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Hi.
I have recently bought a 991.1 and want to install a Mr12Volt Apple Carplay / Android auto solution.
Unfortunately my car has the TV option, so I will have to loop the fiber going to it to make Mr12Volt work.
But I can't figure out where the module is in my car.
Hi.
... my car has the TV option, so I will have to loop the fiber going to it to make Mr12Volt work.
my car has the TV module too & I bought Mr12Volt months back but wasn't sure how to install it in the presence of TV module.
Can you please elaborate how to loop the TV module & if that would mean disabling the TV?
TIA
my car has the TV module too & I bought Mr12Volt months back but wasn't sure how to install it in the presence of TV module.
Can you please elaborate how to loop the TV module & if that would mean disabling the TV?
TIA
From what I can understand we will have to disconnect the fiber going to the TV module and plug in a loop.
I have bought one like this:
This will probably disable the normal TV function.
Just to make it more clear: cars equipped with either Bose, Burmeester or TV tuner have the MOST optical waveguide transmitting the digital audio signal. Fortunately all PCM 3.1, even without any of these options, still have the MOST input /output connecting to the big quadlock terminal at the rear of the PCM unit.
The MOST bus has a "ring topology", i.e., any output sends an optical signal to the input of the next component. This component repeats the signal received, plus its own contribution at its output . This signal travels to the input of the next component, until it arrives at the PCM input , where the ring is closed.
MR 12 Volt adds its own segment to the MOST bus from PCM to their external box, in order to take advantage of the digital audio signal.
The MR12 Volt solution itself simulates being a TV tuner to the PCM 3 . Thus an existing TV tuner must be made disfunctional electrically, and in the MOST ring it must be replaced. The most simple solution is to replace it by an optical loop as posted above. Another solution would be to delete the MOST connection of the TV and re- splice the connectors to form a ring again with the remaining active components. This would avoid the (maybe academic) optical signal loss of the passive loop.
To make the tuner non-operating in an another post somebody just took out the fuse for the TV tuner . This should be fuse # 6 (5 A) of row "B" in the fuse box in the right side footwell.
Last edited by Autobahnschreck; 06-17-2024 at 06:36 AM.
To make the tuner non-operating in an another post somebody just took out the fuse for the TV tuner . This should be fuse # 6 (5 A) of row "B" in the fuse box in the right side footwell.
I tried to just remove the fuse, but then there is no sound and I can not change sources on the main unit.
I tried to just remove the fuse, but then there is no sound and I can not change sources on the main unit.
Fuse # 6 /row B /RS footwell may supply different components depending on options in your car . Generally there are no differences in the PCM 3.1 itself, with-or without TV tuner.
Options in the PCM 3.1 may be satellite radio (additional PC board in the PCM cabinet) , Bose amplifier, or Burmeester amplifier.
PCM, TV tuner and any amplifier are supplied with +12 Volt by "always hot" fuses, where the PCM has a separate one (left fusebox). The PCM and the amplifiers /TV are activated by a wake-up signal line . Depending on your individual options, the fuses involved may vary, so it would be helpful to know your configuration (and if turbo, or convertible).
No-Bose, no -Burmeester do not have MOST, except for TV (digital audio signal to PCM). Either TV, Bose, or Burmeister use MOST for transmission of digital audio signal, as does the MCU box of the Mr 12 Volt system .
The no-Bose/no-Burmeester audio signal output of PCM is 4 analogue signals, one channel for each LF,LR, RF,RR, to the "premium" ASK amplifier. ( The MOST in/out of the PCM 3 is active even with the ASK analogue-audio amplifier, fortunately).
If you lose sound, when pulling a fuse, two things may happen: Either you stop the power to the amplifier, or, if you did not bridge the component without power, but it is still integrated in the MOST-ring, this component lacking power will no more transport the MOST signal to the next one in the ring configuration .
Thus it is important to know, if you did any changes to the overall configuration when you tried to pull the fuse.
