BMW Repair: Radio, ohm meter, wire connectors

Question
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Followup To
Question -
I own a 1996 328is.
The radio suddenly gave up this morning. The display is lit but i have no sound from it. I had this same problem about 2 years ago and it had no sound for about 3 months but then just started working agiin. The system is factory fit, HK speakers and the usual trunk mounted amp. My trunk mounted CD changer display on the dash also lights up but no sound from that either. Is it likely an amp problem?
Answer -
It sounds to me like the amp has a bad ground or a faulty connection.  You could test this by plugging a speaker directly into the "head unit out" and see if the pre-outs are sending any signal at all.
-cheers

I have not tried a speaker on the head pre-outs yet but when i pulled the head unit from the dash, i can hear very faint music from within the head unit when it is switched on. I also checked the ground from the amp and it seems OK (I used an Ohm meter which showed no resistance to ground). I have checked all the wire connectors too which seem fine. Any new ideas?

Answer
I would suspect something internal on the amp unless the signal the amp is getting is corrupted by sporadic wire grounding between the amp and speaker or amp and head unit.  i think some stereo installers have a repair/testing facility you could take the amp to.
-cheers