I have always managed to live in places that can only be characterized as a slot car 'wasteland'. By that I mean that no one else within a hundred miles is involved in the hobby. No one to race with or tinker with the cars. Anyway, I recently moved from Southwest Florida to North Central Florida, effectively replacing one slot car wasteland with another. Naturally I assumed that my lonely isolation in the slot car hobby would continue. So you can imagine my surprise, followed by overwhelming joy, when I received a message through an Internet slot car forum from Ray.
Ray is a 1/32nd scale slot car enthusiast — just like me! Ray has a digital slot car track — just like me! Ray lives less that 30 minutes from me! I could not believe it. Another DIGITAL slot racer less than 30 minutes away! I thought that I was going to explode. But wait. Ray’s track is Scalextric Sport Digital (SSD) while my track is Ninco N-Digital. The two systems are not compatible, therefore, he can’t run his cars on my track and vice versa. Unless we are both willing to install digital decoder chips from the other system in our cars, we would have to borrow cars when visiting each other’s track. Not a terrible solution but I would be hesitant to race another person’s cars really hard in case I break something. And we would like to race our own better cars — not just beat up 'runners'.
Ah, but there is hope. For quite a while now most Scalextric and Pioneer slot cars come with a chassis that is designed to accept the Digital Plug Ready (DPR) Easy Fit decoder chip. Shown in the following photo, the DPR chip is mounted on a removable panel that fits into the underside of the chassis just behind the guide. The car is equipped at the factory with an analog version of the panel that passes power through directly to the motor terminals. Converting the car to digital is a simple matter of removing and unplugging the analog panel and replacing it with the DPR chip — without having to remove the car’s body. Truly plug and play.
So, I got to thinking, what if there were an N-Digital version of the DPR chip? That would allow Ray and me to run all of our DPR-equipped Scalextric and Pioneer slot cars on SSD, N-Digital and analog tracks without any modifications to the cars. All that we would have to do is plug in the appropriate DPR chip or the analog panel. Well, the only way an N-Digital DPR chip was going to exist is if I were to create it. So I did!
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The remainder of this article describes the necessary steps to fabricate an N-Digital DPR chip and what I learned in the process. The N-Digital DPR chip is a relatively simple DIY project with the only requirement being basic soldering skills. Tools and materials needed are:
- Low wattage (30 watt) pencil type soldering iron.
- Solder removal tool (solder sucker).
- N-Digital decoder chip (any version of the chip will work).
- Analog panel from a DPR-equipped Scalextric or Pioneer car (see the following photo). The white DPR plug must be removed and will be wired to the N-Digital decoder chip.
- Narrow heat shrink tubing for the lead wire connections to the DPR plug.
- 9 - 10 mm heat shrink tubing to protect the entire DPR plug assembly.
- CA adhesive (super glue).
- Two part plastic epoxy adhesive.
- Double sided adhesive foam pad or tape.
The first step is to remove the housing which contains the white four-pin DPR plug from the analog panel. This is easily done using the blade of a sharp hobby knife to loosen and pry the housing away. The DPR plug is removed from the housing in the same manner. Just be gentle and patient. The DPR plug, freed from the analog panel housing is shown in the photo below.
The red arrows point to the plug’s two pairs of input/output pins which are soldered together for analog operation. The solder on these pins must be removed by heating them with the soldering iron and then using a solder sucker to pull the solder away from the pins. The resulting plug should look as shown below.
The DPR plug is now ready to be connected to the N-Digital chip’s lead wires, however, the pins may be somewhat loose, allowing them to move inside the plug. Applying a small amount of viscous CA adhesive (super glue) to the base of each pin will keep them secure in their position.
The following two illustrations identify the pin positions of the DPR plug and the corresponding lead wire positions of the N-Digital chip. It is just a matter of soldering the N-Digital chip’s '+ guide' lead wire to the DPR plug’s '+ guide' pin, then the '- guide' lead wire to the '- guide' pin and so forth.
DPR Plug N-Digital Chip
Cut the N-Digital lead wires to a length of about 20 mm. Then strip and tin the ends of each trimmed lead wire with solder. Before soldering to the pins, slip a 1/4” length of narrow heat shrink tubing over each lead wire. Now solder each lead wire to the pins according to the position identifications shown above. Push the shrink tubing over each solder connection so that it is completely covered and shrink the tubing using the hot soldering iron. Next, cut a 15 mm length of the larger (9 -10 mm) heat shrink tubing and push/stretch it over the whole DPR plug assembly. Shrink that tubing until it appears as shown in the photo of the finished project below.
One last point: the solder connections of the N-Digital chip lead wires to the printed circuit board (PCB) are notoriously fragile. I mixed some two part plastic epoxy adhesive and applied it to the base of each lead wire's connection to the PCB to form 'boots'. This will keep the lead wires from bending and being stressed at the solder joint. Finally, the finished N-Digital chip/plug assembly is attached to the DPR panel using double sided mounting foam tape or pads. The mounting pads suppled with the N-Digital chip are ideal for this.
The N-Digital DPR chip is shown below being installed in a Pioneer Camaro. This car has a full interior and somewhat restricted space above the DPR panel and the N-Digital DPR chip still fits quite easily. The chip has been installed and tested in a small but representative sample of Scalextric and Pioneer cars without any problems in either installation or performance.
So, if there are any N-Digital users still hanging in there, and you have a few (or a lot of) Scalextric and/or Pioneer cars that are DPR ready, then you may want to make one or two N-Digital DPR chips. It’s a fairly easy project that provides benefits that are more than commensurate with the time and effort required. At least Ray and I think so. We now have a small fleet of cars that is easily switchable among SSD, N-Digital and analog racing, without even having to remove the car’s body. All we have to do now is find the time to race.
_Michael Ashton
