Disaster strikes. Just fed my head unit with an amplified output.

theg00se · 01-04-2013, 10:42 AM

I had just finished upgrading my base system by installing a cleansweep and 6 channel amp when I stupidly mixed up the head unit feed to the left rear that should have gone to the clean-sweep with the output left rear from my amp. I turned the system on and there was a short high-pitched noise then nothing.

I have just disconnected the head unit outputs to see if there is any sign of life. I’m not sure if this is the right way to measure the outputs but with a multi-meter set to AC there is approx. 40mV from the right channel front and rear and about 20mV from the front left and nothing from the left rear. I also connect a speaker to see if the audio could be heard. The right channel could but it was vey crackly and faint. The left channel could not be heard.

Have I wrecked my head-unit or something worse. Any help greatly appreciated.

afsar · 01-04-2013, 11:51 AM

Was your car coded to HiFi or standard 6 speaker stereo? Is HiFi then speaker test will be faint music. You need to connect an amp and then speaker to test it clearly, I generally use a broken headphone which sounds loud enough on low level signal.

theg00se · 01-04-2013, 01:53 PM

Hi, the head unit is the base system standard 6 speaker not the HiFi. it does not have an amp fitted as standard. The navigation system still works obviously without the sound.
I think i must have totalled the sound and now its going to cost a fortune to fix.

ctuna · 01-04-2013, 08:46 PM

http://www.ebay.com/itm/BMW-professi...8e553c&vxp=mtr

theg00se · 01-05-2013, 09:47 AM

ctuna: thank you for the ebay info. replacement head units in the UK are a small fortune.

What could really do with is a member to spell out what my next steps should be. I worried that i could by a replacement head unit and fined that it something else thats busted.

Do you think my first step should be to remove head unit and send it off to a specialist for checking.

If i have to replace the head unit, will the car need recoding?

ctuna · 01-05-2013, 09:58 AM

Those head units come from Czechoslovakia I think . The new ones have built in usb and bluetooth phone and HD radio . The one without most bus is cheaper. Otherwise I would be looking for a repair shop.

The OEM ones on ebay are a half or less than what you would pay at a dealer but still a rip off at what you would pay for a feature laden modern deck.
To prevent this kind of thing in the future its always good to use a meter to verify your connection and check three times . The measurements you make should make sense.

theg00se · 01-05-2013, 12:06 PM

What do you mean when you say, "The one without most bus is cheaper". Not sure what the "most bus" is.

I take your point about feature laden modern decks. If it wasn't for the i drive feature i would swap it out.

As for the checking advice. Taibanl had given me some great advice regarding how to upgrade and if i had followed this to the letter i would not be in this pickle.
I will not make that mistake again.

ctuna · 01-05-2013, 12:58 PM

taibanl · 01-05-2013, 09:09 PM

So you fried something. Something can be replaced. I can't point you in the right direction for the EU but very good electronics techs can diagnose and fix issues at the circuit board level. If you found the right place, you could be out an hour's labor.

theg00se · 01-06-2013, 08:53 AM

I think i might try and find a replacement head unit and get mine head unit fixed slow time and then sell it on ebay.

I have seen a few professional head units for sale but the sellers can not tell me what the donor car setup was i.e (UK England) base system, Hifi or logic 7. The units all look the same from the front and but some are different at the rear.
I was hoping that once i get mine out and see what the back of the unit looks like, i could just get one that look identical and then get it coded to suit my needs. I have noticed that many forum members have had their base system recoded to hifi this suggest that the units must be same apart from coding.
Can anyone confirm this?

Does coding only change the attributes of the head units sound delivery or match it to the car for security reasons to stop theft?

