Converting a SCX Compact Slot Car to Carrera Digital 143

By Michael Ashton

SCX Compact 1/43rd scale slot cars are among the best ready-to-run cars available in this scale. And although SCX has not released any new 1/43rd scale cars recently, they are still available in a few stores and on the Internet, if you are willing to search both diligently and persistently. I happen to have several SCX Compact NASCAR COTs that run quite well on the Carrera GO!!! track, so I would really like to add them to my growing stable of D143 cars. In order to do this they must be converted to the D143 system by installing the Carrera D143 decoder chip. This article is a brief step-by-step account of how this can be done.

Preparation

Look here to see a list of the minimum tools required for this type of conversion, tips on preparation and some cautionary advice that may help avoid mistakes. I rate this conversion as somewhere between low and moderate difficulty. Basic soldering and minimum modeling skills are recommended.

The Steps

After selecting a SCX Compact car to convert, and obtaining a Carrera D143 decoder chip/motor assembly, the first thing to do is compare a typical D143 and SCX Compact chassis side-by-side. This will allow planning to determine exactly where to create the opening for the D143 emitter and mounting post for the D143 circuit board.

The following photo shows a typical Carrera D143 chassis on the left and the SCX Compact chassis to be converted on the right. The D143 chassis does not have a decoder chip installed because the motor/chip assembly was removed and will be used in the SCX Compact conversion. There are three primary steps that must be accomplished for a successful, reliable conversion of the SCX chassis to D143:

1. An opening must be created in the chassis floor, in the correct location, that allows the emitter on the decoder chip to communicate with the sensor on the D143 lane change and lap counter track sections.
2. The decoder chip must be connected electrically to the pickup guide and motor terminals.
3. The decoder chip must be secured to the chassis floor so that no movement is possible.

Again, looking at the photo below, the yellow arrow points to the D143 chip mounting post which accepts a screw that holds the chip tightly in place. The red arrow shows the chamber which forms the opening through which the emitter communicates with the track sensor(s). In my opinion, the most secure chip installation and accurate digital performance will be achieved by duplicating these two structures in the SCX Compact chassis. So that is exactly what is going to be done here.

The Process

The first step in creating the opening for the D143 chip emitter is to determine the optimum location on the SCX chassis. The two important coordinates are: 

1. The distance from the center line of the chassis to the center of the opening. Ideally, we want the emitter to travel directly over the track sensor.
2. The distance from the leading edge of the guide flag (guide pin in the case of Carrera) to the center of the opening. The correct distance here ensures that the lane change flipper will activate prior to the arrival of the leading edge of the guide flag. Too long a distance could cause missed changes or even collisions with the lane change flipper.

In actual practice I have found these measurements to be not so critical. Just try to locate the opening as close to the position in the Carrera chassis as possible while still allowing for a secure chip installation and connection. The following two photos should provide a good depiction of where I drilled the hole in the SCX Compact chassis. Note that the leads that connected the motor to the copper strips leading to the guide pickups have been clipped.

To create the chamber for the emitter opening I used a short piece of 3/16” styrene tubing. The height of the chamber should be gauged to enable the D143 chip to sit level (i.e., no tilt) when the emitter is fully seated inside the chamber. Cut the chamber one or two mm higher than needed so that it can be adjusted by sanding the top after being glued in position.

The notch shown in the previous photo is needed because the opening in the chassis floor abuts the reinforcing rib that runs along the outer edges of the chassis. This allows the chamber to be centered on the opening without cutting the reinforcing rib and possibly compromising the structural integrity of the chassis. The chamber is glued in position using two-part plastic epoxy, mainly for that glue’s superior strength. See the photo below.

Below we see the finished chamber, sanded to the proper height and painted to match the chassis.

The mounting post is fashioned with a similar method. I used a short piece of 1/8” styrene tubing. Fist cut the tubing to the approximate height. Then use the D143 chip’s mounting screw to “self tap” into the post. Then remove and reinsert the screw several times until it is relatively easy to remove. Mount the loose post to the D143 chip through the chip’s mounting hole. Now you can test fit the position and height of the mounting post by seating the chip’s emitter into its chamber. Sand the end of the post, if necessary, to achieve the level orientation previously mentioned. Next, with the post still screwed to the chip, apply glue to the end of the post and place the post/chip assembly into position on the chassis floor with the emitter fully seated in the chamber. Apply pressure until the glue has set and then allow the glue to fully cure. Finally, gently remove the mounting screw and finish the post by applying epoxy all around the base. Painting to match the chassis is a finishing touch. The finished mounting post and emitter chamber are shown in the photo below.

