Switched and unswitched +12v sources for DVB-T.

[HPsauce]

I'm looking at adding a DVB-T tuner to my RNS-D. I've had a rummage round both here and wider online and not found a clear answer on where to pick up power from.

I already have the tuner and aerial, I played with it a fair bit on my PF S8, but there I already had the early analog tuner (and wiring) to interface through to the RNS-C. There is no tuner in this car, just the CD player.

Are switched and unswitched +12V available in the loom to the RNS-D, I've looked at the labels but can't interpret them? I'm thinking of how to provide power to an A/V interface which as far as I can see will need both.

Also, what power (and in which core) is supplied to the CD changer; I'm wondering if I can tap into that for the tuner and/or interface box. All I have behind the boot panel is the CD changer and parking sensor unit.

Ideally I'd like to use the tuner with ignition off, so a similar mechanism to whatever turned on the OEM TV tuner would be ideal, unless that's done by a signal rather than supplying power.
However, I didn't solve that problem on the PF car, so I could only run TV there with the ignition on, so maybe it's beyond my skill set?

[notorious]

I'd suggest to get ELSA and study wiring diagrams.

RNS-D power connector should look like this, but I can't guarantee:



I think you can get power from CD changer harness. CD changer is controlled by RNS-D, so it knows when to power it down when key is out.
However, this can be problematic from CD changer side as connector is 'sealed'.
I'd also look at DVB tuner power requirements before stealing power from other devices.

CD changer pinout can look like this, but please check ELSA for your car:

[HPsauce]

Thanks very much, that's EXACTLY what I needed to know.

I'll get my trusty multimeter out to check as well. My labelling is rather different though, which is why I was

To be specific, the 8-connector block at the top, which is of most interest, has:
Top line: Earth, "Sun", S.Kont, TEL MUTE
Bottom: UB+, SAFE, K.BUS, GALA

The little aerial (what is that?) on the picture above is SAFE on my RNS-D which I believe is a permanent +12v to stop you re-entering the security code.
And what is K.BUS - anyone know?

By the way, the individual wires going into the CD unit are fairly accessible with the cable cover/clamp removed.
Colour codes on the CD Changer fly-lead seem different, but the plug is also fairly easy to open so identifying them by position should be easy. The plug is numbered and correctly "mirrors" that above.

EDIT: Found some info online which suggests your picture is of a Symphony radio label which is "slightly" different and doesn't require a separate "SAFE" wire.
RNS-D is like the attached picture:

[HPsauce]

So, thanks to Notorious I'm pretty confident on finding permanent and switched 12V power, both in the boot and by the RNS.

But does anyone know the answer to this, or will I just have to fit a bypass switch, rather than somehow using the inbuilt on-off-timeout facility in the RNS?

Originally Posted by HPsauce

Ideally I'd like to use the tuner with ignition off, so a similar mechanism to whatever turned on the OEM TV tuner would be ideal, unless that's done by a signal rather than supplying power.
However, I didn't solve that problem on the PF car, so I could only run TV there with the ignition on, so maybe it's beyond my skill set?

[notorious]

K.BUS is diagnostics wire that goes to OBD socket. When you connect VCDS it talks to all your devices via that wire. On newer cars a normal CAN bus is used for that.

Start looking at ignition lock diagram on ELSA. One wire will be the wire that keeps +12v with ingnition off until key is removed. But is this what you need? You can switch on RNS-D without key in ignition and listen CDs until it switches itself off by timeout. There must be wire that supplies +12 to CD changer from RNS-D for the period when RND-D actually needs CD changer. For cars of that era this should be done by wire. Same power logic should apply to BOSE amplifier if you have it. Look at the back of your RNS-D. First "Symphony" picture I showed has the "Remote Amp SW. On" callout. Is that what you need?

On "CD" block of wires on your RNS-S there's also "switched" +12v pin. Just like on the line-out block. Take your tester and check.

Check power requirements of stock CD changer or BOSE amp. See power requirements of your DBV tuner. If it needs a lot of power use the pins I recommended to drive a relay that will deliver +12 volts directly from Terminal 30 (constant +12v). The reason why you'll need a relay is because I assume that CD changer and BOSE take power for their operation from a separate constant +12v feed and they only use the RNS-D pin we are discussing to switch themselves on or off based on presence of +12v signal on that wire via internal relay.

You DVB tuner may or may not have two power pins. One for information to switch on and one for actual power as it was not manufactured by Audi.

If you take all the power from the pin we are discussing you may burn RNS-D.

Hope it makes sense.

[HPsauce]

Originally Posted by notorious

There must be wire that supplies +12 to CD changer from RNS-D for the period when RND-D actually needs CD changer. For cars of that era this should be done by wire.

Yes, that's what I thought, but wasn't sure. It expect it will be essentially unchanged from when the A8 first appeared for the whole D2 life.

On "CD" block of wires on your RNS-S there's also "switched" +12v pin. Just like on the line-out block. Take your tester and check.

Yes, I was going to do that. It did occur to me that might be controlled by the RNS rather than the ignition, which is what I ideally want.

[notorious]

I think I edited my reply with relay logic while you was replying

[HPsauce]

Yes, I was thinking about using a relay for that exact reason, but that will depend what my testing reveals including measuring current draw.

There is a UB+ output on the CD block of the RNS and I know my XcarLink, (which is ONLY connected via that socket) gets power when the RNS is turned on independently, so it seems very likely that output is switched by the RNS not ignition.

[HPsauce]

I've checked the socket on the CD fly lead and it's somewhat different to the image posted.
There may be some confusion due to "mirroring" but I'm going by the actual (tiny) pin numbers moulded onto the socket.
Mine has:
1 red, 2 black, 3 white, 4 black. These are clearly the L/R channels as the blacks become the shields to the other 2.
5 green, 6 blue (unused), 7 grey, 8 unused. Only 6 and 8 are used in the image below, for 12v and ground.
9 black, 10 yellow (thicker!), 11 orange, 12 unused. All 4 are used in the image.
13 brown.

Time to do more research/testing I think.
There are 8 connectors for the CD on the RNS but 9 here (combining the 2 signal earths and ignoring 6 blue), maybe that's just down to a separate power ground?

Originally Posted by notorious

CD changer pinout can look like this, but please check ELSA for your car:

[notorious]

ELSA is the only reliable source of wiring information for particular car.