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Loud pop then no sound from the speakers

Posted: Wed Oct 06, 2021 11:37 pm
by mrpogosian
Driving back from a holiday last week, heard a very loud pop and hiss from the speakers (seemed to come more from front left), then no sound at all. the normal chimes etc. are all coming from the instrument cluster.
I've tried the following:
Reset SYNC (next and power button)
disconnect battery
checked for DTCs - nothing relevant
ran all self tests on modules - all tested goo

All my research has been pointing to a faulty/damaged ACM, however the self test showed no issues. Another suggestion was that a speaker may have somehow shorted out. I've checked the resistance across the coils on the fronts, will check the rears another day.

Has anyone else experienced anything similar or could offer any assistance?

Cheers,

Re: Loud pop then no sound from the speakers

Posted: Sat Oct 09, 2021 11:38 pm
by mrpogosian
An update, hopefully this helps someone.

I opened up the acm as, pulled the pcb out and gave it a flex. Plugged the bare pcb back into the car and everything functioned correctly.

Seems like the pcb in the acm may be suffering from cold joints or something.

Re: Loud pop then no sound from the speakers

Posted: Sun Oct 10, 2021 8:59 am
by saeb
Only on the odd program.

Usually worst case disconnect battery for 10 minutes, a few minutes won't be enough to drain the capacitors in the unit.

Re: Loud pop then no sound from the speakers

Posted: Mon Oct 11, 2021 7:47 pm
by mrpogosian
Thanks for the tip Stewart,

I had previously tried disconnecting the battery for a couple of hours with no success, hence deeper dive.

Annoyingly it's presenting similar early symptoms again (small pops with no audio for a few seconds after).

Are you aware of anything that can be done to prevent this?

Re: Loud pop then no sound from the speakers

Posted: Mon Oct 11, 2021 7:55 pm
by saeb
Always do programming, especially of ACM with any audio turned off.

Apart for that I have heard of maybe 3 that have failed, just because.. So worst case see if you can find a cheap used one at a wreckers, making sure it is an XLT or Wildtrak. anything else wi not support DAB.

Being there are so many Rangers that have been through the wrecking yards it makes no sense to even look or try to repair them at this stage.

Ask for the CD player and not the ACM to avoid any wtf looks.

Re: Loud pop then no sound from the speakers

Posted: Mon Oct 11, 2021 9:39 pm
by mrpogosian
Thanks Stewart,

I'll keep an eye on it and try the wreckers if all else fails.

Appreciate the help.