fiddle around with something ( also fiddle about with something British English ) phrasal verb ( see also ↑ fiddle )
1 . to move the parts of a machine in order to try to make it work or repair it:
I’ve been fiddling around with this old car for months but I still can’t get it to work.
2 . to make small unnecessary changes to something – used to show disapproval SYN mess around with :
Why did you let her fiddle about with the remote control?
The bus company is always fiddling around with the schedules.