltage
should be l3.5-volts mini-
mum. If voltage is below this
value, replace regulator or
adjust to 14.0-volts using a
precision voltmeter con-
nected to bus.
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Page - 24 - 03
Reissued: August 1, 1986