Radio makes battery go dead

[LittleBlackCar]

Hi, for the past year I have had the radio fuse out of my car, otherwise my battery goes dead within 30 hours of the car not being driven. I know when the car is turned off every 20mins or so, I hear a very loud popping sound from the speakers or radio, and then its quiet. Any idea how to isolate the problem further? I'd like to buy a new head unit, but it might be speakers or something else.
The auto electricians (x2 different companies), sisters husband and mechanics tell me I'm wrong and I couldn't possibly know, but within 2 days of re-inserting the radio fuse, my battery is on charge tonight. I've gone a year without a flat battery... Any help is muchly appreciated!

 

[Handy Andy]

It will need to be investigated more. So the Head unit and the interface to the main console - if a cap has shorted out - you hear popping - from the stray spikes and wire motions - usually means you also have a shorted input cap where now the power to the internal amplifiers that use that cap to keep their voltages inside are now leaking out and pretty much powering things or drawing current thru speaker coils into the ground - killing the battery.

So you'll need to check the wires to make sure the DVM (Digital Volt-Meter) is on DC and your car is not sending DC power into the speakers - only AC - so the DC part of the DVM shoudl be at zero - so use the 20V setting at first to see if power is lost to the speakers, then go to a smaller range to see if the power voltage can be determined directly - it may help you find the side channel that is causing this and might be able to get it to a shop or DIY to fix and restore that isolation so you don't kill your battery.

 

[LittleBlackCar]

Thanks for this, I will ask a friend to help with this 😊
Muchly appreciated