Coffee machine woes

[Dr Jekyll]

I've had a Smarter coffee machine for a few months, only using it occasionally and I recently noticed the coffee wasn't tasting quite right. I decided it was about time I cleaned the filter, but since doing so the coffee is ridiculously weak, almost clear water.
One possibility is that the grinder failed previously but the sludge in the filter was adding a bit of strength to the coffee, this would explain why the bean level went down so slowly for the last few cups. But it does make a grinding noise and the beans move around in the container so it's doing something. Any suggestions? I'm wondering about descaling, if the grinder is the issue, or trying filter coffee instead of beans to see if that makes a difference.