OTC 3131 MinuteMan Plus Multi-Purpose Electrical System Checker
Tests batteries, alternators, regulators, and starters. Direct-from-battery tachometer feature gives RPM readings without complicated hookups to ignition system. Also, ammeter/voltmeter capabilities. Evaluates discharged or charged batteries in one minute. Tests all 12-volt automotive and heavy-duty batteries with cold cranking amp ratings of 100-1500. Has its own internal battery; no external power source needed.Checks charging system at high RPMs and at idle, and stores the data. Results show regulator volts, peak amps, and diode condition. Utilizes wave form analysis when testing alternator diodes; more accurate than 'ripple voltage" tests. Displays cranking volts and amps, indicates either "Good Starter" or "Bad Starter."