Some time later I realized that my auxiliary ground wire from the diode board was still connected to the battery.

YIKES! Luckily I am carefull when removing that cover so nothing happened.
Now I disconnect all grounds from the battery.
You're right.ME 109 wrote:Good tip Doug, and also a good point to disconnect at the battery due to the likelihood of eventually damaging the thread at the other end of the ground wire in the transmission casing.