Mains Power Conversion for Battery-powered Micro Scalextric

Some Micro Scalextric sets are mains powered, some are battery powered. If you find that you enjoy racing slot cars, replacing AA cells can get expensive, and not very ecologically friendly! This simple modification to the Power Base allows you to run your Micro Scalextric from a 9V DC plugpack adaptor. If an adaptor is not connected, it will continue to operate from its internal AA cells.

Parts

1. DC socket or "barrel jack." I used one from Jaycar: https://www.jaycar.com.au/2-1mm-bulkhead-male-dc-power-connector/p/PS0522 or a similar one from an international supplier: https://www.digikey.com/en/products/detail/mpd-memory-protection-devices/EJ501A/2439531
2. 2.5 mm heatshrink tubing
3. insulated hookup wire

Tools

1. Soldering kit
2. Flux
3. 8 mm drill

In summary, we need to break the connection between the internal battery and the hand controllers, to insert a power socket. The socket has an internal switch so that if no plug is in the socket, the socket is bypassed and the battery will supply power to the hand controllers. Depending on the socket, you can mount it wherever it fits in the Power Base. The following points are recommended, but not strictly necessary:

1. Use flux on all soldered joints. These shiny metal parts often do not accept solder well, but some flux will help the solder adhere to the metal.
2. Some heatshrink tubing on the tabs of the socket will add a bit of "strain relief" to you joints, and also insulate your work. I always use clear heatshrink so that the soldered joints can be inspected and to prove that I have nothing to hide :-)

1. Remove the 6 screws from the underside of the power base.
2. Remove the cover and keep the screws somewhere safe.
3. Refer back to this "before" picture if you make a mistake...

The plastic is quite brittle, so work carefully. Think about how much clearance you need behind your socket, then mark where you want to drill. I made a 2mm pilot hole before using an 8mm drill to make a hole to suit the socket.

The red circles in the image show the work you need to do. Don't forget to put a piece of heatshrink tubing over the wire before you solder the wire to the socket.

1. Screw the bottom cover back on to the power base. Make sure not to pinch any wires when you are replacing the bottom cover.
2. Attach a 9V DC power supply (about 1 amp should be enough, but if you go higher than 1 amp, you wont do any damage - the cars will only draw as much current as they need)
3. Enjoy never replacing batteries again.

You could add a switch to manually turn on/off power to your Micro Scalextric system. If a switch was present, you could also add an LED to indicate when the power is turned on.