Now that the D143 chip mounting structures have been created, it is a fairly straight forward process to install and connect the chip/motor assembly into the SCX Compact chassis.

Shown in the following photo is a typical D143 decoder chip/motor assembly. When converting a car to D143 my preference is always to use an existing D143 decoder chip/motor assembly when possible. The SCX Compact motor will work, but the D143 motor is known to be a good match for the decoder chip.

However, one characteristic of this assembly that presents a problem for installing in the longer SCX Compact chassis is how short the connecting leads are and, therefore, how close to the motor the chip resides. In the standard Carrera assembly, the positive output connection lead from the chip and one lead from the RF noise reduction capacitor are connected to the motor can as highlighted by the red arrow above. A common lead from the motor can, in turn, connects to the positive motor terminal. So all three wires are effectively connected to the positive motor terminal via the motor can.

Moving the chip’s positive output lead and the capacitor lead connections directly to the positive motor terminal, as shown in the following photo, allows the chip to be moved almost 1/2” farther away from the motor. This provides the additional flexibility in positioning required by the SCX Compact chassis.

Normally at this point the D143 chip’s input leads would be soldered to the copper guide pickup strips to complete the electrical connections. However, in this particular conversion I decided to install a quick connect micro plug assembly which allows the chip/motor assembly to be easily installed and removed. This allows the chip/motor assembly to be moved among different cars that have the plug assembly installed. This is a relatively simple process where the female (jack) is soldered to the chip’s input leads and the male (plug) is soldered to the copper pickup strips, as shown by the yellow arrows in the previous photo. If you don’t want to install the plug assembly, just solder the chip input leads directly to the copper guide strips.

The following photo shows the final assembly with the motor snapped into position and the D143 chip secured by the mounting screw with the emitter seated in the chamber.

This side view shows the emitter fully seated in its chamber (yellow arrow) and the chip sitting relatively level, secured by the mounting screw.

A view of the underside of the chassis shows the orientation of the emitter in the chamber.

One final recommendation: the SCX Compact cars perform very well on the Carrera GO!!!/D143 track. However, if your layout contains banked curves (as mine does), it will probably be necessary to eliminate the sharp square profile of the guide flag’s leading edge, as it tends to catch on the bottom of the slot on these track sections. The red arrow in the following photo highlights the SCX guide leading edge after being “nipped” and smoothed over with some light sanding.

So, it required a little effort, but I’m convinced that the final result was worth it. The SCX Compact cars in general look good, are quite true to scale and handle very nicely. If you are able to acquire, or already have one or more of these cars, and think that you would like to run them on a Carrera D143 track—go ahead. You won’t be disappointed.

A video of the SCX Compact Toyota COT converted in this article, running on a Carrera D143 track can be seen here.

_Michael Ashton

Carrera Digital: Creating a Digital 132 Ghost Car for Digital 143 Racing

By Michael Ashton

A feature of Carrera’s Digital 132 system that would really be nice to have in Digital 143 is the autonomous or ghost car. This is where a digital car can be programmed to run around the track at a constant speed while changing lanes in a random fashion. A recent article in this blog described how to implement an autonomous car in Digital 143 without any modification to the car or system and with virtually no added expense. However the method presented then has two drawbacks:

1. Each autonomous car created with this method requires a dedicated controller.
2. Lane changing follows the current state of the lane change flipper, so it is really not random.

This article will describe how to implement an actual D132 autonomous car that will run at a constant speed, change lanes in a random fashion and not use up one of the three available controller ID’s on a D143 track. This will be accomplished by installing a D132 decoder chip in a D143 car. A D143 controller can control car assignment, speed and lane changing through a D132 decoder chip. Furthermore, the D132 autonomous car feature can be programmed and works with the D143 system just like D132.

The terms “autonomous” and “ghost” are used synonymously throughout this article. 

