Alternator A/C voltage question

[Bmwe5320023.0]

If someone can measure their A/C voltage out of the alternator, I'd really appreciate it! Will tell me if I need to consider replacing the alternator!

[EODguy]

Just on the off chance...

I had a similar problem and it was actually the radio function running in the BACKGROUND since these units go all over the world the radio station frequency ranges alternate between compatible and not, giving you a guaranteed static channel every 1/2 megahertz or something.
I deleted the automatic radio start up and haven't heard it since.

Sent from my SM-A730F using Tapatalk

[80stech]

Originally Posted by Bmwe5320023.0

If someone can measure their A/C voltage out of the alternator, I'd really appreciate it! Will tell me if I need to consider replacing the alternator!

Every multimeter will give you a different and inaccurate reading so measuring isn't going to help much. You have the new low noise alternator coming so you might as well use it.

[wpoll]

Originally Posted by Bmwe5320023.0

If someone can measure their A/C voltage out of the alternator, I'd really appreciate it! Will tell me if I need to consider replacing the alternator!

I can grab an oscilloscope and get a screen-shot of the output waveform but unless you can do the same, it won't help much.

[andrewwynn]

A good DMM will show two things: 1) the AC over dc
2) the frequency.

When one of the three diode banks starts to fail you will get a much larger AC component, that's what's being asked here.

[andrewwynn]

If you want to eliminate AC interference from radio simply remove the serpentine belt. No alternator no hum

[Bmwe5320023.0]

Originally Posted by EODguy

Just on the off chance...

I had a similar problem and it was actually the radio function running in the BACKGROUND since these units go all over the world the radio station frequency ranges alternate between compatible and not, giving you a guaranteed static channel every 1/2 megahertz or something.
I deleted the automatic radio start up and haven't heard it since.

Sent from my SM-A730F using Tapatalk

I actually deleted the radio module from the vehicle completely, as well as the antenna. I think it's not possible to have a radio at all in the car anymore!

[Bmwe5320023.0]

Originally Posted by wpoll

I can grab an oscilloscope and get a screen-shot of the output waveform but unless you can do the same, it won't help much.

If you post your oscilloscope, I'll gladly buy the same make and model and repeat the test!
I feel with how deep I got into DIY stuff with my cars, owning an oscilloscope would not be unreasonable !

[Bmwe5320023.0]

Originally Posted by andrewwynn

A good DMM will show two things: 1) the AC over dc
2) the frequency.

When one of the three diode banks starts to fail you will get a much larger AC component, that's what's being asked here.

Exactly Andrew!
I'm just trying to get some values to compare.
To know if diodes, rectifiers etc. are bad in my alternator.
I mean it's not a big deal to buy a new alternator and test it out this way, by just swapping the parts.
But for me the spirit of this forum is to learn how to test components, instead of just going through replacing parts mindlessly. I mean it won't hurt my car to get a new alternator lol...but would be nice to at least have some measurement to compare.

[wpoll]

Originally Posted by Bmwe5320023.0

If you post your oscilloscope, I'll gladly buy the same make and model and repeat the test!
I feel with how deep I got into DIY stuff with my cars, owning an oscilloscope would not be unreasonable !

FWIW, it's a Fluke 123 Scopemeter but any 'scope will produce the same test results - even a cheap add-on for a smart phone.



https://www.amazon.com/Oscilloscope-.../dp/B07TB8V2X1