The SYNCHRO-TESTER ZEROING METHOD is potentially less accurate than the voltmeter or
electric lock methods. This is because the dial on the tester is difficult to read and may slip from its
The synchro tester is nothing more than a synchro receiver on which a calibrated dial is mounted.
The tester is used primarily for locating defective synchros but does provide a method for zeroing
TROUBLE INDICATORS are signal lights used to aid maintenance personnel in locating synchro
trouble quickly. These lights are usually mounted on a central control board and connected to different
synchro systems. The lights indicate either overload conditions or blown fuses.
SYNCHRO TROUBLESHOOTING is the locating or diagnosing of synchro malfunctions or
breakdown by means of systematic checking or analysis. This is done by using trouble indicators, trouble
tables furnished by manufacturers, known operating voltages as references, and synchro testers.