is it fried? 12v down rca grounds.

I sent 12V down all four RCA grounding shrouds on a factory iPod integration solution I was building. How can I tell if my devices are fried? The devices in question are a PIE MPSS4 source switcher, a PIE RCA-POD iPod integration cable, and the 1993 Volvo 240 factory external 12 Watt (?) amplifier. PIE is Precision Instrument Electronics, a car audio adapter manufacturer.

I had the setup connected for about 5 minutes with 12V going down the RCA grounds. Here's what I found:

Factory radio - I smelled burnt plastic when I removed it. When I opened it, the areas around the audio solder connections, and some pins on the "main audio chip", appeared damaged. The radio still works, but the balance and fader knobs are out of whack.

iPod nano G1 - It continued to work, play music through headphones, upload songs from the computer, and even upload new firmware. But the iPod would no longer charge. And when I connected it to the iPod factory integration I was testing in a 2004 Volvo XC70, it freaked out reporting that it was incompatible and generating horrible hum. But, underneath the hum, the audio was quietly playing. Eventually the battery died, would not charge, and I exchanged it at an Apple Store for a refurbished one.

Factory amp - Still works, with the damaged factory radio attached.

Would the other components have suffered since 12V passed through their audio channels? Might the damage on these components cause more damage to my new replacement components? ie: audio wires melted together causing shorts, etc?

Thanks for your help.

As far as damage to the components goes it sounds like you answered your own question. With the wiring I would reccomend inspecting every inch of it for damage. Even the slightest bit of damage can become worse in the unfriendly environment of a car. I would not be surprised if there were new wires in your future. 

That was really dumb, but i guess you already knew that

I'm not really sure how to check for damage from sending 12V down the RCA grounds. The 12V was simply passing through the MPSS4 and RCA-POD, not actually "stopping and being used" like at the radio and iPod. Maybe those devices passed it with no problem. I even wonder if the amp passed the high voltage on to the speakers (sure sounded like heck when I had it connected, but I don't think the speakers are fried).

Is there some electrical rule about the consequence of sending higher voltage through components expecting low voltage? ie: would it hurt to send 12V through 24 guage RCA wires?


For the record, this happened because I was creating a custom adapter to convert the stock radio to RCA outputs. Its 6 pin DIN connector had 4 RCA + leads, a shared ground, and 12V all close together. My horrible soldering skills and the cramped connector must have mashed ground against 12V, but only intermittantly; it didn't show during my tests.