Analogue to Digital TV in 2002 S8

[HPsauce]

Originally Posted by HPsauce

I've already arranged switched power slaved off the CD player feed from the RNS-D.

Coming back to the power supply options I have slaved into the CD player feed at both ends, both in the boot and at the RNS, but......
There are two power feeds in the lead, one is a constant +12V even with ignition AND RNS off. The other one comes on with the RNS, even if ignition is OFF.
That all makes sense, you need constant power to the CD changer to eject cartridges and you can run the RNS (all options) without the ignition on.

But which circuit is for which exact purpose and rated/fused to what level?

My expectation would be that the constant +12V is the main power feed for the CD changer, with a decent capacity, and that the other one is more of a "on signal".
If that is the case I'll probably use a relay to supply power to my DVB-T tuner when I install it, though I have tested it directly using the RNS-switched supply.

I'll start by having a delve into my Bentley manual later to see if that helps. Meanwhile does anyone have any views or information on the capability of each of those 12v supplies?

[HPsauce]

Originally Posted by HPsauce

I'll start by having a delve into my Bentley manual

Not a great deal of help as it's US-based so doesn't seem to cover RNS and for some odd reasons the CD connectors are a mirror of my documentation and cable colours are different; took a bit of logic to decode.

But assuming the CD connection from a Symphony is the same as an RNS-D we do indeed get the two 12v supplies I have identified, maybe someone can decipher these:

12v constant labelled "BATT" at the changer and "Dauer-plus" at the radio.
12v switched labelled "ACC" at the changer and "gesch.Plus" at the radio.

[IT]

I would avoid hacking around with the CD changer cable. The CD changer plugs exclusively into the back of the head unit, so any power you draw off that, you are drawing through the RNS which won't have been designed for it, although admittedly you would likely get away with a single relay....

If I were looking for ignition feed in that area on a non-bose car I'll be looking at pin B22 (Black with blue stripe) on the PDC controller, which should be under the CD changer in the boot. That's a direct ignition switch.

For the main power, I'd be taking it from the fuse holder above the battery. Best case, create a new fused loop, worst case, tap into the audio loom supply which runs out of there anyway. I'm sure the handbook will probably document which it is....

[HPsauce]

Thanks Ian, good thinking as ever.

My logic is that, being mechanical, the CD changer will draw a fair bit of power, far more than a simple bit of electronics (TV tuner and CVBS-RGB converter).
So the RNS should be designed to feed that through and up the cable to the CD changer.
The XCarlink unit already sits in that loop and "flip-flops" between itself and the CD changer anyway though I don't know which option it uses for its own power.

My best guess is that the RNS has a pretty "straight through" feed on the constant 12v circuit so that should be safe for small loads.
And I could actually just do without the CD changer and disconnect it; I rarely use it.

[IT]

As I was hurtling through some countryside this morning in my D2 I had a thought about aspect ratios:

The RNS-D is old school 4:3

Isn't most digital stuff 16:9 ? And being so old, the RNS-D has no concept of letterboxing the screen image, so aren't you going to end up with a horizontally squashed picture at the end of all this ?

Wouldn't the reversing camera suffer the same issue, or have you thought one step ahead and managed to source a camera that outputs a mirrored 4:3 image ?

[HPsauce]

Originally Posted by IT

have you thought one step ahead and managed to source a camera that outputs a mirrored 4:3 image ?

Of course I have, and with guide lines on it - didn't I post some sample images earlier?

In the multiuser thread about installing the camera, see here for todays RNS view: http://forum.a8parts.co.uk/showthrea...393#post126393

And the TV tuner is configurable to a selection of aspect ratios, letterboxes, stretches, anamorphic etc. etc. so no problem there.
It also has HDMI, S-video and CVBS outputs, though is missing the one you REALLY need for an RNS, RGB. That's what the separate converter box does.

[HPsauce]

Originally Posted by HPsauce

So the RNS should be designed to feed that through and up the cable to the CD changer.
The XCarlink unit already sits in that loop and "flip-flops" between itself and the CD changer anyway though I don't know which option it uses for its own power.

My best guess is that the RNS has a pretty "straight through" feed on the constant 12v circuit so that should be safe for small loads.

I've just had a look at the XCarlink wiring - took it out of the car as it's rather bulky behind the RNS and I'm going to reconfigure it to make it easier to refit.
Anyway, it has a 5A fuse in it's wiring, in that constant 12v circuit.
So while I'm at it I'll make sure any 12v take-off I use is protected by that fuse. Should be OK then.

[IT]

Originally Posted by HPsauce

though is missing the one you REALLY need for an RNS, RGB. That's what the separate converter box does.

That's half of it.

The other half is the converter box should be injecting its presence onto canbus so that the RNS-D actually knows that there is a possible RGB input to switch to - Prior to you installing that box, you presumably couldn't even select TV as it knew you didn't have one connected.....

For this reason, simply hooking up RGB to back doesn't work. Many have tried and failed.....

[HPsauce]

Originally Posted by HPsauce

a 5A fuse in it's wiring, in that constant 12v circuit.
So while I'm at it I'll make sure any 12v take-off I use is protected by that fuse.

Done and refitted, though a bit of "readjustment" is still required behind the RNS as something is stopping it going back that last 5mm.

I now have a 12v supply, protected a 5A fuse, energised via a relay when the RNS is on (irrespective of ignition). I've moved the CVBS/RGB converter box to that and the RNS does indeed "see" a TV input all the time now, though when selected it currently says "No Signal" unless I'm in reverse.

I'm just about ready now to start testing the TV tuner in the car.

[HPsauce]

First test, that's it for today.
Aerial not yet supplied with power and we're in a valley in a rubbish reception area, but it still got Channel 4!