Da habe ich frueher was gefunden:
Groeten uit NL.
Sjef.
Q: I want to put a CD player in my Saloon, but it's positive earth (ground). Can I convert
it?
A: Yes, and you'll need to make only a few changes:
Turn the battery around, or preferrably, find one with the poles reversed (limits the
possibility of shorting on the back of the open bonnet).
Reverse the wires on the ignition coil.
Inspect your fuel pump for a capacitor (common on later Mk 2/240/340/S-Type). If
there is no capacitor, go on to the next step. The capacitor in the fuel pump is a one
lead axial type. The lead is the negative pole. The positive pole is the housing, which is
earthed by the attachment clip. There is no simple way to 'reverse' it. Replace the
capacitor with a 50uF electrolytic capacitor of at least 20Volts with about the same
physical dimensions. Solder the positive pole to where the old lead was attached.
Solder the negative pole to the attachement clip ot other suitable earth. If you feel
more ambitious, the XK-Lovers have a description of how to transistorize your
original pump to save contact wear.
Run a wire from the positive post of the battery and briefly "zap" the field terminal of
the generator (reverses the residual field).
Reverse the wires on the ammeter (hard to get to on a Mk 1).
For Mk 2 and later cars, the clock in the revcounter should be disconnected.
Otherwise it gets fried. No easy way to convert it. This will probably not be a problem
in most cases as the clock in most cars is already broken.
Start it up and go for a drive.
There is no need to fiddle with the wires to the starter, fan motors, etc. They seem to sort
things out on their own. There is some indication that the washer bottle mechanism in the
Mk 2 and later Saloons is polarity sensitive. - Frank Benschop
