Pic. 7.26. Scheme for checking the conductivity of the contacts of the rectifier unit
Connect the negative probe of an ohmmeter to the positive terminal of the rectifier unit, and connect the positive probe in series to each of the other three terminals. Check for conductivity (closed circuit) in all three dimensions (pic. 7.26).
Reverse the polarity of the tester probes and repeat the first procedure. Make sure the circuit is open in all three dimensions (resistance tends to infinity).
Check negative valve.
Connect the positive probe of the ohmmeter to the negative terminal of the rectifier unit, and connect the negative probe in series to each of the other three terminals. Check for conductivity (closed circuit) in all three dimensions.
Reverse the polarity of the tester probes and repeat the first procedure. Make sure the circuit is open in all three dimensions (resistance tends to infinity).
If test conditions are not met, replace the rectifier unit.