Hi - I fitted a CMD310 into my Porsche Boxster this evening.

Since doing so, I have interference - a whining noise which the pitch increases with engine speed.

This is strange because the Becker unit which I removed never exhibited any interference at all! Also the Becker unit had no ferrite rings or supressors fitted to the wiring, just like the Philips unit.

What can I do to try and eliminate this unwanted noise? Is the unit faulty?

Would really appreciate an answer from a Philips technician.