On Wed, 23 Dec 2015 18:26:09 -0800, mike wrote:


The ammeter read backwards and the gas gauge pegged negatively
but nothing was harmed

What a bunch of youngsters. ;-)
Back in 1963, my dad had a TV repair shop.
He did some work for a car repair shop.
One day he fixed the blown output transistor on a car radio.
This was when car radios still had tubes, but they had switched
to one transistor in the audio output.
Car guy bought it back...It's broke.
Fixed it again.
Car guy brought it back...IT'S BROKE!!!
Fixed it again.
This time Dad and I went over to the shop and
measured the battery. Was charged backwards.

I remember those old tube car radios with a power transistor output. I
know that anything with transistors wont tolerate reversed power. It
just burns up the transistor(s). Modern electronics that operate on
batteries (Cell type, like AA AAA C D), generally have a diode or more
to prevent burning up the device because it's too easy to put in
batteries backwards.

If my tractor has a transistorized radio, or electronic ignition module,
it/they would be fried now. But I dont have any of that.....