No sound coming from stereo - suspect amplifier is the cause
 

Hi all,

My stereo has never worked since I bought the car (Mk2 Mazda 6 hatchback) last year. The previous owner told me that one day it made a horrible loud noise and then the stereo stopped working (I'm imagining the noise was something like when you plug an electric guitar into an amplifier when it is switched on). The reason I think it is the amplifier that isn't working is that all of the stereo controls work - CD eject, disc playing time, radio station controls, aux input, volume control, etc, display on the dashboard indicate activity is normal - in the unlikely scenario that it blew all the speaker cones in the car then there would still be noise coming through, just not very clearly (I think).

I should say that I discovered the spare wheel well and side recesses (where the jack is stored and the one on the opposite side) were full of water due to a leak (which still needs to be identified and fixed) above the jack side recess (I can see drips coming from above it when it rains), which I have temporarily worked around by drilling a drain hole under the jack storage point - the wheel well is now dry, which suggests the water was filling the jack recess and overspilling into it. The point being that what I think happened is that water from the rear of the car sloshed forward under the carpet during braking, and found its way to where the amplifier is under the front passenger seat (driver seat if you're in a LHD car), causing some kind of short circuit and therefore blowing the amplifier (or hopefully just a fuse in the amp).

Is there anyway to verify that it is the amplifier at fault (other than buying a new amplifier and trying it out), and if so, can they be repaired, or does the internal circuit board get fried when they get wet?

Also, any suggestions for the source of the water leak would be great - my suspicion is that it might be at the panel seam between the roof and the rear panel at the top corner, under the tailgate lid (I've already siliconed the bolt holes for the support struts). A friend of mine suggested using flowable silicone to stop the leak when the source is identified - but it would be helpful to identify it, in case there is more than one.

Test a couple speakers to make sure they are function. You can find hundreds of on line video that can show you how I don't need to lay those steps out.

Based on your information it does sound like the amp portion of the sound system burned out. There are also ways to test that but those require removing the amplifier or component that has the power amp built into the complete unit and a little more technical diagnostic testing and experience. You would also need a digital volt/ohm meter.


Make sure before you use any seal and specifically if it is silicone that you understand read the information completely from the supplier to make sure what you are going to use it on. Silicone can cause the acieration of and start some metals to corrode.

Thanks for the pointers. I'll check out youtube for those videos you recommended.

I do have a digital multimeter, so should be able to follow video instructions for testing.

I've bought some sealant that is solvent free and non-corrosive, which a mechanic friend has said will be suitable.