Head Unit sound cuts out after a few seconds of playing

[shy7g]

Hi all
I've got an after market head unit that is around 5yrs old, most recently the sound from the unit cuts out, the stereo is still on and all functions seem to be working other than the fact the sound has stopped.
Has anyone expected this problem or can direct me to wether this problem can be repaired?
Cheers
Rich

[henrym3]

Bit more info would be helpful, model, year, DSP, nav, type of head unit. I know it’s silly but my after market HU has no sound if battery is not in tip top condition but just has to be manually turned up once the engine is started. Check connections in the back of HU and in boot.

[shy7g]

Although she’s on a 2002 plate, I purchased the head unit, bus lead etc etc around 2012-ish, and I believe it’s an aftermarket EBay special .
When you “power on” the head unit is tuned in okay to the stations and sound is heard for about 5 to 10 seconds before it cut out all sound. If I turn the unit off and then back on again it does the same thing every time, the station(s) stay tuned in, sound cuts out every time???
When I can get 5-mins I’ll pull the head unit and check the connections, but as it only cost around £400 I suppose I’m lucky it lasted this long.
She just covered 95k and flew through the MOT again with just advisories on the two back tyres, which I was aware about anyway.
So I’ll have to talk nice to my financial manager about maybe getting an early crimbo prezzy lol......

[wpoll]

Sounds like you have a car with the factory DSP amp, which needs a data signal from the head unit to stay powereed up. I guess this WAS working , so look into how the head unit WAS messaging the DSP amp to remain active. Assuming you do actually have a DSP amp...

[shy7g]

God even more to look into, having just read the post by newbie onedaymyfriend "Possible electrical issues with the e53 4.6is" I've now found out what the "dot" next to my tripometer means,, yes the anti tamper dot.
Not totally sure when this little bugger appeared could have been after the control module under steering wheel had to be replaced with a used one and reprogrammed, but again to be honest not totally sure??
And also as the car isn't used that often and the battery had run itself totally flat last month I wonder if it's because of that the electrical issues with the stereo HU and anti tamper dot have occured?.??? Any suggestions???
These machines can be so bloody temperamental at times

[shy7g]

Sounds like you have a car with the factory DSP amp, which needs a data signal from the head unit to stay powered up. I guess this WAS working , so look into how the head unit WAS messaging the DSP amp to remain active. Assuming you do actually have a DSP amp...

Okay no idea of how to " look into how the head unit WAS messaging the DSP amp to remain active" here's a photo of the rear of the aftermarket HU, Any Help??

IMG_0129.JPG (65.26 KiB) Viewed 7929 times

So how would you find out if the DSP Amp is faulty?

[henrym3]

If you have any problems with these vehicles you are wasting your time trying to trace them unless you’re working with a tip top battery. First sign my battery is getting weak is I loose my pre set stations on radio. The vehicle starts fine, no sluggishness, absolutely no indication other than the stations have dropped out. Now I’m doing shorter journeys I stick it on the trickle charger overnight once a week. Remember just because the vehicle starts and runs ok doesn’t mean your battery is in tip top condition.

[henrym3]

Check the fuse on the DSP, also check that there is no water in the bottom of the area the DSP sits in. Remove and check the DSP plug leads for corrosion. If you have DSP fitted you must have the long harness lead from the HU to the boot so check the connections on that as well. Even if it looks good disconnect and check the pins for corrosion.

[shy7g]

Check the fuse on the DSP, also check that there is no water in the bottom of the area the DSP sits in. Remove and check the DSP plug leads for corrosion. If you have DSP fitted you must have the long harness lead from the HU to the boot so check the connections on that as well. Even if it looks good disconnect and check the pins for corrosion.

Thanks henrym3 for the advice, much appreciated.
Is it best to disconnect the battery before checking all connections?
Is there any type of spray cleaner on the market that does a good job?
A new harness which came with the aftermarket unit was run from the boot to the front previously and having an LPG tank in the well just makes it abit more challenging
Cheers
Rich

[wpoll]

shy7g, you still haven't confirmed if you have a DSP amp. 'Cause that make a difference...

The fact that you get sound for a few seconds remove the wiring from the list of possible issues. What you have are the classic symptoms of the DSP amp not being sent a data signal over the car's data bus to state "awake". There is no "wire" for this - it requires a data packet (called a telegram) over the car's computer data bus to wake up the DSP amp.

On the android head unit, you possibly have an app called iBus. This app "talks" to the DSP amp and tells it to stay awake. The iBus app is normally set to start up when the head-unit starts and it need to to this in order for the DSP amp to work. Your recent battery issues may have "reset" your head-unit's set up and now the ibis app isn't launching.

