Carrera controller 61511 repair

A few years ago my sons got a Carrera Go race track for Christmas, and unfortunately some time back we observed that the turbo button does not work reliably anymore (which made especially the loop track almost unusable). I found several reports on the Internet that this is a common problem, but I did not find any repair reports yet, so I decided to have a further look into it and see if it is possible to repair this.

First, after opening the controller, I quickly saw what the problem is – the switch is simply broken (in this picture there is also a spring missing which just fell out):

I tried to fix the broken piece by soldering it together again, but this did not work. So the switch was essentially broken and needed a replacement. However it seems that this is a very special part and I did not find any identical replacement for it. However I thought that maybe it is possible to use one of those more common microswitches instead, and decided to give it a try.

First, I pulled out the pcb and removed the defective switch (the pcb is only fixed by two plastic pins, and the switch is not even soldered to the pcb so that it can easily be pulled out after desoldering the two wires):

I then had to adjust the lever by removing a piece of plastic from it, because the new switch is slightly larger. Then, I could do a first check to see if the new switch fits into the controller at all:

The next step was to mark the right hole of the switch on the pcb and drill a mounting hole onto the pcb. A single screw is sufficient because the switch can not move anyways since the case of the controller prevents any further movement when the switch is pressed.

I then mounted the new switch on the pcb with an M2 screw. Also I bent the left connection pin so that it does not conflict with the case anymore (this is the Normally Closed pin which is not required anyway):

When I closed the controller case, I observed that the switch was always pressed and could not be released anymore. This was caused by a certain piece of the top case where the screws are mounted – this conflicted with the lever of the new switch and caused it to be always pressed. So I slightly adjusted that also by removing some of the plastic. Afterwards the controller could be reassembled and the switch fits perfectly inside the controller:

And, a final test shows that the switch is working properly 🙂