Yesterday, I was installing the 6V battery in my 9N as I have done for many years. Upon snugging up the braided positive(GROUND) cable, I started hearing a sizzling sound. Before I could loosen and yank the grounded positive cable off the battery, smoke filled the barn and I could not even see the battery to do so. I finally was able to disconnect and remove the battery. From what I could see, the old "yellow" colored wiring connecting to the ammeter had worn insulation from age and shorted out to the chassis from my disturbing during the battery installation.I have plenty of 12GA wiring and plan to rewire the tractor. I believe the ammeter got fried as it is series connected and is all fogged up now. Is this just a "standard issue" 30 amp ammeter and where is a good parts source? I also plan to replace the badly corroded ballast resistor. What is the value of the ballast resistor for my 6V 9N? I could kick myself for not paying better attention to the condition of this old wiring..