DSP Amp swap no power

[Gray Matter]

Swapped 98 740il DSP Amp into 96 750il but doesn't power up. Tuner still lights up. Any help much appreciated

[Mayorchuck]

Does the 750 have the same audio components as the donor car, i.e. DSP, Nav.? Were you having a no sound issue? Do you also have the head unit/tape deck to swap?

[Gray Matter]

98 740 and 96 750 seem to have identical components so by using the donor cars tuner, (no nav,) (cd in the trunk) it could solve a possible code issue. I wonder if the central computer has a lock-out code. Dealer was decidely vaque before$$$ per hour.

Reason I took out old amp because of what I think was a blown channel on the rear door

[Qsilver7]

Can you clarify some of your vernacular? I'm not sure what you mean by "tuner".

The e38 uses a multiple component audio system that includes a MID (mutli-informational display) and a separate in-dash cassette/radio unit...and separate amp (which can be DSP or non DSP). Then there is the navigation set-up where the radio tuner is a separate component located in the trunk along with the amp...and the Nav screen becomes the controller (like the MID in earlier built e38s).

When you say tuner...I'm not sure if you are referring to the cass/radio unit or the MID. The MID performs no calculations etc...and is just a simple input device that receives & displays data/info from the systems that are connected to it....and allows you to control those multiple systems (clock/audio/phone/OBC) from one single location.

The audio system in the e38 is not "coded" like the previous generation of BMW anti-theft radios where if electrical power was removed...the radio requires a specific 5 digit code that needs to be entered before the radio will work again.

[Gray Matter]

Thanks Qsilver7. My 96 750 has no nav. The dsp amp from the 98 740 looks identical to the one I am replacing due to a suspected blown channel. The radio tuner in my 750 does light up but the unit above it (MID I think) does not. Every thing worked in its respective vehicle except the blown channel to the rear door. I need to find out if perhaps the mid? is tied into the car's ECU or the like. cheers