The following photo below shows the components required to create a D132 autonomous car for the D143 system:

• A Carrera D143 motor, SCX Compact motor or a motor with similar specifications (do not use a Carrera GO!!! motor for this application).† The motor shown is an SCX Compact motor. The crown and pinion gears are identical to those used by Carrera, so the SCX motor is ideal for this conversion.
• A Carrera D132 digital decoder chip. Shown below is the #26740 chip used in Formula 1 cars. It has the smallest space requirement and is, therefore, most suitable for 1/43rd scale conversions.
• A Carrera GO!!! or D143 car chassis with motor and electronics removed. Shown below is one of the latest Carrera 1/43rd scale NASCAR’s.

Before proceeding there are a few points that should be made clear:

• Removing the motor and/or digital chip assembly from a Carrera GO!!!/D143 car and installing a D132 chip in its place may void the Carrera warranty. Test the car thoroughly in its stock condition prior to any modifications.
• It is possible that the use of a D132 chip with a motor designed for 1/43rd scale cars could affect the motor over time. This could be due to the fact that the D132 pulse width modulation (PWM) frequency is 15,625 KHz or, roughly half of the D143 frequency of 30.8KHz. This has the potential to increase the operating temperature in the 1/43rd scale motors, however, there is no conclusive evidence of this from testing.
• † There is also speculation that the motor installed in GO!!! cars is not appropriate for digital operation, with either D132 or D143. There is some empirical evidence to support this concern, therefore, only D143 or SCX Compact (which have a history of success in these implementations) motors should be used in digital conversions.
• This installation is not particularly difficult, however, basic skill and knowledge of soldering, and its attendant safety issues, are required.

Once ready to proceed, the first thing that must be done is to examine the chassis and decoder chip to determine how best to fit the chip to the chassis. Ideally, the existing sensor hole and mounting chamber of the D143 chassis can be used. This will insure that the sensor on the D132 chip will be in the correct position for the D143 track.

The Installation

The following two photos illustrate the test fit of the D132 chip.

The first photo reveals two potential problem areas when the D132 chip is test fitted with the sensor placed in the mounting chamber. First is the front edge of the chip encroaching over the front body mount receptacle.  Second is the upper motor lead terminal blocking the chip from being recessed down around the motor.

The second photo depicts in a side view how the height of the D143 chip mounting post also prevents the D132 chip (and its sensor) from being properly recessed toward the chassis floor.

After a little more tinkering with the position of the chip in the chassis, it became apparent that the major obstacle to an acceptable installation was the D143 chip mounting post. It appeared that if the mounting post could be lowered, that the chip could be “tucked” under the upper motor lead terminal and angled slightly to fit around the motor. So, the mounting post was dealt with first.

The next photo shows how the mounting post is trimmed with a sharp hobby knife to the same height as the sensor chamber.

This is the only modification to the cassis, so the piece cut from the top can be saved in case the car needs to be returned to its stock condition. However, I think that a D143 chip can still be properly mounted, in spite of the lower mounting post.

Before soldering any of the decoder chip lead wires to the motor or chassis, it is essential to “tin” the exposed wire ends by applying a small amount of solder as shown below. This makes it easier to solder the leads to terminals and copper strips by allowing the solder in the tinned wire and the terminal to flow together.

I believe that the best approach is to solder the chip leads to the motor while it is removed from the chassis. Purple is attached to the positive terminal. Note that the wire that connects the positive terminal to the motor can is left in tact. The gray wire is soldered to the negative terminal. When soldering leads from these digital chips and especially with these smaller 1/43rd scale motors it is important to use a low wattage soldering iron and to try to apply minimum heat by working quickly. Note: make sure that the slider switch (located on the underside of the chip as seen in the following photo) is set to the driver side of the chassis (i.e., toward the sensor).

Now the motor may be installed in the chassis motor mount. To install the chip, with the chip held in front of the motor, first slide the trailing edge of the chip’s main body underneath the upper motor terminal (see the yellow arrow below) and then ease the sensor all the way down into the sensor chamber. The chip will probably need to be tilted down toward the passenger side to do this. Work slowly and gently. When seated properly, the chip will reside at an angle but will fit well within the edges of the chassis, and sitting flat. The good news is that, in this configuration, the front edge of the chip does not interfere with the front body mounting post, as highlighted by the red arrow. Now go ahead and solder the input leads to the guide terminals. Black to the positive (driver side) and red to the negative (passenger side). The finished installation is shown below.