If I have the tv tuner, would it show up in the sources? I’d never heard of the 991.1 having one…
It is an option, but rare. If it is there, it will show in the source menu of the PCM.
Who would want to watch TV in a Porsche 911 ? For me, it ranks even after sipping drinks in this car.
A friend of mine (f) doing this in her 718 spilled Coke over the PDK selector unit . It is sugar, water and acid. Impossible to clean. She had to have it replaced. The selector unit, not only the Coke.
Pain in the wallet.
Last edited by Autobahnschreck; 06-19-2024 at 09:13 AM.
Fuse # 6 /row B /RS footwell may supply different components depending on options in your car . Generally there are no differences in the PCM 3.1 itself, with-or without TV tuner.
Thus it is important to know, if you did any changes to the overall configuration when you tried to pull the fuse.
Wow, you really have a lot of knowledge 🙌
My car is a base 991.1, but with almost every extra option. Including Burmester and TV option.
I did no changes except pulling the fuse. It's probably as you say: it broke the MOST signal chain.
In addition I could not change the source at the PCM. I got the option to change but it would not get out of FM radio, and no sound.
Wow, you really have a lot of knowledge 🙌
My car is a base 991.1, but with almost every extra option. Including Burmester and TV option.
I did no changes except pulling the fuse. It's probably as you say: it broke the MOST signal chain.
In addition I could not change the source at the PCM. I got the option to change but it would not get out of FM radio, and no sound.
MR 12 Volt emulates a TV tuner, so you have to eliminate all interference of the "real" TV tuner with the PCM or the MR 12 V board /MCU.
My best knowledge is: the original TV tuner i) is controlled by the CAN bus; ii) if operational, transmits a digital audio signal into the MOST bus; iii) if operational, transmits a video signal to the PCM video input.
The traffic of the TV tuner on the CAN bus may be deleted either by pulling the appropriate fuse of the TV tuner supply (should be #6, row B, RH fusebox), or by disconnecting the connector at theTV tuner (removal of driver's seat required). Hopefully, if you disconnect the connector the TV tuner does not incorporate the termination resistor for the CAN bus ( 120 Ohms between CAN High and CAN Low).
The digital audio signal is transported on the MOST bus (ring topology). Its (orange) optical waveguide cable (avoid to kink) runs from the PCM quadlock connector to the right, through the passenger footwell to the Burmester amp (under passenger seat) , returns back to the PCM quadlock connector, from there to the left , passing the steering column, down to the left doorsill , under the driver's seat , connecting to the TV tuner, and back to the PCM. You have to replace the original waveguide connections: PCM to TV tuner, TV tuner to PCM by the connection PCM to MR 12 Volt MCU , back to PCM.
As far as I know, the PCM quadlock has 2 paired slots for MOST, one for connecting to Burmester /Bose amp, one for TV tuner. Thus in the original configuration there should be 4 orange waveguide cables entering/leaving the quadlock connector of the PCM ( if you look from the back side to the PCM, it is the left side/below of the quadlock) . The connectors are asymmetric, so mistaking in-/ for outputs should not be not possible.
For the video signal of the TV i believe there is a yellow coaxial connector at the (view from back) right side of the PCM. The video cable should be left disconnected to avoid interference with the MR 12 Volt video.
Hope all this is true and helps. Good luck !
Ok, so now it's mounted and all good.
The TV tuner was under the drivers seat as @Autobahnschreck instructed.
It is the one closest to the middle of the car. It has a combi socket with wires and fibre cables combined, so it has to be split up. Easy job, just one little clip and the fibre socket is out.
At this point I would optimally have an adapter like the one in the Mr12Volt kit to make the socket fit, but I didn't. I made it work for now by carefully aligning the fiber socket in the loop and secure with a ziptie.
Wires and fibre plug Split up Installed and arranged Working fine
06-16-2024, 05:33 AM
991.1 TV tuner module - where is it?
