Hey everyone,

I have a question regarding the stereo and alternator.

Sometimes when the car idles my radio goes on and off, when i rev the power or start driving, it comes back alive and all is fine.

Can this happen with a bad alternator? How do i test my alternator?

Also, when the volume is up high and there is no music I can sometime hear a whining pitched sound that changes with the RPM through the speakers.

 

Hey thanks everyone for all those great reactions! Awesome ;-)

I found out myself how to test the alternator.

I placed this special testing equipment, it shows me the alternator has spikes. 1sec its charging, the other sec nothing. Guess its time for a rebuild!

 

Might want to mark your crank damper while you're in there messing with the drive belts....make sure your alternator is really being properly driven.....

 

Thanks for bringing that to my attention! I will have a look if its slipping.

 

Usually they'll make a short, high-pitched chirp on cold start when they start to delaminate.......before you start having charging problems...but marking it takes no time at all and then you can always tell just by looking.

 

Well, I test it with equipment directly at the alternator, showing me those spikes.
When i test with multimeter in the boot at the battery, turning on my equipment lights, blowers, radio etc it drops down to 11.95 Volts.