This was something I found once in a parts drawer at a TV Repair Shop in Altamonte Springs, Florida back in the early early seventies. A friend of mine worked there. (His prior job was designing Monsanto's 'Circle Vision' projection screen exhibit at Walt Disney World! His other love, aside from repairing tube-type TVs was being the projectionist at the Prairie Lake Drive In, right off Hwy 17-92! Can you dig that? Einstein with a Soldering Gun. His name was Jim . . . .)
Where was I?
Ok. In that parts drawer lay several very small, tightly wound coils of what looked like 22g wire. They were tinned. Jim called them "pig-tails". Their use? To solder together two pieces of wire, of course!
I cannot tell you the mountain of frustration I climb whenever I have to get into tight spaces with a soldering gun, and when you mess with point to point wiring in some of these older rigs, you need a hefty soldering pencil. Why is it that the one thing that has to be pulled is always a multi-point solder in a tight corner that either requires a complete dis-assembly or a very dangerous de-soldering? You can't get a braid in there, and forget the solder sucker. I never liked the sucker anyway. The braid isn't bad . . . but you need a fairly open area. Both are unwieldy, IMHO.
TV repair guys were in tight spots all the time. These little pig-tails saved them a lot of time (and mess). "Pig-Tails" are not generally available these days, so I began making my own. I thought I might share how I do these little items, and if you are new to this sort of thing, I'll also include a few shots of an actual repair I made on my last project, the AC-3 power supply rebuild for a Drake TR-3.
First, I picked up a spool of 22 gauge tinned bus wire. Next, I went to Hobby Lobby and got a pair of very small double-round needle nose snipes, the kind that florists use to make tight little loops in . . . whatever it is they make tight little loops with . . .
Holding the wire at the very, very tip of one jaw of the snipe, I twist the wire in such a way as to make a look about the holding "jaw", and then slide that loop up one layer for the next loop. I always make the loops at the very tip of the snipe jaws to make the smallest possible aperture. If I want a larger diametre hole, then I will wind the looks further down the snipe jaw.
See how the resulting 'pig tail' progresses up as I wind each loop, or "pi"? You can wind them as long as you wish, and as wide as you wish. See how the snipe jaws are conical? The lower you wind, the wider the diametre. I usually wind mine such that the two wires that I am joining together might have a little overlap room. When the loop is finished, simply cut it off. You can also leave a little stub of wire available to hold the pig-tale in place if you are in a tight enough spot. This can be handy because you have to slide the pigtail over one wire, and guide the other wire through the pig-tail from the other side. In a tight spot, it might be handy to have a length of pig-tail wire available for a "third hand" jig to hold, leaving both your hands free. I rarely have to do this, but just an idea.
So, how do we use a pig-tail? Well, let's take a look: the above repair was the result of a mis-wired filter cap. See the limited length of wire I had to work with? That multi-point solder would have been a disaster to desolder. Better to keep the original solders . . . if they are good solders . . . alone. So, in this case, I will pig-tail that length of red insulated wire to that center ground wire from the potted cap you seed there. (It's not really potted, I made that cap. It's a re-built paper cap, I use hot-glue to set the bottom and hold the exiting wires in place. They do not get hot.) BTW, this is a filter cap for the AC-3 negative bias supply. I had to flip the polarity, dumb me.
There you go. The pig-tail you saw on the snipes is being used here. Pretty obvious what is happening here. The two wires meet and slightly overlap. All that is needed is a touch of solder. Remember, the wire used for the pig-tail is already pre-tinned, so solder flows readily, affecting a very solid connection with a minimum of heat exposure to the surrounding components. In this case, I will do what Drake always seemed to do: use very little insulation if buses carrying high voltages are far enough to not be in danger of touching another wire or ground. Flip over a TR-3 or TR-4 sometime, and look at the sparsity if insulation used! But then, heck, I remember a time when house wiring was bare, too. That's why you wanna watch your head when crawling around the attic of a house that was built much before 1940! Bare wire and stand-off insulators!
Solder applied. A good solid connect. The only thing I might add to this narrative is that if you are so inclined, dear reader, you might locate some heat shrink tubing if you have a fear of cross connections with another, nearby bus. You can find small diametre heat shrink tubing at "Just Radios". I usually find my replacement caps here, too. Read their hints and tips page regarding cap replacement!
Just in case you were curious where we were doing this solder connection, let's step back and get a wider panorama. There it is, upside down AC-3, my "Third Hand" jug, and my 30-watt soldering pencil that dates back to the days of Lafayette Radio Electronics. Yup, it's about forty years old. Still kicking.
Ok, gang, that's it! My little "Tip Of the Day". Nothing new, but it may be new to some of you.
As I progress on the TR-3 Restoration, I will post here. There will also be some totally unassociated Letterpress stuff coming up, too. I have four new dies coming in!
Stay tuned! de wd4nka.