Regulator-Rectifier Diode Failure Q&A

Not all regulator-rectifiers are the same, and their diodes can fail in various ways. The best way to diagnose diode failure on a regulator-rectifier is to bring out a digital multimeter and test the unit. 

Powersports pro John Talley goes live on our YouTube channel every Friday at 3pm Eastern, and in this edition, one viewer wanted to know what the most common type of diode failure is on regulator-rectifiers. Here's what John had to say about diode failure on a voltage regulator-rectifier.

Regulator-rectifier diode testing

Regulator-Rectifier Diode Failure

What is the most common type of diode failure on a regulator-rectifier?

John Talley: They can fail in so many different configurations as far as which diodes go out and which ones are still operational. Plus, the way the actual charging system or the way the regulator-rectifier may be designed. The simplest one of course is where you’ve got a series of diodes either on the forward or reverse bias configuration to change your waveform from, of course an AC waveform to a DC. I know that I did a pretty in-depth video explaining 3 different manufacturers’ regulator-rectifiers — one from Honda, one from Yamaha and one from Polaris — and I went through what the differences are on those and how to test all three. Some like the simpler one, like the Honda, yes you can actually get in there and use your multimeter to do a reverse and forward bias test of each individual diode. But as the regulator-rectifiers become more complicated, it’s harder and harder for you to look through that narrow window with your multimeter to test them effectively.  

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As John mentioned, regulator-rectifiers can fail in a variety of ways, and they're not all designed to work the same way. Testing a regulator rectifier is one way to diagnose issues with a powersports vehicle's charging system. In the video below, John demonstrates how to test regulator-rectifiers from three different manufacturers: Honda, Yamaha and Polaris. They're not all the same, but the tests John performs on various manufacturers' regulator-rectifiers will help you get an idea of how these ignition system parts work and how to diagnose problems with them.

Watch the video below to see how to test Honda, Yamaha and Polaris regulator-rectifers.

Want to see more live repair questions answered? See more motorcycle and ATV repair questions answered here.  



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