Date: Sun, 15 Dec 1996 12:05:11 -0800 From: Mike West Subject: RK Electronics, pumping your spades Road Kill electronics and spade connectors. . . . . Woke up this morning and my computer wouldn't work. Whacked it a few times. . . . it still wouldn't budge. "What's different from last nite?" say I. "It's cold", says three or four appendages. Brain goes on a tangent how that may impede the flow of electrons. "Get real" sayeth the Forebrain to the Lizard section. Spocking it out. . . . there's power lights at the power strip, so I know it's getting that far. I get down and jiggle all the connectors etc. Still no joy. Throw a small hissy fit. . . . . wipe the foam and drool from my face I get down and go at it scientifically. I have one of the "Mega Universe" power strips with $30k insured surge protectors. . even my phone goes thru it. Being such a "bad ol' thing", it has more connections than I have equipment. I pulled the computer plug out and moved it to another plug-in. Everything works fine. So what happened and how come I'm wearing gloves while I type? It's cold in here and my fingers get numb hanging out there in the wind of my blinding typing speed. I could warm it up but I have to go change bottles on the propane etc. By that time I'd be warmed up and not need it. . . . . It promotes hair growth and long life. Unfortunately it doesn't seem to do much for the head portion. Putting aside the personal discomforts and rationalizations, What happened is that the damn plug corroded. AC voltage is not noted for it but it do happen, a lot of moisture helps. We have had some moisture. Also hot and then cold helps. The moisture and other stuff is pulled in by the temp. changes and so on. Those of you who normally carry a firearm know about this. Ammo that will keep for years in a box will go to hell in your gun in just a few months from being carried out in the heat and then back into an air-conditioned office. Or vice versa. Sucks moisture right in there. So I said AC (alternating current) is not noted for this. AC is reversing the current 60 times per second and doesn't really have a "flow" in one direction for plating out a connection. DC (direct current) does. It always flows in one direction and there- fore has what's referred to as "electrolytic action". Put a little moisture in the equation and you're plating part "A" with the metal from part"B". Stick some soot in the equation and you have even more problems. Carbon has 6 valences or little hands to grab stuff with, that's why it's such bitchin' stuff to make things out of. Like your cereal. Hahhhh! :-) But it also makes it easy for it to get in and wreck your electrical connection. Take a piece of metal and scrape a shiny spot on it. Right before your eyes, it will dull. Thats called "tarnish". It's a nice name for "corrosion". Oxidation etc etc. So we start out with a new connector, say a spade connector, and the damn thing is already "tarnished". A spade connector is a flat tongue of metal that another flat tongue with curled over edges like fingers that slips over and hold the flat piece, making an electrical contact. Shape is like a "spade", hence the name. You may call them "removable" but the real name is "temporary". As opposed to permanent. The same is true of any plug connector etc. Now we started with this nice new tarnished connection that already has some "resistance" to it. Just a little but enough to make some heat when current is applied. Not that we needed the heat, there is already enough in the engine compartment. Or inside the car. When all cools off, after you go to bed and the beasts are at large... The little connection sucks in some moisture and soot. The guy carrying the pistol under his arm knows to switch ammo every few months. When was the last time you switched spade connectors? OK we don't do that, don't even go down there any more. Still, if it's a plug-in, it needs cleaned every few months or it is creating resistance in your electrical system. To clean a spade or plug connector, the simpest way is to "pump" it. Pull it apart and back together a few times. "Pump it" This wears a clean new path thru any corrosion, restoring good contact. If it's a ground screwed to metal, the corrosion is generally under the terminal next to the metal part. We don't think much of "grounds", did you know the electrons actually flow from the "negative" to the "positive"? Pull the screw and clean under there, then re-tighten. Dab it with some vaseline on top to keep away moisture etc. That does not mean grease all your connectors, the grease is a non- conductor like corrosion. Permanent connections: splices etc. these should be soldered or they will just go bad in a while. Use the butt connector, say, and crimp it in but then whip out your little torch and solder the thing in. All the electricians tape in the world won't keep out moisture or prevent electolytic action. You want a good seal around that splice, get a piece of shrink sleeving, pull it over the connection after you've soldered, then put a good sealant inside the ends of the sleeve, then shrink it down over the connection. Do not use RTV silicone as an insulator on bare wire. The ascorbic acid it uses to cure with, eats the hell out of copper. And if you do have reason to go down to that part of town. . . . Swap out your ammo and pump your connectors. It could save the life of someone very close to you. :-) west