Loud bang from AEG Favorit 445

I have an AEG Favorit 445 dishwasher, it’s about 14 years old but not heavily used. A couple of weeks ago the 15A fuse in the wall conection unit blew (presumably at switch on, as the machine had finished the previous wash OK).
I replaced the fuse and the machine runs, but now, at seemingly random intervals during the cycle there’s a very loud bang. I can’t tell if it’s mechanical or electrical, but it doesn’t sound like water hammer and there’s no smell of burning. It does not happen every wash, but on the last run it happened four times. Also, (possibly not related and maybe even my imagination) the pump/motor which runs during the cycle sounds a bit rougher than it used to.
Apart from the noises the machine works OK, although I noticed some sludge on some of the cutlery in the last wash.

Any suggestions what could be wrong?
Thanks.