Some years ago I was a volunteer fireman in a small Upstate NY town. On one of our pumpers, a '58 Mack, one of the two (redundancy, y'know) battery strings (two huge 6V batteries in series) was self-discharging if the rig sat idle in the barn for more than two or three days. Determined to find out why, I went up to the firehouse one night with my multimeter. I disconnected the negative terminal and hooked up the meter. One of our younger guys was looking over my shoulder and asked whether there was any reason why I had disconnected the negitive terminal instead of the positive. Wow! Here was my chance to show off how smart I was. I explained that when working on a vehicle battery, one should always first disconnect the negative terminal, because that way, in case the wrench made contact with the vehicle's frame, there would not be a big short circuit current! I then proceeded to demonstrate this for him by bridging my wrench from the negative battery terminal to some nearby metal. It was at that moment that I discovered that Mack trucks of that vintage had positive ground!! Ever see a box end wrench instantly get converted to an open end??
73 Ray K2HYD _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
