Most of the StationPro assembly entails soldering
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1. WS8ZR s Tips for Wiring Circuit Board Jumpers Most of the StationPro assembly entails soldering components onto circuit boards but there is a small amount of point to point wiring mostly installing short jumpers from front panel connectors to pads on the adjacent printed circuit board A few builders have struggled with this part of the assembly so for these folks here are a few hints I ve learned over the years The first step is to diagnose the problem and I ll use the StationPro microphone connectors as an example since they have the most wires in the smallest space The two photos below show the wiring of a builder who struggled several hours trying to solder jumpers to the StationPro s microphone pads As you inspect these photos take note the following problems 1 The wires are roughly twice as long as necessary Excessive wire length makes it impossible to route the wire bundle neatly and to keep track of individual leads Overly long wires tend to get caught on components when they re stuffed into an enclosure and the flexing puts stress on solder joints Furthermore it s very hard to avoid touching adjacent wires with your soldering iron when there s a snarl of wires around every connection If you look carefully you can see melted insulation on some of the wires Rule No 1 Jumpers should be no longer than necessary to reach neatly from point A to point B 2 The insulation on some wires is stripped too far b2. ack from the solder connection look at the blue wire on the right side of the left photo Obviously uninsulated wires in close proximity are prone to short circuits In this case the tinned lead was too thick to fit into the hole in the circuit board One reason it wouldn t fit is that the wire s strands weren t twisted tightly before tinning and too much solder was used to tin the strands But the biggest reason is that the builder used hookup wire that was too big for the job No 20 AWG in this case instead of the called for No 22 AWG One can always use smaller wire within reason without problems for short jumpers but it s impossible to do a good job if the wire is too thick Note also how the wires seem to crowd the pads with very little clearance between pads Rule No 2 Use the correct size hookup wire for the job Tinned leads should always fit easily into mating circuit board holes Go smaller if necessary but never bigger Rule No 3 Tin but don t over tin stranded hookup wire before connecting it and be sure you first twist tightly the leads The purpose of tinning is two fold 1 it keeps tiny loose strands from causing short circuits or mushing out the strands as you slip them into the hole 2 it helps wet the solder bond between the strands and the sides of the circuit board pad The final problem isn t visible from the photos but is a frequent source of trouble and that is wires that extend too far into th
3. e circuit board hole and out the other side In this example if wires extend below the circuit board too far it s not possible to get wire cutters into the narrow space between the circuit board and the front panel This situation invites short circuits between adjacent wires Rule No 4 Don t overstrip insulated wires A rule of thumb is to strip wires that connect to solder lugs 1 4 in and wires that connect to circuit board pads 1 8 Most printed circuit boards are 1 16 in thick so a wire stripped 1 8 in will only extend through the bottom of the board 1 16 in which won t cause any problems Now let s take a look at the same connectors wired according to the above rules MIC CONF IG MIC1 MICe CONFIG Note how easy it is to follow which connector wire goes to which pad and how the clutter has been eliminated by merely shortening the wires Also note that by using proper gauge wire there is now ample space between pads thus minimizing the possibility of short circuits Because these wires were stripped only to 1 8 in the insulation covers each wire right to the solder blob and the wire extends only a safe 1 16 in on the underside of the board Also note that sleeving was placed over each wire in order to cover the microphone pins This is done partly for cosmetic reasons but also because installing the sleeving on the wire requires one to tug slightly on the wire thus revealing quickly any poorly soldered wire
4. red I carefully dressed the wire It is good wiring practice to have each wire come up vertically from its pad for a short distance and then veer over gracefully without sharp bends toward its destination I used different colored wires for each pin because I happened to have many colors on hand However as you can see from the photo that s a minor benefit If the wires are short and neatly dressed there shouldn t be any confusion if you use the same color wire On long runs just use an ohmmeter It s MUCH more important that you use the right kind of hookup wire than multiple colors even if you have only one color Without good hookup wire you are doomed to failure Now a word about soldering irons When working with small wires No 22AWG or smaller it s essential to use a small tipped soldering iron with a sharp point on the tip For the connections in the above photo I used an Aoyue model 968 soldering station bought on eBay The tip was 1 2 in long and tapered from 1 8 in gradually down to a fine point A nice feature of this soldering station is that it has a little tube connected to a vacuum pump to draw solder smoke away from the joint so you can see what you re doing and won t cough all night But there are many other acceptable soldering irons I also use a Weller EC2001 with an EC200C soldering pencil which has a 3 8 in long tip that is 0 1 in at the thickest point and tapers gradually to a fine point Whatever
5. s on the mic connector Here are another few tricks I used to simplify the wiring First I used teflon insulated hookup wire which one can frequently find at hamfests QTH com or eBay Don t pay retail because it is very expensive Teflon insulation doesn t melt so there s never a problem with accidentally melting insulation On the other hand teflon insulation is tough which makes it a bit harder to strip Never try to strip insulation teflon or otherwise by gripping it with wire cutters and pulling I use an Exacto knife single edge razor blade or box cutters with a fresh blade to cut carefully the insulation around the wire and then pull off the end by gripping it with wire cutters It takes a few seconds longer to strip wire this way but you end up with a nice clean strip Also clamp the wire with needle nose pliers while you re pulling off the insulation so you don t pull loose the other end I know not everybody will be able to use teflon insulated wire For common plastic insulated hookup wire you ll find that the insulation will melt easily and sometimes shrink and pull back from the heated end In that case you should tin the wire first and then clip it to 1 8 after tinning In wiring the above connectors I started at the bottom row of pads and worked systematically toward the top row That way it was easy to get my soldering iron onto the pads without having other wires get in the way After each wire was solde
6. soldering pencil you use it HAS to have a fine point No wedge tips allowed And variable temperature soldering irons are a big plus I normally set the temperature at about 730 degrees F but crank it up higher when soldering to ground planes since they really soak up the heat You want to make sure solder flows onto the ground plane and doesn t just ball up on the lead And let s not forget solder For the photo I used ordinary tin lead solder resin flux naturally of diameter 031 1 32 Don t use anything thicker because a you won t be able to sneak it down next to the pad and b it will draw off too much heat from your soldering pencil And now TIl finish with a few obvious but important tips 1 Esthetics count If your connection doesn t look good it isn t good Pay attention to every single wire and every single solder joint Inspect every joint with a magnifying glass dress every wire as you go along and if everything doesn t look right then strip it out and do it over Believe me you ll save time in the long run It took me about one hour to wire up these two microphone connectors 2 Don t start wiring until you have the right tools You re headed down the path toward total frustration if you don t have a good soldering pencil right sized solder a sharp knife or box cutter a magnifying glass a bright light small high quality needle nosed pliers and flush cut wire cutters and sharp pointed
7. tweezers 3 Don t rush Let me repeat that Don t rush Think of the tortoise and the hare You ll get to the finish line faster and happier if you take your time work only when you re rested and stop as soon as you feel your edge slipping And finally keep in mind that none of this is rocket science Wiring neatly and carefully doesn t take talent a high IQ or even experience Okay maybe a little experience But basically all it takes is a systematic step by step approach a modicum of patience and the ability to recognize when something looks good and when it doesn t Your goal isn t just to complete a StationPro that works when you re done although that obviously is an important goal You also want to build a StationPro you can be proud of End of sermon
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