Sound / Radio not working after multiple MKIV Nav Computer Units

[R3VN R3D]

Hi all,

If someone could please point me in the right direction, I would greatly appreciate it.

I have an 01 740iL.

When I bought the Car, the Stock MKIII was bad so my Radio would shut off after a few minutes and the Screen was blank.
But I could always restart the Radio and the Sound would come back for another few minutes.

I bought an MKIV on Ebay and it worked great at first.
Then things started to deteriorate.
The Screen started to flicker and go white and come back, then the Radio would cut out, then come back.
Finally, the Radio / Audio stopped completely, but I still can see everything on my Screen, although it still flickers.

So, I threw money at the problem and bought another MKIV on Ebay. Stupid move.
This 'New' one is doing the exact same thing. No Sound and I can see everything on Screen.

It is almost like the Speakers all went out or another component in the System went bad.

Not sure what to do at this point.

Everytime I try and do a search with my Symptoms, I read about people having the first problem I had where the MKIII Nav Computer was bad.
I've been there and am passed that with a new set of Symptoms.

Thanks all.

[DennisCooper]

Hi,

Screen flickering could be the TFT panel itself on it's way out, usually the 'backlight' but it means a replacement panel is needed and then having to open up the monitor to swap it out which is quite a tedious job. If you take your time on it, you'll need to memorise the disassembly and re-assembly procedure, I'd suggest giving a couple hours to do this and longer if you make the mistake(s), which you will and have to undo the last few bits of the procedure and re-do correctly. The Mk4 GPS computer can 'drive' the monitor without the need for a video module, but internally that might also be on it's way out/faulty, you could test by swapping in a known working Mk4 unit.

As your audio is now non functioning, the BM53/4 amplifier module is likely faulty which is common, so to test, it's a swap with a known working module.

I know many owners wish to keep the oem audio setups, which is fine, it's just now those modules are getting on for between 11-18 years or so old, they're failing more often and of course, the fixes are relatively expensive. Each module also has multiple points of failure so sods law means that if the TFT panel in the monitor is bad, you'll change it and then the ribbon cables/volume PCB/motorised down/up gears etc aspects will fail/go faulty and/or in the amplifier module, you'll fix the dry solder joints issue (the main symptom) and then one of the IC's on the PCB will blow and you'll lose all audio again etc.

In short, keeping the oem setup working long term will cost you the most longer term as well, on top of that, you can have the amplifier upgraded for better specs like adding a Bluetooth reciever to it and having RCA phono leads adapted in and an Aux in done etc, all of which cost more money.

I'd suggest removing the oem setup and storing away in case you wish to sell the car, or selling off if you intend to make the car a long term keeper, and spending the money you would have on multiple fixes and repairs towards a high quality head unit and install with excellent brand upgraded amplifiers and speakers/subwoofer(s). The head unit will have all the latest technology built in too. If you do later decide to sell the car, you can put back in (working) oem modules and you'd still have your high quality audio gear to either install in your next car or sell on to recoup some money if needed at that point etc.

If you do wish to keep the oem modules regardless, then do look at Carphonics here in the UK who can do the repairs and the optional extra upgrades - you might as well do them all in one go due to the shipping costs! I know the owner of the company very well and 100% can vouch for him, so do not feel as though due to international shipping there's any extra risk as there isn't at all - http://www.carphonics.co.uk/

I know there's USA repairers, but I'm not sure if they do the 'upgrades' ;

http://www.hitechserv.com/

Cheers, Dennis!

[Onizukachan]

Dennis means well, but he's in the U.K. That's a long way to ship something you can buy off eBay.
Also you may have the bm24 since 01, all those upgrades don't really apply.

you just need another radio/tuner module, or to look inside yours and see if there is an obvious fault.
US variants rarely fail, but that is what happens.
You can use a bm54 but you need a BMW adapter to go from round pin to flat pin.

In the future remember, display and audio are two separate things coming from two separate places.

[R3VN R3D]

Still wrestling with my Amp.

Looking to replace Amp with and Aftermarket Unit. Looking at the JBL GTR-7535 with Bluetooth.

I am ok with having to replace the 14 Speakers as well.

I am just wondering, before I pull the Trigger, will this mess anything else up in my Systems like DSP, Fade-able Speakers, my MKIV Nav Unit, etc...

Finally, should I just replace the Amp with another Factory Unit and then just do a Bluetooth Integration with a Mediabridge or a Grom System?

Thanks.

[DennisCooper]

Hi,

If you wish to keep the oem monitor/screen, the DSP, Mk4 GPS unit, you *must* retain the oem amplifier as it's integral to the setup and you cannot just 'bypass' it. If you buy the JBL bluetooth enabled amplifier, there's no Audio output via bluetooth from the OEM setup so no point in getting a BT enabled amplifier. To get 'input' into any excellent quality amplifier, you'd need the oem BM21/53 unit that works properly and fully as that will give a speaker signal out.

Onizukachan also means well, we're trying to help you! As per my initial response, the oem audio modules in 1996-2006 E39/E38/E46/E53 and others are failing more often now, repairs and fixes are relatively expensive too and there's multiple points of failure for each module.

It's up to you if you wish to continue spending to keep the oem setup fully working.

