Checking Voltage Regulator - Piper Dakota Maintenance Manual

Aircraft serial numbers 8611005 and up have an uncapped center
vent. Verify angled face of center vent is facing aft to ensure
positive airflow through battery box.
1. Remove box drain cap from under side of fuselage and drain off any electrolyte that may have
overflowed into box.
2. Clean battery and box. Corrosion effects may be neutralized by applying a solution of baking soda and
water mixed to a consistency of thin cream. Apply this mixture until all bubbling action has ceased.
3. Rinse battery and box with clean water and dry.
Check battery vent tubes for obstructions to ensure positive
airflow through battery box.
4. Check battery vent tubes for obstructions.
5. Place cap over battery box drain, if installed.
6. Reinstall battery.

CHECKING VOLTAGE REGULATOR

Ambient temperatures surrounding voltage regulator should be
between 50°F to 100°F while this test is being made.
The regulator is a fully transistorized unit. Field repair of unit is impractical, if it does not meet
specifications, it must be replaced. Test regulator as follows:
1. Be sure that battery is fully charged and in good condition.
2. Check alternator according to manufacturer's instructions to determine if it is functioning properly.
Test must be done with regulator out of circuit. After completing test, reconnect regulator into circuit.
3. Use a voltmeter with at least a 15-volt scale.
4. Connect positive voltmeter lead to red wire at regulator harness connector, or terminal block. Connect
negative voltmeter lead to regulator housing.
Do not connect voltmeter across battery because regulator is
designed to compensate for resistance contained within wiring
harness.
PIPER AIRCRAFT
PA-28-236
MAINTENANCE MANUAL
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Do not allow soda solution to enter battery.
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1J14
24 - 35 - 00
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Reissued: August 1, 1986