The symptom pattern

The sanding drum isn’t spinning at the speed it used to, or the motor just sounds wrong — labouring, uneven, or different from how it normally runs. It’s the kind of fault that’s easy to put off until the sander stops altogether.

What’s actually happening

Triton’s own troubleshooting table gives this exact symptom four possible causes, in roughly the order worth checking them: the motor has simply overheated and needs to cool, the carbon brushes are worn, the drive belt has worn or stretched, or the motor itself has failed. The first two are things you can check and fix yourself; the last two, Triton’s own manual routes to a service centre rather than giving a DIY procedure for.

Working through it

If the sander had just been run hard, start with the simple option: switch off and let it sit for half an hour. Motor overheating is on Triton’s own list, and it resolves itself once the motor’s had time to cool — no disassembly needed.

If that doesn’t fix it, or the motor wasn’t hot to begin with, check for the specific signs Triton’s manual lists for worn brushes: a loss of power, intermittent running, or visible sparking where the brushes meet the motor housing. To get at them, stand the sander on its side, remove the screws securing the base cover, then take out the two screws on each brush cover to reach the brush assemblies. Replacing a worn brush means disconnecting its wire, swapping it, and reconnecting — straightforward with nothing more than a screwdriver. Triton are specific that both brushes get replaced together, even if only one shows wear, because mismatched brushes wear unevenly.

If the brushes are in good condition and the drum still isn’t reaching full speed, the drive belt is the documented next cause. Triton’s manual doesn’t give a belt-replacement procedure for this one — it routes a worn or stretched belt straight to an authorised service centre, and the same applies if the brushes and belt both check out clean, which points at the motor itself.

Verdict

Worth doing the free and cheap checks first — a cool-down costs nothing, and brush replacement is a genuine DIY job with Triton’s own step-by-step, a screwdriver, and an inexpensive pair of brushes. Once you’re past those two, though, don’t improvise a belt or motor repair: Triton’s own documentation sends both to a service centre rather than offering a home procedure, which is itself useful information — it tells you this isn’t a fault they expect an owner to open the motor housing for. Get a service quote before deciding whether it’s worth doing against the cost of a replacement sander.