Audio Systems: Stereo cuto out at high RPM, alternator output, voltage regulators

Question
Generally at fast idle it goes up to 18, but after warmup it goes back to around 13-14. Alternator is only a few months old.  Radio comes back on when I depress brake all the way, I imagine this because the power brakes are drawing power away?


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Followup To
Question -
I have a Sony in dash CD/stereo that is cutting out with high RPM or revving of the engine.  The alternator voltage reads real high during a fast idle, and then "settles down" after warmup at highway speeds.  The stereo will then work intermittently as long as the voltage reading stays low enough.  What can I do to fix this annoying problem?
Answer -
Tom,
When you say that the alternator output reads real high at a fast idle, how high does the voltage go? The problem may be with the alternator or with the voltage regulators inside the stereo.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net

Answer
Tom,
It sounds like the alternator is failing to regulate the DC output voltage. You should have the alternator replaced ASAP, or the over voltage can burn out light bulbs or damage to engine computer and other electronics in your vehicle.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net