In about a month or so, the Avin brand has a E38 specific all in one replacement type unit for the E38 comining out at a base price of $699 USD. https://avinusa.com/avant-3-for-bmw-...on-system.html. They're promising OBC support and DSP support. Do keep in mind these units are made over in China and using low grade components/electronics. If they'd have been made using better, higher quality ones, they'd have ensured their marketing was emblazoned with information about it.

The solution I'd suggest is to go with a high quality aftermarket head unit so that you get a modern featured high reliability and much better sounding head unit. The issue is that you don't retain full OEM looks and there's no full OBC or DSP support. From what you've said, it sounds like you wouldn't want this route though.

Cheers, Dennis!

[R3VN R3D]

Hi,

If you wish to keep the oem monitor/screen, the DSP, Mk4 GPS unit, you *must* retain the oem amplifier as it's integral to the setup and you cannot just 'bypass' it. If you buy the JBL bluetooth enabled amplifier, there's no Audio output via bluetooth from the OEM setup so no point in getting a BT enabled amplifier. To get 'input' into any excellent quality amplifier, you'd need the oem BM21/53 unit that works properly and fully as that will give a speaker signal out.

The issue is that you don't retain full OEM looks and there's no full OBC or DSP support.

Cheers, Dennis!

Thanks for the Reply again.

I don't mind losing DSP, but losing full OBC Support worries me.

If I replace another Stock Amp, I really want to integrate Bluetooth somehow.

Thanks again.

[DennisCooper]

Hi,

If you do stick with the OEM modules, then keep in mind OEM bluetooth only does mobile phone hands free calls, it doesn't have the capability for Audio streaming. Keep in mind also, new handsets/mobile phones come out all the time, and currently, it's iPhones which have the best chance of being fully compatible with the old BMW BT modules. Android is more hit and miss. Another owner with the same phone as you will have BT mobile phone hands free working on their E39/E38/E46/E53 and you'll have the same phone and the same BT module version and it'll not work as good/properly. This is due to variances in the software and compatibility with different Bluetooth Stacks etc. You can then do the same 'loop' as you are already having to do, try different oem BT modules till you find one that works. Then of course, when you change your phone again either/or due to loss/theft/upgrades etc, you might find the new phone doesn't work properly !

On top of all that, then the next batch of top end handsets will come with Bluetooth Version 5. They do say it's backwards compatible with older BT versions, but I suspect, although could be wrong, that some phones will not work at all with the old BMW BT modules, or there may be more 'hit and miss' with Android handsets and perhaps even iphones.

The new Avin above promises OBC support, so once it's out, and people begin to install them, lets see if there's any problems/issues or indeed, if it works very well etc. If it is a reliable and quality setup, then I'd say go for that unit as BT will already be on board and no extra faffing about installing looms and modules like you'd have to do with the OEM route.

'DSP' is talked about alot on the BMW forums and it was great, in 1995! by the end of the 90's it had fallen out of fashion for consumer electronics - church, stadium, jazz club etc effects just didn't excite consumers as much anymore. Unfortunately, here we are almost 2 decades later and BMW owners still wish to keep 'DSP' and also the mediocre when new DSP speakers in their cars. After all this time, they're even more mediocre ! but those with DSP seem to want to keep them for fear of taking their door card off and replacing with much better sounding high quality 2 way components instead. The Avin now seems to be the 2nd aftermarket head unit to 'integrate' with the OEM DSP amp - I wonder if this time it'll also keep the DSP functionality too?...

'OBC' is also another feature set that's wanted when changing from the OEM setup to an aftermarket one. This is understandable of course. There's many many E39's which didn't come with the MID setup and only had 5 or so parameters that could be scrolled across and displays in the instrument cluster. I'm one of those so equipped E39's and for me, I can't miss what I didn't have! I don't really need consumption 1 and 2, av speed 1 &2 and other OBC parameters, so my aftermarket unit choice is wider. Those who *must* retain the OBC, can either retain the OEM setup, get the MID display setup and working or, buy the Avin 3 once it's out and if it's OBC implementation is any good.

Cheers, Dennis!

[R3VN R3D]

Thanks again Dennis.

I think for now I am starting to think I will just replace the Amp and add a Bluetooth Integration with a Mediabridge or a Grom System.

Now I don't know if the Symptoms I have mean I have to replace the Amp or the Radio Module without trying to replace each with a working Unit.

[R3VN R3D]

A bit of an update:

I would like to say, Tomas at BavTek is awesome!

Super nice guy, helpful, good Prices, quick Shipping and he went above and beyond to help me.

It turns out, both my C43 Tuner and DSP Amp were the Culprits.

Like my Original Posts reads, after I installed the new MK4, I got a new Set of Symptoms resulting in No Sound.

Tomas told me that since I couldn't switch my Input Modes, but I could enter my DSP Menu, that it most likely was my C43 Tuner.

But if I was able to switch my Input Modes, but my DSP Menu was 'greyed out' and not selectable, that it was most likely my DSP Amp.

In My Case, I had both.

I bought a new (to me) C43 Tuner and Amp from BavTek for super reasonable Prices.

I then tried a combination of their Tuner and my Amp with no Sound and then my Tuner and their Amp, still no Sound.

Then I tried both the new Amp and Tuner together and now I have Sound.

So, in the end, I am back to fully operational with a couple residual quirks.

I do get a random flicker on the Display Screen that I can only assume will get worse over time.
Also, now not all the Options in the DSP Menu are selectable like 'Set' and 'Room/Echo'.

So I'd say this is resolved.

Thanks for the help.