Audio Systems: Pioneer Car Cd/Radio, amp fuse, expert diagnosis

Question
Recently purchased Pioneer Car Cd/Radio which I
installed myself, it worked fine for a couple of
days, then somehow some form of short circuit
occurred which seems to have maybe spoofed the
Amplifing MOSFET I.C. on the back panell of the
Radio! Basically the unit it's self lights up,
the Cd Player accepts a Cd and operates as if it
is playing that Cd.

All that's missing is the Sound from the
Speakers!

I would appreciate your expert diagnosis, I accept my prempted diagnosis may be incorrect.

Interestingly there's no sign that the 10 Amp
fuse blew, it seems to look perfect.

Thank you for reading this, I appreciate your
diagnosis, If I need to seek a repair shop here
in N.Z. I'm not gonna be ripped off.

Kind regards,
Peter.


Answer
Hello peter,
Great to hear from you in N.Z., I'm located in the USA in the state of Maryland. As for your radio unit, I would say that you may have connected the speaker wires incorrectly. On a high powered output stereo you cannot ground any of the speaker wires or certain damage to the audio output amp will result. Also you cannot cross connect the speaker feeds and returns. A little note, depending on what type of vehicle you have, some car makers will groung one side of the speaker wire/s to the car frame? On several vehicles that I have recently looked at after the radio failed after the owner self installed (2 units) I located the cause of the problem. I found that the kick panel trim along the floor where the owner ran the speaker wires was pinching and shorting out one of the speaker wires. If you have a VOM, unplug the connector from the radio and look for a short to ground in one or more of the wires.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net