If I'm right, you have DSP and the iBus app, try launching the iBus app on the head-unit and see if the sounds works correctly.

There are other ways to get the DSP amp working with Android head-units, mostly involving keeping the old MID or Nav system plugged in (in either the glove box or the boot/trunk) and given the age of your system, it's possible you have one of these arrangements. Dunno.. but the current method of choice with DSP and Android is the iBus app.

[shy7g]

Hi all, at last I've has 5-mins to play on the car, taken the following two units out of the car.
- BMW PROFESSIONAL BM54 AMPLIFIER BECKER 65.12-6 919 078 AND - ALPINE STEREO RADIO AMP AMPLIFIER 65.12-8 379 376

BMW PROFESSIONAL BM54 AMPLIFIER BECKER 65.12-6 919 078.jpg (75.15 KiB) Viewed 7800 times

ALPINE STEREO RADIO AMP AMPLIFIER 65.12-8 379 376.jpg (60.56 KiB) Viewed 7800 times

So can someone explain to me what these two units do and which one would more than likely be causing the problem?
Cheers
Rich

[wpoll]

The Becker BM54 unit is the radio receiver and first-stage amplifier module and the black Alpine unit is the second-stage DSP amp.

As I've mentioned, the sound will not work unless there is some arrangement to activate the DSP amp (the Alpine unit). If this was working for five years then quit, then something changed that arrangement, whatever it was.

Most likely, there was a software function on the head unit that activated the DSP amp - commonly an app called iBus but there may be other (earlier) apps. My guess you did a software update or changed the software in the head unit and now the DSP activation is working.

But that's just a guess, as I don't have enough information to be sure.

[Greydog]

Just read this post an I am confused, the original post says there is an "aftermarket" headunit fitted. Yet there is still a BM54 connected and a DSP unit though the DSP picture shows what looks like water stains on the label which may be the source of the issue.
With my 4.4 when I fitted the Dynavin headunit as Henry has said a long extension lead connected the quadloc connector at the BM54 to the Dynavin head unit basically making most of the stuff in the boot redundant so I took it out and sold it.

So interested in knowing what the head unit is, if it worked with the BM54 and DSP did it work with the CD and Nav or were they built into the head unit?

[shy7g]

Okay - update
Today's been bitter sweet.
FIRST OF ALL WPOLL - 9/10 I now think/ know that there must be a communication error between the Aftermarket HU and the Alpine Amp unit.
Only 9/10 as I also discovered that one of the cables on the aftermarket harness to HU plug had broken away, Although the cable is Pink I don't know what that particular position of the cable does?? Any ideas anyone??

IMG_0132.JPG (35.13 KiB) Viewed 7771 times

so now have to see if there's a tool on the market to remove the very small female connectors out of the plug - Any suggestions please give me a heads-up, thanks

So regards to whether or not either/or both amps are working?
I checked and cleaned both the BM54 and the DSP Alpine amp units terminals and had a look inside both just to see if something looked out of place and got rid of any dust etc etc.... So I decided to reinstall the OEM GPS unit, the OEM Head Unit and reconnected the original harness and hey presto there was sound and constant at that. The only prob. with this OEM HU / GPS is just the age of the technology and having to dig around in the cupboard for my old cassettes that I know my kids will love LOL!! and that the GPS disc is 2000 to 2002, Can this be upgraded with an uptodate disc? AND more importantly the only problem I can see with the OEM HU straight away is that there's a red fan shaped light permanently ON - WHY ???????

OEM HEAD UNIT.jpg (54.05 KiB) Viewed 7771 times

A BIG THANKS TO ALL WHO HAVE PARTICIPATED IN WORKING THOUGH IS PROBLEM WITH ME

I'll post some info and photo's of the aftermarket HU when I get 5-mins.. and will power up the HU on the bench and have a good look through all the menus

Cheers
Rich

[wpoll]

Great fault finding so far, Rich - nearly there.

It looks like the missing (broken) pink wire is one of the data lines from the HU to the car. This would explain why communication signals to the DSP have been lost. I'll bet you also lost the steering wheel controls (volume etc.) but didn't notice that....

Steering Wheel Control - Transmit Data (SWC-TXD) and Steering Wheel Control - Receive Data (SWC-RXD) are probably more general data connections than just the steering wheel controls but as I don't know the brand and model of your aftermarket head unit, I'm not 100% sure.

I would suggest you resolve the broken wire, plug it all back up and you should be sorted. As for how to repair the broken wire, once again, without knowing the exact model of head unit I can only guess as to the connector/pin size but a generic pin extractor tool should sort it.

Like this... https://www.amazon.co.uk/Terminal-Remov ... B0734HHRQB

Good luck!