The yellow arrow in the photo below shows a small strip of electrical tape used to insulate the surface of the chip where it is tucked under the upper motor terminal. The combination of the sensor residing inside the sensor chamber and the chip fitting snug under the motor terminal provides a very secure mounting of the chip.

Finally, check the orientation of the sensor in the mounting chamber through the hole in the cassis. It should look as depicted below.

The Setup

I recommend first programming the car to one of the three controller ID’s then running the car briefly to test throttle control and lane changing. The converted NASCAR worked fine. One thing that should be noted is that the D132 chipped car now has dynamic braking. With the full D132 system (Black Box or CU) the brakes are adjustable, however, this is not the case with the D132-chipped car running on a D143 track where the braking effect is always at maximum. The combination of strong brakes and high magnetic down force may not be desirable. Regardless, when used strictly as an autonomous car this is not really an issue.

To program the D132-chipped car for autonomous operation the steps are as follows:

1. Place the car — with no other cars — on the track.
2. Depress the lane change button on the speed controller two times in rapid succession.
3. Lift the front of the car (i.e., pickup braids) out of the slot.
4. Replace the front of the car into the slot.
5. Depress the lane change button on the speed controller four times in rapid succession.
6. Depress the throttle (plunger) until the desired speed is attained.
7. While maintaing the desired speed, depress the lane change button one time.
8. The car will now run at the selected constant speed and will change lanes randomly.

The following excerpt from the Carrera Digital 143 user guide depicts these steps (click to enlarge):

Try to set the speed so that the autonomous car can handle every curve while also not hesitating on the lane changers’ dead spots.

This definitely takes ghost car racing on a Carrera D143 track to the next level. The installation of the D132 decoder chip may be more than some casual users will care to attempt because it does require a basic level of soldering skill. However, I can attest to the fact that a relatively small amount of time and effort will yield an enormous reward of racing versatility and fun. Especially for the “solo” racer.

Thanks to Brian at BRS Hobbies for providing the resources to make this article possible.

Note: Just prior to publication Carrera released the 42013 Wireless Digital 143 2.4 GHz Controllers (and power base). These controllers allow any D143 car to be programmed for autonomous operation, including random lane changing. Each autonomous car requires a controller. A future article in this blog will cover this product. — Ed.

_Michael Ashton

Creating a Ghost Car for Carrera DIGITAL 143 Racing

By Michael Ashton

I really enjoy racing on the Carrera Digital 143 track when I am fortunate enough to have someone to race with. Unfortunately there are no other slot racing enthusiasts located within hundreds of miles of my home, so I only have a few months out of the year that I can actually race with other people when a couple of friends come to my area for the winter. The rest of the time is spent tinkering and running cars alone.

A nice feature of Carrera’s Digital 132 system that would really be great for a “lone wolf” racer like myself is the autonomous or ghost car. This is where a digital car can be programmed to run around the track at a constant speed while changing lanes in a random fashion. I like to call it a nuisance car because its purpose is to make the racing more interesting and exciting by causing traffic jams, getting in the way of the human-operated cars and acting like, well… a nuisance. So, if there is no one else to race with, you can race against (or around?) the nuisance car.

It's too bad that this feature is not available in the D143 system. Nevertheless, there is a way to simulate the ghost car function on a D143 track. And it requires absolutely no modification of any system component and virtually no additional expense. We’ll name it the D143 Ghost Car and note that the lane changing capability is made possible by a design characteristic of the D143 lane change track. So first, a little background on the operation of the lane changer:

The first photo below shows the lane changing mechanism or, flipper, depicted by the yellow arrow. The flipper is in its closed or, “no change” position. Cars passing over the receptor, shown by the white arrow, with the speed controller’s lane change button not depressed, will continue in the current lane.

The next photo shows the flipper in its open or, “change” position. The flipper shifts to this state when a car passes over the receptor with the speed controller’s lane change button depressed. The car will be diverted into the crossing slot and change to the opposite lane.

