Slot Car Corner - Making a Controller Adapter

Slot Car Corner

Making a Controller Adapter - Jack to Alligator Clips

Introduction

When fabricating controller hookup panels, I receive quite a few requests to include a jack so racers with Ninco or Scalextric style controller can plug their controller directly into the panel. Including a panel mounted jack is certainly a nice way to do this; however, what if you have a controller with a plug adapter and plan to race at a commercial track or with a club or buddy whose track has the more traditional 3 post setup for alligator clips? Not to worry - here's a how-to article which shows you how to fabricate an adapter which works with BOTH Scalextric (mini style) or Ninco (1/4") controller jacks.

Note: Click on any of the thumbnails to see a larger image (Use Browser "Back" Button to Return)

Step-by-Step Instructions

The picture to the right shows the basic components needed to fabricate the controller adapter. To assemble the adapter, you'll need a soldering iron (with stand and cleaning sponge), rosin core solder, rosin flux, a wire cutter/stripper and some small clamps. Always wear safety glasses and follow all manufacturer's instructions and safety guidelines when using tools.

Note: The components shown are available in kit form in the Online Store. If you prefer, pre-assembled adapters are also available for purchase.

The first step is to remove the "barrel" or "frame" of the 1/4" jack from the outer housing. Most barrels are threaded; however, some are snapped or pressed into the housing.

Once removed, examine the frame carefully. There are 3 connectors - 2 smaller "tabs" (silver and gold) and a longer, curved connector. These are the connectors the 3 wires will be soldered to.

So now the question is "Which wire goes to which connector?" The accompanying picture shows a 1/4" stereo jack and the corresponding controller wire colors for each of the 3 "bands". Now examine the inside of the jack frame (unfortunately there is no way for me to photograph this). If you're using the jack included in my kit, you will see 2 contacts - one is gold, the other is silver. These correspond to the small gold and silver (solder) tabs on the outside of the jack frame where the wires will be soldered to. Now take a closer look at the contacts inside the jack frame. Notice the gold contact is further down the barrel than the silver contact. Now imagine inserting your controller plug into the jack. The tip of the jack will contact the gold contact. Referring again to the accompanying picture, we see the "tip" of the jack corresponds to the "red" controller wire. Therefore, the red wire in the kit will be connected to the solder tab for the gold contact. The middle band of the plug or "ring" will contact the silver contact inside the jack frame. The picture shows the middle band corresponds to the black controller wire. Therefore, the black wire in the kit will be connected to the solder tab for the silver contact. The only wire left is the white wire - it will be connected to the long curved contact on the jack frame. To summarize:

the gold jack contact and solder tab corresponds to "red" controller wire,
the silver jack contact and solder tab corresponds to "black" controller wire, and
the long curved silver jack contact/solder tab corresponds to the "white" controller wire.

Note: If you are using a different jack, the same basic steps apply. If you are using an open frame jack instead of the closed frame jack shown in this article, you can simply insert your controller plug to see which contact on the jack is making contact with each of the bands on the plug.

Next strip about 3/16" of sheathing from the end of all 3 wires as shown.

Now use your soldering iron to "tin" the end of each wire. Apply some liquid flux to the end of each wire. Make sure your soldering iron tip is clean and apply a small drop of solder to the tip. Touch the tip to the bare wire - the solder should "flow" from the soldering iron tip to the wire as shown.

Soldering the wires to the jack frame will be MUCH easier if you have both hands free. A small clamp like the one shown will hold the jack frame securely while you position and solder each wire.

Before soldering the wires to the jack frame, give some thought to the order the wires should be soldered in. If you are using the jack in my kit, it will be MUCH easier to solder the white wire to the long, curved connector first and then solder the remaining 2 wires to the small tabs. If you soldered the wires to the small tabs first, it would be difficult to position and solder the white wire to the long, curved connector. Before soldering each wire, apply some liquid flux to each connector and the tinned end of the wire.

Solder the white wire to the long, curved connector as shown. You can then reposition the jack frame in the clamp to facilitate soldering the next wire.

Next apply some liquid flux and solder the red wire to the corresponding solder tab (the "gold" tab if you are using the jack frame in my kit). Make sure the tip of your soldering iron is touching the solder tab - you want the soldering iron to heat up the solder tab which in turn will cause the solder from the tinned wire end to "flow" over the tab. Once the solder begins to flow, wait a second or two and remove the soldering iron tip. Wait a few more seconds to let the solder cool and setup before repositioning the jack frame in the clamp to solder the remaining wire.

Again, apply some liquid flux and solder the black wire to the corresponding solder tab (the "silver" tab if you are using the jack frame in my kit).

Use a pair of wire cutters to trim the other ends of the 3 wires to the same length as shown.

Now insert the 3 wires through the jack frame cover as shown. Make sure to insert the wires in the proper direction and use care when working the wires through the strain relief.

Tip: A small drop of dishwashing soap on the wire sheathing will make it easier to insert the wires through the strain relief. Wipe off the soap after the wires have been inserted.

Carefully push the frame cover "up" the wires and onto the jack frame as shown in the accompanying picture.

Thread the jack frame into the cover using care not to over-tighten - your jack should look like the picture to the right.

Next, use a pair of wire strippers to remove about 1/2" of sheathing from the end of each wire as shown.

Slide the protective boots for the alligator clips over the corresponding wires.

*** IMPORTANT *** Don't forget this step - once you solder the alligator clips to the wire, there's no easy way to get them on!!

Insert one of the wires into an alligator clip. Try to ensure some of the wire strands pass through the indented tab as shown. This will make is easier to solder the clip to the wire. Turn the clip over and spread/flatten remaining strands to make as much contact with the inside of the alligator clip as possible.

*** Reminder *** Before proceeding, make sure the protective boots for the alligator clips have not slipped of the wires!

Apply liquid flux inside and outside the alligator clip where the wire strands make contact - make sure to flux the bare wire strands as well. Use a clamp or set of "helping hands" to hold the wire and clip in place. Make sure the soldering iron tip is clean. Solder the wire to the alligator clip - note the clip and wire are very effective "heat sinks" so it may take a while before the solder will flow depending on the output of your soldering iron. Repeat the previous step and this step for the remaining wires.

Once the alligator clips have cooled, slide the protective boots up over the them as shown (you did remember to put the boots over the wires during an earlier step, right???).

Your controller adapter is now complete and ready for use!!

You can easily convert the adapter for use with Scalextric style mini plugs by using a 1/4" to mini adapter as shown. The adapter is included with the kit I offer.

Summary

There you have it!! This is a relatively easy project and the finished adapter is a great addition to your track or slot box.