Test Lamp Method
With rectifier end shield and stator assembly separated, test rectifiers with a 12V battery and suitable test lamp (No. 67 bulb, 4 candle power). Connect test lamp to battery positive terminal and to one test probe. Touch other test probe to battery negative terminal. Measure rectifier continuity with probes touching heat sink and rectifier top strap. Then reverse probes. If lamp lights with current flow in one direction only, rectifier is satisfactory. If lamp lights with probes either way, rectifier is shorted. If lamp does not light at all, rectifier is open. Test each rectifier and both assemblies in same manner.