A very interesting characteristic of the operation of this mechanism, which I think is unique to the D143 system, is that the flipper is not spring loaded (i.e., it does not spring back to the closed state). Instead it remains in the change state until a car passes over the receptor with the speed controller’s lane change button not depressed, at which point the flipper returns to the no change state, allowing the car to remain in the current lane. However, if the next car passes the receptor with the speed controller’s lane change button depressed, the flipper remains in the change state and the car changes lanes. It is this characteristic that allows a pseudo random lane changing function to be implemented.

The Setup

The emitter that triggers a lane change is located on the underside of the D143 car’s chassis. All that is required is to cover this emitter so that it cannot be detected by the receptor in the lane change track and the car will not change the state of the flipper. It is now, in effect, a D143 ghost car. This means that if the preceding car has set the flipper to change, the D143 ghost car will also change. If the preceding car has set the flipper to no change, the D143 car will continue in the current lane. In effect, it will obey the current state of the flipper, regardless of any action of the speed controller’s lane change button. Although the lane changing action is not truly random, it will be difficult at best to predict the action of the D143 ghost car while concentrating on the human-driven car.

In the following photo, a circular red sticker has been placed over the car’s emitter opening, indicated by the yellow arrow. The emitter is recessed into the chassis enough so that adhesive from the sticker should not contact the surface of the emitter as long as the sticker is not pushed into the opening. Masking tape could also be used for this purpose. Note that this will also prevent the car from registering laps on the D143 Lap Counter.

Now that we have lane changing, we can turn our attention to the other aspect of the ghost car — speed control. As with lane changing, the method used to implement speed control is low-tech, virtually cost-free but surprisingly effective. Yes, the following photo shows an external continuously adjustable variable throttle pressure device. Also known as a rubber band (see the red arrow). OK, I can hear the sniggering in the background, but this method works very well. There is just enough friction in the throttle plunger to enable the speed adjustment to hold reliably — even as fine adjustments are made. The yellow arrow points to the GO!!!/D143 throttle governor which also helps maintain the throttle position while limiting maximum speed to something that is manageable. Of course you will need to experiment with different sizes and thicknesses of rubber band in order to achieve just the right downward pressure on the plunger.

Now, just place the D143 ghost car in either slot, turn on the power and it will start immediately. Once you find the correct length and thickness of rubber band you should be able to fine tune the throttle position to achieve a speed that suits your specific need. I find setting the speed so that the ghost car can handle every curve while also not hesitating on the lane changers’ dead spots works best for me.

Next, place a human-controlled D143 car in the slot and just start running. As you run and start to change lanes the ghost car will follow the state of the lane change flippers. It won’t be long before the interaction between the two cars will start to reveal situations that will make the running more interesting. For example: eventually the human-controlled car will end up behind the ghost car and a lane change will be required in order to pass; or the human-controlled car can change lanes while just behind the ghost car and then try to time each subsequent lane change so that the cars are always crossing paths and never in the same lane; or just see how many times the human-controlled car can lap the ghost car. There are likely many different scenarios to be discovered and I’m still experimenting.

Perfect? No. Effective? Yes. Fun? Absolutely!

Some things to consider about this method of implementing a ghost car capability:

