My fisher price radio has a deveoped a high pitched wine which gets louder with the volume (at low volumes you can't hear it) and changes in pitch with the engine.
Common problem - likely to be the radio? or has a supressor (are there any?) fallen off in the engine bay?
Answers on a postcard (or just here will do!).
Cheers.
Yup, sounds like the supressor. Not sure where it is though. It cuts the inteference from the alternator i believe??? Which is why the noise rises and falls with the engine revs.
Sounds like an alternator diode failure. This won't affect your charging noticably but you can have the alternator tested for this failure by an auto electrician using an oscilloscope to check for excessive voltage ripple or spikes. A cheaper way would be to buy a ground loop filter.
Put the Fisher Price on Ebay and get £200 for it. Buy a new head unit which you can run your ipod off, like an alpine.
Phil
Quote from: "evileye_xc"a new head unit which you can run your ipod off, like an alpine.
dont get an alpine for ipod control, they're crap, really awkward to control
yep i had a similar problem on my previous car when i fitted an amp, but it was easy to cure with an inline filter of somekind.. (sorry can't be more specific as i didn't fit it...)
right here's your problem, you can fit a suppressor but it wont cure all the problems as a single suppressor wont stop all the spectrum of frequencies. Modern radio's get around this by varying the value of the suppressor as you move across the rpm range, so just adding the single value suppresor wont stop all the frequencies it will only help a bit
you need to work out the suppressor value based on mid range rpm and convert that to the frequency, that will give you the correct suppressor
3500 RPM = 58.333Hz
Quote from: "evileye_xc"Put the Fisher Price on Ebay and get £200 for it. Buy a new head unit which you can run your ipod off, like an alpine.
Phil
Only got £99 for mine last week s:? :? s:?
I can offer there are usually three ways alternator whine is induced in car audio.
1. stv2100 has already mentioned a leaky diode. The test for this is to put an oscilloscope across the alternator leads and watch for the transient spikes that lead to whine. Ultimately, this can lead to shortened life of electronic components if the component itself does not have a good filtering system.
2. Poor grounding scheme. This is usually referred to as a ground loop. It happens when one component's ground is at a different potential from another in the audio chain. The fix is to make sure all audio components share a single ground (aftermarket equipment usually - amp/headunit, processors, etc.).
3. Poor layout of signal cables from the headunit to an amp (aftermarket usually). In the US version of the Spyder, there's a set of OEM wires running down the channel under the driver's side door sill that has some strong transients on it that get into the signal cable if it is also routed there. The fix here is to route the cables down the other side (Driver's side in the UK - assuming the wiring harness is the same) or down the middle.
If you have no add-ons, i.e., still the factory stereo setup, I suspect stv2100 had the solution. In the US I would recommend dropping by a car electrical repair shop - not sure if you have such places (specializing in alternator/generator repair).
A suppressor does as it says, suppresses. Which means it also has an adverse effect on the good signal as well (it will suppress the part of the music that has the same range as the whine it is suppressing).
Good luck.
Thanks all. I'm still under warranty so will get it checked out at the next service. It's not too bad as I write, only noticable at the moment when listening to speech radio at louder volumes (due to working engine at higher revs, hence more volume required... arrgh Catch 22!)
Cheers.
Quote from: "adetri"Thanks all. I'm still under warranty so will get it checked out at the next service. ....
A caution if you will. Assuming stv2100 has made the proper diagnosis, I expect the dealer will not honor a warranty claim (unless you have a wonderful dealer).
Why? Because with a single bad diode the alternator will still produce adequate amperage/voltage to keep the car running and battery charged.
The real issue is if you install some sensitive electronics, without adequate filtering, you can damage them. An example would be a video monitor in a Navpod - directly wired into the electrical system (say through the cigarette lighter plug).
I'm not posting all this to make you paranoid, just to alert you if they refuse service. The only way I know a bad diode can be diagnosed is through use of an oscilloscope - a "normal" alternator tester will show the unit "OK".