The diode converts AC from the alternator to DC for battery charging etc.
It basically acts as an electrical "check valve", only allowing the positive part of the AC sin wave through and blocking the negative part. The result is a pulsating DC current.

IF you no longer have the diode, this is the cheap solution.

www.radioshack.com/product/index.jsp?productId=2062591

This post was edited by bill_kapaun on Mon, Aug 4, 14 at 23:55

Thanks Bill. ..I'll be at radio shack this morning.

Thanks Bill. ..I'll be at radio shack this morning.

Thinking about this a bit more RE blowing the fuse.
My first thought was no, but then I considered-
Some tractors have a direct connection between the diode and the positive post of the battery via the small red wire connected to the + solenoid terminal. Others have this switched out via the key switch.

I don't have a schematic, but if it's the first style, you would have 12V feeding directly back through the stator coil from the battery and no diode to block it when the engine wasn't running.

This may blow the fuse, but even worse, it may have "fried" the stator.
IF it didn't, trying to charge the battery with AC tends to kill batteries.

This post was edited by bill_kapaun on Tue, Aug 5, 14 at 11:22

I'll finally get a chance to install the diode tonight - the consequence of a fried stator would mean 'no battery charging'?
I'll let you know...
thanks again