car radio powers up but no sound

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=115902
Printed Date: May 15, 2024 at 1:14 PM

Topic: car radio powers up but no sound

Posted By: jasperjodo
Subject: car radio powers up but no sound
Date Posted: August 25, 2009 at 12:13 PM

Hello

Friend's 1990 Geo Metro, 2 dr hatchback, Canada

factory 4 speaker system

Aftermarket cassette/radio powers up but delivers no sound. Owner claims radio stopped working after high school mechanics' class changed her brakes (5 yrs ago). I offered to look at it. Retrieved Chilton book from Library to review wiring diagram. Radio seems to be hooked up correctly. I swapped her radio out with an old one I had (also a cassette player / radio) and wired mine to the correct speakers etc. and it did the same thing.

I own a Fluke DMM multitester and checked the radio's 1 amp fuse (good). Car fuses also okay in the fuse box.

I removed, cleaned (although it did not seem to need it), and reattached the chasis ground from the battery.

I am losing sleep over this one. Can anyone help?

Thanks!

Jasper

Replies:

Posted By: DYohn
Date Posted: August 25, 2009 at 12:44 PM

Check continuity from the head unit to the speakers, and check to make sure a speaker or speaker wire is not shorted or shorted to ground.

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Posted By: jasperjodo
Date Posted: August 25, 2009 at 1:17 PM

Thanks for your response.

Any chance you'd want to explain how I do those steps? I'd hate to think I'm doing it correctly when if fact I may not be... I'd really like to fix this for her because I'll score big points if I do!

Thanks again

Jasper

Posted By: DYohn
Date Posted: August 25, 2009 at 2:09 PM

You need an ohm meter, and maybe some long leads. Disconnect the speaker wires from the head unit. Pull the speakers out of the doors and check the speaker wires point to point for continuity - each wire should read less than one ohm usually. Then check positive to negative with everything unhooked and it should read open loop. While you're there, check resistance to ground. It should be an open loop from each wire to chassis ground. Also check the DC resistance of the speakers. They should be greater than 1.5 ohms, usually, and less than 4 ohms for 4-ohm speakers. You'll need to do this at each speaker. Any of them shorting positive to negative or shorting to ground will cause the head unit to shut off the output amplifiers.

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Posted By: jasperjodo
Date Posted: August 25, 2009 at 2:37 PM

Thanks for the explanation. I will check this out and post back results tomorrow.

Jasper