“Dad, can we get your old slot cars out?”

“No.”

“Dad, can we get your old slot cars out?”

“No.”

“Dad, can we get your old slot cars out?”

“No.”

…This conversation repeated itself every day for about a month before I finally broke down and dug my old slot car sets out of the basement. Pretty soon after that, my kids had set the track up on the floor, all hooked together and ready to go.

Problem was, the slot cars wouldn’t budge—when you pulled the triggers, you didn’t get a single sputter, sound, or spark.

So instead of getting to enjoy scale racing action with an awesome slot car set, I sulked down to my basement clutching some loose track, and began troubleshooting why these slot cars wouldn’t go.

slot car scale comparison
Slot cars come in a range of sizes (scales), and they often use distinct track and pickup designs. But the troubleshooting steps outlined in this article generally work for pretty much any type you’ll come across. (Image/OnAllCylinders)

What to Do if Your Slot Cars Don’t Run

The good news here, is that after some easy troubleshooting, the problem was traced to a series of compounded issues involving both the slot cars and the track itself. And even better, once those problems were addressed, the slot cars were racing around the track like they did when they were new.

That said, here’s a quick slot car diagnostic procedure to help you out.

You may enjoy this article too: 5 Things Model Trains Teach You About Wrenching on Cars

vintage slot car boxes arranged on floor
Many of these slot car sets date back to the early 1980s, but thanks to the maintenance and diagnostic tips below, they’re still working well into 21st century. (Image/OnAllCylinders)

***

Troubleshooting Your Slot Car Track in 3 Easy Steps

Diagnosing slot car issues can be broken down into three elements: the power supply, the track, and the cars. And more importantly, if you inspect them in the proper order, you’ll probably get to the source of the issue pretty quickly. Here’s how.

1. Check the Slot Car Power Supply

For starters, you’ve got to make sure your power supply is good. And while “wall wart” style AC adapters are usually pretty durable, the wires and connectors that link them together can be common culprits of a slot car no-go scenario.

back of a slot car AC adapter
Looking at this particular AC adapter’s output, we see that it should crank out about 20 volts DC at five amps. (Image/OnAllCylinders)

To do any serious testing here, you need a good electrical multimeter. Looking at the back of the AC Adapter, I saw it output DC voltage, so I set up the multimeter accordingly. Glancing at my other slot car sets, they all pretty much used similar low-voltage DC power sources—but check your specific slot car set to make sure you know what power you’re looking for.

slot car ac adapter check
First, I checked the AC adapter right at the terminal connector. It read around 19.5 Vdc, which was close enough to spec. (Image/OnAllCylinders)
slot car trigger power check track, power off
Then I plugged the power into the track’s special terminal track section and clipped a set of alligator leads to the metal contact strips embedded in the track. With the throttle trigger released, the multimeter barely registered anything—which is correct, as gradual power is delivered as you pull the trigger. (Image/OnAllCylinders)
slot car trigger power check, power on
With the trigger pulled (via rubber band here) we see that the track is getting full power. (Image/OnAllCylinders)

Using the quick diagnostic steps shown in the pictures above, we determined that everything was hunky-dory with the power supply, the controllers, and the track terminals. That meant it was time to go the next step, the slot cars themselves.

2. Check the Slot Car(s)

Not gonna lie, I was notoriously hard on my toys as a kid, so I wasn’t surprised to see some serious wear-and-tear on the cars. And since the cars wouldn’t budge at all, even with a good power supply, I suspected that the biggest problem was with the cars’ pickup shoes as they made contact with the metal conductor strips embedded in the track.

A close inspection confirmed it:

close up of slot car contact plates
On the left was the lesser-worn car, still with its original contact shoes. The car on the right is wearing brand new replacement strips, and you’ll see why in the next pic. (Image/OnAllCylinders)
new and old slot car contacts on table 2
Removed from the car and resting alongside new ones, you can see the contact shoes on the right have serious wear. In fact, the one near the center has a hole worn straight through the copper. (Image/OnAllCylinders)

Whoa nelly, both of the car’s pickup shoes had deep grooves cut into the copper, and the left side contact strip was worn clear-through. Fortunately, these Tyco-derived slot cars are common, and replacement pickup strips were quickly sourced and replaced.

