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FM reception and diversity amp location.

Posted: Thu Jan 01, 2015 1:13 am
by AW8
FM reception not that good at times.

I would like to sort this but not confident in success.

My E53 has16:9 screen comms pack (nav,TV, phone) but absent of DSP.

Amp/tuner is BM54.

Signal loss could be down to.....

BM54

Radio signal suppressors (below side windows)

Diversity amp in rear tailgate ( I found it so can confirm its prescence - it is not wet/damp) and I believe another possibly located forward of the trunk/boot......according to realooem.

Break to coax,window connectors or elements etc.

I have tried randomly unplugging the BM54 plus diversity box under top of tailgate plus the interference filters ( which I had prior thought were signal amps) .

Spoke to Rich at Barkers Motor Works who advised checking earth but reckons it is not possible to pinpoint diagnose the FM reception issue other than swapping out components by trial  and error to narrow down the cause. If components ruled out it is a case of painstaking wiring integrity checks.

I have read a variety of posts and online info but yet to see anything convincing which is specific to my car. Lots of random BMW related
posts out there - few if any of real substance and specific to my set up.

Have spoken to a guru who repairs BM54 units but even he is unfamiliar with location of diversity amps or aware how to fix them.

Anyone fixed this issue ?

Anyone know a specialist who actually knows enough and can narrow down the issue re signal loss ?

If I can't get someone to sort this I may have to resort to trying to find a brave volunteer with a donor car so I can swap out various bits with a view to possibly  narrowing this down.

I am sure I am not alone and suspect many don't publicly admit to the issue as they are not confident in rectifying and fear post trawling come time to sell on.

Fortunately I can get most very local and national stations most of the time but a diagnostic at Indy indicated an issue with FM reception.

.

Re: FM reception and diversity amp location.

Posted: Sat Nov 28, 2015 6:02 pm
by mattyp
did you sort this problem?

Re: FM reception and diversity amp location.

Posted: Sun Nov 29, 2015 11:55 am
by AW8
The BM54 amp was exchanged around 4 years ago as I had loss of sound to speakers. The connections have been checked to diversity amplifiers and I have also tried exchanging the fm diversity amplifier for one I sourced on eBay. I have also Checked for visible damage to window element.

Oh and the answer is NO - Reception works on all BBC and also local stations but sometimes it's just a bit poor. Not sure if something defective or just another E53 characteristic !

Ideally I need to park up next to another owners car, compare reception of same stations &/or maybe swap over modules etc.

Re: FM reception and diversity amp location.

Posted: Sun Nov 29, 2015 4:50 pm
by mattyp
I can only get one local radio station with mine if I tune it manually. and that is just poor, crackles etc. I have bought another module (the one which is in the boot quarter panel and I am going to fit this and see if it helps

Re: FM reception and diversity amp location.

Posted: Sun Nov 29, 2015 5:59 pm
by AW8
Good luck, will keep eye for updates.

Re: FM reception and diversity amp location.

Posted: Sun Dec 13, 2015 1:20 pm
by mattyp
I had to remove the battery today, when I reconnected it I had rds working on the radio. I can still only get the local radio station but now it displays the radio name??

Re: FM reception and diversity amp location.

Posted: Wed Dec 16, 2015 8:55 pm
by mattyp
Problem fixed , I changed the amp in the tailgate and now it works