Hi,
To be honest, I did not order the 8-pin DIN connectors from Digi-Key. I am in the UK, and I can get them locally. But I just looked in the Digi-Key catalog and found these...
8-Pos. In-Line Plug p/n 275-1005-ND $0.74
8-Pos. In-Line Jack p/n 275-1011-ND $0.91
From the picture on the page (page 262 in their current edition), I take it that in this context "jack" equals "socket". I cannot tell whetther these are the offset type or not (as refered to in my write up), but I would assume that they are not.
You can probably also get these or very similar parts from other electronics supplier (try
www.mouser.com or if you are in the US, maybe try RadioShack).
If you have navigation, you also need a 13-pin DIN plug. These are harder to find. In the UK I got mine from Maplin Electronics (
www.maplin.co.uk).
To answer isolation question....
Before adding the isolator, I had the other two cables connected directly together. Everything works like this, and you can use it like this for testing. You will get some digital noise from the unit itself caused by the current flowing to ground, and the ground diffences between the Phatbox and the head unit, and you will have alternator noise. If yours is a petrol engine, their may also be ignition noise. I have the D5 diesel, and so I had noise from the fuel injectors.
In tracking down the problem, I tried various power and earthing arrangements. But you need to take care. I did blow the fuse in the panel in the trunk which feeds the navigation unit. And, if you get things wrong you could do damage to the head unit or the Phatbox.
(For those who are interested in the theory: Here's a technical question for when interviewing electronics engineers - When is zero volts not zero volts? Answer - any time that a system is actually turned on and doing something. Variations in current in the power and ground leads - say from 0.500 amps to 0.550 amps, caused by disc drives, processors and memories - induce changing voltage drops across the resistance and inductance presented by a conductor. It doesn't matter if it's 10 feet of wire or 6 inches or some pins in a connector. There will be some effect, and in an audio system it is likely to make its presence known.)
There is a little more history behind this on the Swedespeed forums....
http://forums.swedespeed.com/zerothread?id=47744One golden rule here. Pull the fuse feeding the navigation and Phatbox before making or breaking any cable connections, and ensure that ignition and the head unit are completely off. If you want to be really thorough you can even diconnect the battery, but that should not normally be necessary for work like this. That is, unless you don't already have the fuse in place and you need to do wiring connected to the live side of the fuse. Then it is imperative for the safety or yourself and your car that you disconnect the battery - normally by disconnecting the
negative terminal.
Hope this helps you.
Les.