In many cases, complete replacement slot cars are available too.

close up of slot car contact braids
Not all slot cars use pickups with a copper strip. Specifically, some of the larger cars feature a metal braid to make contact with the track conductors. While they’re often replaceable, you may find that cleaning and repositioning the braid will quickly bring the car back to life. Another tip: slightly fray and fan the tip of the braid where it meets the track for better contact with the metal conductors. (Image/OnAllCylinders)

3. Check the Slot Car Track Connections

With the cars repaired and the power supply testing OK, I went back upstairs to try again. I placed one car on the track, pulled the trigger, and it buzzed to life…

…but only made it about halfway around the track before slowing to a stop.

I moved the car back to the starting point and tried again, with the same results.

That told me that the car was now OK, but the track was slowly losing continuity between the track sections.

close up of slot car track connection
You can see the metal conductors in the track are merely a press-fit between track sections, so making sure there’s a strong connection and clean contact points is critical. (Image/OnAllCylinders)

I unhooked each track section and, using a small(!!) amount of electrical contact cleaner and a Q-tip, I cleaned each metal tab of the conductor strip.* Then I pressed the track pieces together to ensure a snug fit.

* Depending on the type you use, electrical contact cleaner can be some gnarly stuff—akin to brake or carburetor cleaner. While it’s very effective at cleaning electrical connectors, it also means that it can dissolve paint, etch plastics, permanently stain finishes, and do other nasty damage. Always use it sparingly, quickly wipe up any excess, and be extra, extra careful when spraying it around to avoid marring or blemishing the surrounding areas. (If you’re spraying around really sensitive spots, like electric guitar pots and amp tube pins, check out Caig DeoxIT. Yeah, it’s pricey, but effective and safe.)

With the track reassembled, both cars could now make complete circuits around the course. But it still seemed like the track had some “dead” spots where the cars broke electrical contact with the track. Sure enough, when I looked closer, there was some obvious surface oxidation on sections of the track’s metal conductor strips.

Using a foam-backed sanding block (the type often used in drywall jobs), I gently ran across the entire track—using very, very light pressure to ensure I only removed the slight layer of surface corrosion. Too much force here, and you could easily wear down the metal conductors in the track, rendering it inoperable.

using drywall sanding sponge on slot car track
The foam sanding block alleviated pressure on the track, which helped me avoid damaging the thin metal strips. Remember to be gentle here! (Image/OnAllCylinders)

Once I got done gently running the sanding block over the entire track, I sprayed some mild degreaser on a rag and wiped it all down again.

With that, I set both cars on the track and fully squeezed the triggers simultaneously…

…sending both cars flying into my drywall. Facepalm.

Undaunted, I quickly tempered my throttle grip and, within a minute, both cars were racing along like new.

Regular Slot Car Maintenance

With the slot car track refreshed, there are some basic maintenance procedures that’ll keep your slot cars running well. But it doesn’t require a whole lot of imagination—it all basically boils down to regular cleaning.

Get a closer look in these pics:

cleaning bottom of a slot car with contact cleaner
Remember, a strong contact cleaner can damage plastics, paint, rubber, and other soft parts. Always use it sparingly and it’s often best to spray it on a small Q-tip for a precise application. (Image/OnAllCylinders)
cleaning bottom of a slot car
In addition to the magnets in their electric motors, many slot cars rely on some sort of magnet to keep them secured to the track. That means the cars will pick up tiny bits of any magnetic material as they race around the course—along with plenty of carpet lint, dust, and pet hair. An occasional cleaning with some mild degreaser and a regular wipe down are critical. (Image/OnAllCylinders)
cleaning a slot car power input port with a q tip
Make sure to occasionally clean the terminal ports for the track as well, and do the same for the female connectors on the controllers and power supply too. Corrosion and gunk can build up, creating electrical resistance that’ll hinder the cars’ performance. (Image/OnAllCylinders)
drywall sanding sponge and scotch brite pad on table
Foam-backed drywall sanding blocks, typical dishwashing sponges, and trusty Scotch-Brite scuffing pads are all effective at removing corrosion from the track conductors—just don’t use too much pressure or you risk damaging the track by excessively wearing down the metal track leads. (Image/OnAllCylinders)
vintage slot car tune up kit
While I got lucky in this scenario, as the no-go issue was linked to easily-fixed electrical contact problems, bent axles, stripped gears, and old, crumbling tires are also common trouble areas. The good news is, replacement slot car parts are often easily sourced online and in the secondhand market. (Image/OnAllCylinders)

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Author: Paul Sakalas

Paul is the editor of OnAllCylinders. When he's not writing, you'll probably find him fixing oil leaks in a Jeep CJ-5 or roof leaks in an old Corvette ragtop. Thanks to a penchant for vintage Honda motorcycles, he spends the rest of his time fiddling with carburetors and cleaning chain lube off his left pant leg.