• There are some drawbacks. The primary disadvantage being that, unlike a true ghost car function, the D143 ghost car requires a controller and uses up one of the three available car ID’s. Personally, I don’t see this as a major issue because, at least in my case, the motivation for doing this is to make racing alone more fun. Also, there is no way to start and stop the ghost car while the controller is set using the rubber band. This means that there cannot be a true starting grid, unless the power is off and then switched on to start the race. Once again, not a big issue for me personally.
• If the D143 ghost car becomes obstructed by a de-slotted car or pileup, be aware that the throttle will continue to apply power. For this reason it is best to clear any obstructions to free the ghost car in a timely manner.
• At the present time I have only two D143 controllers so my testing has been limited to a single (solo) human-controlled D143 car. However, even in this somewhat limited configuration the D143 ghost car significantly enhances the digital racing experience. There is no doubt that running the D143 ghost car with two human-controlled cars would really provide some exciting and challenging racing.
• If a second D143 ghost car is desired it could be created easily by adding a third controller and setting up another D143 car as a ghost car as previously described. However, a superior set up for a solo D143 racer wanting multiple ghost cars could be achieved by installing a D132 decoder chip in a GO!!! or D143 car. The D132 decoder chip can be programmed via the speed controller to run at a constant speed and change lanes randomly on a D143 track. This would enable a fully functional D132 ghost car, a D143 ghost car and a human-controlled D143 car to all run concurrently managed by a single racer. An advantage of this approach is that only two controllers are needed because the programed D132 ghost car uses ID 7. Therefore, the original three D143 ID’s (1,2 and 3) are still available. A future article dealing in detail with the installation of a D132 decoder chip in a GO!!!/D143 chassis will appear on this blog in the near future, so be sure to check back from time-to-time.
• One way to make D143 racing against ghost cars more challenging is to reduce or even eliminate the magnetic down force provided by the traction magnet in the human-controlled car’s chassis. This will make the human-controlled car a little more difficult to control in the turns and will also require an increased level of concentration and skill on the part of the solo racer. Down force can be reduced incrementally by adding thin plastic shims under the magnet in the magnet chamber. Or, the traction magnet can be removed, in which case an aftermarket rear tire such as Jel Claws will be needed in order to provide at least minimal traction on the smooth surface of the Carrera track. If down force is reduced even partially, it will be important to keep the rear set of pickup braids pushed in to a shorter length and possibly splayed a little wider. This may be necessary in order to avoid shorting of the track rails if the car’s rear end slides out in the turns. Setting a car up to run this way will also be discussed in detail in another future article right here.

So, in conclusion I will say that if you spend any significant time running your Carrera Digital 143 slot cars by yourself, you should definitely try this method of adding ghost car(s) to your racing environment. I found it to be very worthwhile and a big step up from merely counting and timing laps when there is no one else to race with. And it requires no modification to the cars, track or any other D143 component, and there is virtually no additional cost other than a sticker and rubber band. There is really nothing to lose.

Thanks to Brian at BRS Hobbies for coming up with this neat idea and making this article possible.

_Michael Ashton

Disabling the Turbo Button on the Carrera GO!!! Controller

By Michael Ashton

The standard Carrera GO!!! controller comes with a feature called the Turbo button, highlighted below by the red arrow. The controller's thumb trigger provides between 0% and about 70% of the available power to the cars. Depressing the Turbo button provides 100% of available power immediately. This feature tends to work fine on medium to large tracks with moderately experienced racers running the cars. But on a small track with novice racers or children, the sudden burst of power can be too much for them to handle. Moreover, the button is in a position where it could be activated by accident. This might lead to frustration for someone who is just getting started in the hobby. Therefore, it would be nice if the Turbo button could be disabled or removed. The good news is that it can, very simply, and without the need for any permanent modification to the controller. And the only tool required is a small to medium Phillips screwdriver.

In order to disable the Turbo button the controller's housing must be opened. To do this, unscrew the two Phillips screws shown by the yellow arrows in the photo above. Then gently pry to two halves of the controller housing apart, lifting the half that is facing up away from the lower half. The controller will look as depicted in the following photo. The yellow arrow points to the Turbo button mechanism, which will be removed, thereby disabling the function.

Once the controller case has been opened, lift the lower end of the Turbo button up and out of its pivot hole as shown in the following photo.

Next, carefully lift the throttle plunger assembly upward and away until it separates completely from the controller case as shown in the photo below. The Turbo button can then be gently wiggled off the plunger shaft. The yellow arrow highlights the plunger return spring. I am holding it in place with my index finger because it has a tendency to fly off the shaft and hide under anything nearby.

Now replace the plunger assembly in the reverse manner that it was removed. See the following photos. The yellow arrow in the first photo below highlights the throttle contacts. They must straddle both sides of the red guide that runs between the two sets of resistor wire windings, visible just below my forefinger.

Getting this assembly back in can be a little tricky so proceed slowly and carefully. The return spring should go into the plunger channel first with the upper part of the plunger tilted way from the controller case. It is necessary to depress the contacts so that they will fit around the red guide (see the red arrow below) and the shaft can be moved downward into position until it is below the upper stop (shown by the yellow arrow).

Replace the upper half of the controller case, making sure that the cable is positioned in the hole at the bottom of the controller and is not pinched or stressed in any way (see the red arrow below). Once you are sure of the fit, reinstall the two screws.

