I've searched on this and found a number of possible solutions, none of which have worked. The situation is as follows:

2002 TD6 Vogue with DSP etc.

No sound from anything and screen is defaulting to the one driven by the TV module so it looks like this. I don't have the sat-nav plugged in, that comes later-

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Click image to enlarge

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Click image to enlarge

Hi LB,
You are correct: the screen is dumb. I do find it difficult to believe that more than one unit in the infotainment system has died simultaneously: w/o the nav-computer connected you should have all other functions with the display format you show. Unless you had serious water ingress which has now dried and actually left multiple components damaged, I'd still look to the i-Bus first. You may have one bad unit that is causing issues on the bus system. Start by disconnecting everything except the TV module from the system, then re-connect one component after another testing for function each time.

I would not rip everything out - with a MKIV nav computer and SW update, the system is actually quite good IMO. About the only drawback is the missing touch screen - and then really only when you are entering addresses. And none of the aftermarket units have the level of integration you do with OEM bits.
 
RRC 2Dr, RRC 4Dr,
P38, and 2 L322s
(wife thinks I'm nuts - prob right, too)

You could try checking the 10A fuse on the top of the BM54, below the large connector plug.
After that I would guess corrosion of one or more plugs on the DSP or in the DSP itself.
Worth also "wiggling" the cables to the connector plugs on the top of the DSP whilst the radio is switched on.

Well I've ripped the whole lot out of mine, head unit, BM54 DSP amp TV Sat Nav DVD and fitted the Android head unit and I still get the OBC data come up on the dash display when I press the end of the steering stalk, In which case I would imagine your problem has nothing to do with the units listed above.... Who knows what it could be then.... Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-

I'll try the one by one option as recommended and see what I get. The lack of OBC does seem to be a different issue but as I said before it's not clear where this info comes from or where it's stored. I have accessed the so-called "secret" menu on the display and things like mpg etc. are being stored but not being displayed.

Not sure about the OBC, but it's the sat Nav that drives the screen graphics.

I take it the system has always been like that whilst you've had the car ?

I'd check the part number of the sat nav unit.

That said, the older units will try and drive the screen with a 4:3 aspect ration instead of 16:9.......

Can you get a firmware update cd from somewhere ?

I take it you have the mk3 sat nav with just a black front, without DVD on it ?

Can you see anywhere a firmware version. Could be like 3/01 or something ? 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport

The nav computer makes the graphics come out in a nice LR color scheme - but there are default graphics if the nav dies or is disconnected. LB had the nav disconnected according to his 1st post.

The OBC info is stored outside of the infotainment system - most likely the cluster but I am not certain (never looked into it ). If the Android units can access that, then it is a step up from the older imitation BMW head units that people were selling. I still don't like them - and the curved faceplate does not cut it. But this is simply my opinion.

But that is not what I meant with integration: it is not only the OBC data or little things like being able to set the clock (without disconnecting and reconnecting the battery at exactly 12:00 as I read somewhere ), it is things like being able to scroll your contacts in the info display in the cluster, voice commands activated by the steering wheel buttons, or in the case of a diesel, being able to set the park-heat timer (park heat needs to be activated with an appropriate diagnostic tool, of course ).

You are driving a GBP70k car. It is not worth saving a few hundred quid. As above, tho, this is just my opinion. Everyone needs to choose what makes them happy  
RRC 2Dr, RRC 4Dr,
P38, and 2 L322s
(wife thinks I'm nuts - prob right, too)

Haven't had a chance to do anything for a while other than take everything out but for the TV ready to put in one unit at a time. Had a spare 10 minutes this morning so put it all back in in stages and lo and behold I had sound!! The radio had stations and the tape worked. The CD cartridge is missing so no way to check that. Had a quick play with settings etc. and all fine. Didn't plug the satnav in as I'm sure that needs a software re-flash.

Felt very pleased with myself.

Went back out a couple of hours later and guess what, no sound!! Back to as it was before with no radio stations etc.

I'm now thinking it might be a dodgy aerial because the DSP and radio pre-amp etc. must be working. More investigation to do. I've got the software and hardware now to check the I-bus so will give that a go and see what it tells me.

Try disconnecting the battery -ve terminal, reconnect, steering full lock to lock and see if your sound comes back on.

No result disconnecting battery etc. Disconnected everything again and reconnected radio and DSP. Have sound again!! Leaving it until the morning to see if it stays working. Sounds good when it works.

If it goes off again which it probably will instead of disconnecting everything try disconnecting the largest of the three plugs on the DSP and reconnect it and see what happens.
I suspect you have a bit of corrosion on one of the plugs or sockets due to past water ingress and the DSP is the prime culprit for this. If you remove the plug look for any signs of green verdigris on the plug connections or the pins in the socket.
If you find any it needs cleaned off.... very carefully.

A word of caution, if you do find you need to clean any of the connections on this socket it's a good idea to remove Fuse 49 on the glove box fuseboard first as the Red/Green connection is permanently live from the battery.

Well still have sound after a few days. I sprayed all the connectors with cleaner, dried them off and put it all back together and so far so good. Now it's stable I'll start connecting the other units back in and hopefully the faulty one will show up. Sending the satnav off for re-flashing and hopefully that will sort that out.

mine has not got that box and everything sound related works fine
nice when you find the offending item

The ff had the TCM which is the telephone control module and that voice recognition unit available as options.

In later BMW cars, they were combined To form the ULF units, which can be retrofitted to offer integrated bluetooth, as you prob know......

 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport