My car has had some electrical issues and made a bad burning smell the other day. I've taken the head unit out today and the smell is definitely coming from in the head unit.

Is it possible for a head unit to spontaneously fry its own components or is there a bigger issue that has caused this?

My car is 2005 Mk2 Ford Focus with the sony 6000CD head unit.

I've had two home AV receivers fry because of a dodgy electrical input (the first time it happened I assumed it was just the amp, second time it happened to a different amp on the same extension lead so I binned it and only use surge-proof extensions), so it's definitely possible for them to fry themselves, but if you've been having electrical issues you might want to get it tested before you fit another radio, otherwise it could fry in the same way.

It could of course just be that the 6000CD unit was on the way out anyway, so it's up to you how you want to proceed. If you know anyone who has a voltage tester that'd be a good start.

Thanks very much Benedict, I've ordered a second hand one but I'll do some checks before i plug it in

It's probably the amplifier you're smelling. I've blown a couple of them in my time (proper amps used in theatres/cinemas, not the ones in cars).

Usually caused by putting too much power through it, or something shorting out inside.

Thanks Luke, where would i test the voltage to make sure too much isn't getting through? On the battery?

I have no idea sorry, I'm a mechanical fitter rather than electrician. I just happen to know about amplifiers from when I worked as stage crew in a theatre.