The left hand photo below shows the reassembled controller without the Turbo button. Note the opening where the button used to be. This did not present a problem for me because my fingers were large enough to fit over the opening without slipping inside. However, this is likely to be a distraction for smaller hands such as those of a child. A simple solution to guard against this is a small strip of electrical tape over the opening as show in the photo on the right.

Once the case is opened on an electronic product it is possible that any remaining warranty becomes void. Also note that the controller is now only capable of delivering about 70% of available power to the car, which may affect the ability to traverse the loop accessory if there is not a sufficiently long straight section leading into it.

In any event, following the procedure outlined above, the Turbo button of the Carrera GO!!! controller can be disabled simply, safely, reliably and with no permanent modification of any kind to the controller. This will undoubtedly help the younger enthusiasts get more enjoyment out of the racing — and that's what this is really about. Just be sure to store the Turbo button mechanism in a secure place and the controller can be restored to its original condition very easily.

_Michael Ashton

Converting the Carrera GO!!! Dodge Viper to Digital 143

By Michael Ashton

I have a Carrera GO!!! Dodge Viper that I would like to race on my D143 track. This entails installing a D143 decoder chip in the Viper. Technically, this is not an overly complex task, however, the larger obstacle is the fact that the D143 decoder chip is not available as a separate product from Carrera. This means that the only source for a D143 chip is an existing D143 car. Fortunately, I happen to have a D143 Ferrari F12 Berlinetta "street" car that I do not need for digital racing. Therefore, the Ferrari will become the "donor" vehicle. The D143 chip in the Ferrari will be transplanted to the Viper and at the end of the process, the Ferrari will become a GO!!! car — nothing wasted here.

Preparation

Below is a photographic list of the minimum tools required to remove and install the decoder chip:

1. A relatively low wattage (≈ 30 watt) soldering iron.
2. A hobby knife with a fresh, sharp blade.
3. A scribe or hole punch (a sharp nail will do).
4. A small tip Phillips screwdriver.
5. A 1/8" and a 5/16" drill. 

The above tools will allow the task to be completed successfully. Naturally there are additional tools which can make the job easier, quicker and the results more professional. These tools will be pointed out later in each step of the process where they are used.

Let's take a look at a side-by-side comparison of the GO!!! and D143 chassis.

Below right is the D143 chassis with the chip installed. The yellow arrow highlights the screw that holds the chip firmly in place. The red arrow indicates the point where the lane change LED emitter fits inside a cylinder that forms the opening through the underside of the chassis. It is through this opening that the emitter sends the lane change signal to the sensors in the lane change track section. The inset photo shows a closeup view of the LED emitter seated in the cylinder, indicated by the red arrow.

Above left is the Carrera GO!!! Viper chassis that will receive the D143 chip. Installing a D143 chip into a GO!!! chassis is made much simpler by the presence of the D143 chip mounting post that will be used to secure the chip in place with the mounting screw (yellow arrow), and a solid plastic post into which a hole will be drilled to create the opening for the lane change LED emitter (red arrow). Both posts are in the correct position required for accurate communication between the emitter and track sensors, so no measuring is required.

A few cautionary notes:

• It is quite possible that the modifications described in this article will nullify any manufacturer's warranty that may still be in effect. It is, therefore, important to test the digital functionality of the donor car prior to proceeding in order to insure that you have a good D143 decoder chip.
• This conversion is not particularly difficult, however, basic skill and knowledge of soldering, and its attendant safety issues, are required.
• It is strongly recommended that when transplanting a D143 decoder chip from one chassis to another that the chip/motor assembly be removed and installed as a unit. This will preclude the need to de-solder and then re-solder the chip connectors to the motor terminals, thus averting the risk of overheating the chip components and/or the motor itself. It also insures that a motor with the appropriate specifications for digital operation is used.

The Steps

1.) Remove the bodies of both cars from their respective chassis by unscrewing the mounting screws located at the front and rear of the underside of each chassis.

