Schumacher PST-900X - Manual (Page 8)

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HIGH CHarGING VOLts WHeN at IdLe: the voltage output from •
the alternator to the battery exceeds the normal limits of a functioning
regulator. Check to ensure there is no loose connection and the ground
connection is good. If there are no connection problems, the regulator
may need to be replaced, have it checked. since most alternators have
the regulator built-in, this may require you to replace the alternator, have
it checked. the normal high limit of a typical automotive regulator is
14.6+0.05 volts. Check the manufacturer’s specifications for the correct
limit, as it will vary by vehicle type and manufacturer.
after you are through with testing the charging system at idle, press 9.
eNter to test the charging system with accessory loads. the display
screen will show turN ON LOads aNd Press eNter. turn on the
blower to high (heat), high beam headlights and rear defogger. do not
use cyclical loads, such as air conditioning or windshield wipers. Press
eNter to continue.
NOTE: When testing older model diesel engines, the users need to run the
engine at 2500 rpm for 15 seconds. the display screen will show ruN tHe
eNGINe uP tO 2500 rPM 15 seC.
the tester will test the amount of ripple from the charging system to the 10.
battery. One of the three following results will be displayed along with the
actual reading measured.
rIPPLe deteCted NOrMaL: the diodes are functioning properly in •
the alternator/stator.
NO rIPPLe deteCt: the diodes are functioning properly in the
•
alternator/stator.
rIPPLe deteCted HIGH: One or more of the diodes in the alternator
•
are not functioning properly or there is stator damage. Check to ensure
the alternator mounting is sturdy and that the belts are in good shape
and functioning properly. If the mounting and belts are good, the
alternator may need to be replaced, have it checked.
Press eNter to continue testing the charging system with accessory 11.
loads. One of the three following results will be displayed along with the
actual reading measured.
aLt. LOad VOLts HIGH: the output voltage from the alternator to the •
battery exceeds the normal limits of a functioning regulator. Check to
ensure there are no loose connections and that the ground connection
is good. If there are no connection problems, the regulator may need to
be replaced, have it checked. since most alternators have the regulator
built-in, this may require you to replace the alternator, have it checked.
ALT. LOAD VOLTS LOW: The alternator is not providing sufficient current
•
for the system’s electrical loads and the charging current for the battery.
Check the belts to ensure that the alternator is rotating with the engine
running. If the belts are slipping or broken, replace the belts and retest.
Check the connection from the alternator to the battery. If the connection
is loose or heavily corroded, clean or replace the cable and retest. If the
belts and connections are in good working condition, the alternator may
need to be replaced, have it checked.
aLt. LOad VOLts NOrMaL: the system is showing normal output from
•
the alternator. No problem detected.
Press eNter and the display will show test OVer, turN OFF LOads 12.
aNd eNGINe. Press eNter to continue.
turn off all accessory loads and the engine. Press eNter to continue.
13.