01-04-2013, 10:42 AM	#1
theg00se Private 4 Rep 69 Posts Drives: BMW 335D Join Date: Oct 2012 Location: England iTrader: (0)	Disaster strikes. Just fed my head unit with an amplified output. I had just finished upgrading my base system by installing a cleansweep and 6 channel amp when I stupidly mixed up the head unit feed to the left rear that should have gone to the clean-sweep with the output left rear from my amp. I turned the system on and there was a short high-pitched noise then nothing. I have just disconnected the head unit outputs to see if there is any sign of life. I’m not sure if this is the right way to measure the outputs but with a multi-meter set to AC there is approx. 40mV from the right channel front and rear and about 20mV from the front left and nothing from the left rear. I also connect a speaker to see if the audio could be heard. The right channel could but it was vey crackly and faint. The left channel could not be heard. Have I wrecked my head-unit or something worse. Any help greatly appreciated.
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01-04-2013, 11:51 AM	#2
afsar Lieutenant 38 Rep 405 Posts Drives: BMW X5 xDrive40d Join Date: Jul 2011 Location: London iTrader: (2)	Was your car coded to HiFi or standard 6 speaker stereo? Is HiFi then speaker test will be faint music. You need to connect an amp and then speaker to test it clearly, I generally use a broken headphone which sounds loud enough on low level signal. __________________ 650i F12 - HUD, 6WA, SLI, Logic 7, Dynamic and Adaptive Drive, Comfort Access, Soft-close, top-view, Previous X5 40d M Sports and 535d LCI
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01-04-2013, 01:53 PM	#3
theg00se Private 4 Rep 69 Posts Drives: BMW 335D Join Date: Oct 2012 Location: England iTrader: (0)	Hi, the head unit is the base system standard 6 speaker not the HiFi. it does not have an amp fitted as standard. The navigation system still works obviously without the sound. I think i must have totalled the sound and now its going to cost a fortune to fix.
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01-04-2013, 08:46 PM	#4
ctuna Lieutenant General 1911 Rep 13,101 Posts Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca iTrader: (0)	FYI http://www.ebay.com/itm/BMW-professi...8e553c&vxp=mtr
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01-05-2013, 09:47 AM	#5
theg00se Private 4 Rep 69 Posts Drives: BMW 335D Join Date: Oct 2012 Location: England iTrader: (0)	ctuna: thank you for the ebay info. replacement head units in the UK are a small fortune. What could really do with is a member to spell out what my next steps should be. I worried that i could by a replacement head unit and fined that it something else thats busted. Do you think my first step should be to remove head unit and send it off to a specialist for checking. If i have to replace the head unit, will the car need recoding?
	Appreciate 0 Quote

01-05-2013, 09:58 AM	#6
ctuna Lieutenant General 1911 Rep 13,101 Posts Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca iTrader: (0)	Don't know about the recoding Those head units come from Czechoslovakia I think . The new ones have built in usb and bluetooth phone and HD radio . The one without most bus is cheaper. Otherwise I would be looking for a repair shop. The OEM ones on ebay are a half or less than what you would pay at a dealer but still a rip off at what you would pay for a feature laden modern deck. To prevent this kind of thing in the future its always good to use a meter to verify your connection and check three times . The measurements you make should make sense.
	Appreciate 0 Quote

01-05-2013, 12:06 PM	#7
theg00se Private 4 Rep 69 Posts Drives: BMW 335D Join Date: Oct 2012 Location: England iTrader: (0)	What do you mean when you say, "The one without most bus is cheaper". Not sure what the "most bus" is. I take your point about feature laden modern decks. If it wasn't for the i drive feature i would swap it out. As for the checking advice. Taibanl had given me some great advice regarding how to upgrade and if i had followed this to the letter i would not be in this pickle. I will not make that mistake again.
	Appreciate 0 Quote

01-05-2013, 12:58 PM	#8
ctuna Lieutenant General 1911 Rep 13,101 Posts Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca iTrader: (0)	O I forgot you had I drive You pretty much have to get it repaired then. Or did you mention it. I wouldn't have thought a I drive could come with a base system. BMW stereo types http://www.e90post.com/forums/showthread.php?t=352586 http://www.e90post.com/forums/attach...2&d=1266451970 http://www.e90post.com/forums/attach...2&d=1260829447 http://www.e90post.com/forums/showthread.php?t=343673 http://www.e90post.com/forums/showthread.php?t=138949 http://www.e90post.com/forums/attach...2&d=1260829447 http://www.e90post.com/forums/attach...1&d=1209780605 http://www.e90post.com/forums/attach...1&d=1209780865 http://www.google.com/url?sa=t&rct=j...QNFyu70IsyKRlg http://www.musicarnw.com/page-2/ http://www.e90post.com/forums/attach...4&d=1278871872 read the google link near the bottom if you want to know what the Most Bus is not all cars have it now in Europe is what I have read. Last edited by ctuna; 01-05-2013 at 09:18 PM..
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01-05-2013, 09:09 PM	#9
taibanl Brigadier General 281 Rep 4,121 Posts Drives: BMW Join Date: Sep 2010 Location: NA iTrader: (4)	So you fried something. Something can be replaced. I can't point you in the right direction for the EU but very good electronics techs can diagnose and fix issues at the circuit board level. If you found the right place, you could be out an hour's labor.
	Appreciate 0 Quote

01-06-2013, 08:53 AM	#10
theg00se Private 4 Rep 69 Posts Drives: BMW 335D Join Date: Oct 2012 Location: England iTrader: (0)	I think i might try and find a replacement head unit and get mine head unit fixed slow time and then sell it on ebay. I have seen a few professional head units for sale but the sellers can not tell me what the donor car setup was i.e (UK England) base system, Hifi or logic 7. The units all look the same from the front and but some are different at the rear. I was hoping that once i get mine out and see what the back of the unit looks like, i could just get one that look identical and then get it coded to suit my needs. I have noticed that many forum members have had their base system recoded to hifi this suggest that the units must be same apart from coding. *Can anyone confirm this?* Does coding only change the attributes of the head units sound delivery or match it to the car for security reasons to stop theft?
	Appreciate 0 Quote