2.) Remove the D143 chip from the donor chassis.

a.) First, de-solder the motor lead wires from the pickup contacts (see the following photo):

Additional tools employed here are a soldering stand, used to free both hands by holding the chassis in place, and a pair of surgical forceps to pull the lead wires from the pickup contacts when the solder melts. Note that the front tires have been removed to avoid damage from the soldering iron tip. The front wheels were not removed because the front axle tips are knurled. So removing the wheels would likely have caused irreparable damage to the hubs. Exercise caution when soldering near these wheels.

b.) Remove the decoder chip mounting screw, as shown in the photo below.

c.) To remove the motor/chip assembly, first gently push the hole punch or a small flathead screwdriver through the opening of the motor mount on the underside of the chassis, as seen below. Repeat in the opening on the other side of the motor mount. Take your time and do this gently in order to avoid damaging the motor mount tabs that secure the motor in place.

This will cause the motor/chip assembly to pop up out of the motor mount, shown in the following photo. The assembly can then be lifted up and forward, separating it from the chassis. The red arrow points out the LED emitter.

Below is the motor/chip assembly, safely removed from the donor chassis. Note the tabs at the front of the motor mount (just behind the chip mounting post), still in tact.

d.) Repeat the above steps a.) and c.) to remove the motor from the GO!!! Dodge Viper. The difference is that there is no decoder chip to deal with.

3. Prepare the Dodge Viper chassis to receive the D143 decoder chip.

a.) Drill a small pilot hole in the center of the solid post that will house the LED emitter. I used a pin vise and a very narrow diameter drill as shown below. But the hole punch or even a small sharp nail can be used.

Absolute precision is not necessary, but try to be as close to the center of the post as possible.

b.) You could probably drill the final hole now, however, if you have a drill set, work your way up to the final hole size in several gradual increments. This will make the drilling easier and is less likely to cause damage.

c.) Use the 1/8" drill to create the final opening in the top of the cylinder. Drill all the way through the chassis turning the drill by hand — do not use an electric drill for this. See the following photo.

The finished opening as seen from the top is shown below. The hole is not perfectly centered but this is not a problem because the LED emitter and the lane change track sensors have a relatively wide angle of sensitivity.

e.) The underside of the opening is shown in the photo below. Note that this side of the opening is slightly larger than the top, or beveled. This is accomplished by drilling up from the bottom by about 2 mm with the 5/16" drill. Be very careful not to drill too far up. The edge can be smoothed over using the hobby knife and some fine sandpaper. This is an important step because the beveled opening provides a wider field of transmission for the LED emitter.

3.) Install the D143 chip/motor assembly.

Just reverse the steps of motor/chip assembly removal from above. Slide the pinion gear through the circular opening in the mounting bracket in front of the crown gear until it meshes properly with the crown and the motor shaft fits into the channel between the two parts of the gear. Make sure that the LED emitter is lined up to fit into the cylinder opening. Then press downward on the motor can and chip until the motor snaps into place and the LED is seated into the cylinder. Insert the mounting screw through the hole in the chip and into the mounting post below, then turn the screw all the way down until it is tight and the chip is firmly seated and the LED is all the way into the cylinder. Finally, solder the motor lead wires to the pickup contacts.

The two photos that follow show the motor/chip assembly installed in the Dodge Viper chassis. Note the orientation of the motor lead wires for correct polarity. The red arrow in the first photo highlights the proper positioning of the LED emitter.

When viewed from the underside of the chassis, the emitter should appear as shown in the photo below.

The GO!!! motor removed from the Dodge Viper can be installed in the Ferrari in virtually the same manner as depicted above for the Viper. Again, the only difference is that there is no decoder chip and LED emitter to deal with.

Finally, reinstall the Dodge Viper body onto the newly converted chassis and we now have a D143 Viper ready to test on the D143 track.

The newly converted D143 Doge Viper was tested on an oval skid pad for about 100 laps of continuos lane changing and straight pass throughs. During this test there were no missed or spurious lane changes observed.

Upon completing this project a couple of things occurred to me: first, the Dodge Viper is available only as a GO!!! car, so I now have a D143 Viper which is somewhat unique; second, apparently GO!!! cars are pretty easy to sell on Internet auction sites and slot car forums. So if there is no need for the [converted] GO!!! donor car, this will help reduce the overall expense of the conversion significantly. Somewhat cool on both counts, I think.

_Michael Ashton