Hello, I've got a 2005 MCS with the H/K system, the stereo would light up but no sound when I first bought it a week ago and the battery would drain overnight. Decided to pull the amp and the head unit after researching a bunch on here. Got a wild hair and took the amp completely apart and cleaned all contacts and solder connections on the entire circuit board. Decided to try and hook everything back up and with the head unit plugged in hanging out of the center dash and the amp sitting in the cargo area NOT mounted, it WORKED. I was pretty surprised and while I was immediately excited to take credit for the fix, I still needed to correctly install everything. Once everything was bolted up in their respective positions, NO WORKY. Decided to pull the amp out again but leave the connector on and it worked again. My question is, has anyone ever seen an issue where the amp did not like the case being grounded? After making a completely rigged isolation bushing out of plastic tube and popsicle sticks (Yes I'm serious) the amp works while installed however, if the case makes contact anywhere, it mutes the radio and seemingly puts an inherent draw on the battery. Pretty confused because in my electrical experience if a ground is not present, the system isn't usually happy with it. I'm very curious if people are also misdiagnosing failed amps for this reason OR if mine is on the way out due to this weird grounding unhappiness.

See below:




Any experienced input is welcome! I'm planning on utilizing some zip ties to essentially suspend the unit and isolate it from any grounding points.

- Jonathan

 

::Update::

So I pulled the rear seats, side panel and passenger rear seat to gain full access to the area like normal. Instead of using the mount to directly bolt to, I just bolted up the mount and created an insulation barrier to prevent the weird issue. Zip ties and rubber/cardboard is my permanent fix for now. Just need to fix the passenger door bottom speaker and the head unit volume **** (missing the inner plastic piece?)...and then she's up and running audio wise 100% for now.




Thoughts on this would be appreciated.

- Jonathan

 

I am rather surprise for five days since your first post non of the usual ground fault experts has chime in. So here I would stake my reputation at risk to try diagnose what seems like a ground fault. I don't have HK anything let alone the one in Mini but I do have some insight on HK system configuration. As you have not enumerate your audio configuration which including if the HU has been replaced, and likewise if any speakers have been replaced. I ask as the possibility the problem is likely a result of someone monkeyed with the system and indeed introduced a ground fault.

In many car audio the speaker wire pairs are both hot. Hot is a layman term that neither can be grounded, and I believe the standard issued Alpine made HU is the same. The HK main amplification and signal processing unit mounted in the boot interface to the same basically same HU via the HU's speaker outputs and neither wire of each pair is not grounded - so each pair is like differential pair. These are the inputs into the HK amplifier module.

Similarly the HK's amplifier output to the speakers has wire pairs that are both hot. I can see that if someone monkeyed with any of these and unwitting grounded some node(s) it MAY explain for the overnight batter drain you experienced.

The other possibility more remote, is someone unwitting defeated some isolation device like plastic washers at metal to metal or metal to PCB mounting points.

Here are just a few of my thoughts.

And BTW, the reason behind why most car audio speaker wires are all hot has to do with they tend to be bridged class AB amplifiers. Bridge amp is chosen for the power efficiency as well as max wattage given the same power supply headroom.

 

Finally got a response, I was also surprised after all the views to not have someone say something about this system as it's known to be very problematic. The always hot configuration makes sense now and the only thing the previous owner did that I can see was add an aux port in the glove box. The guy said he just put a new battery in it and the amp wasn't even secured in the back leading me to believe that he couldn't figure out how to prevent the system from drawing on the battery. Whatever, the door speaker has been replaced and the system sounds perfect now. If there are anymore issues I'm going to gut the system along with the awful stock nav. Thanks for the reply!

I think I can focus on a polish now that it's all systems go for now.



-Jonathan