Hedge trimmer?

Black & Decker GT 6060(2.5 yrs old used three times a year) checked for any lose connections found none. Halfway through cutting hedge stopped working. Checked power switch its fine.
Reassembled started for 30 secs full speed slowed then stopped.
Lightly tapped blade end on footpath it started again full to slow then stopped. Would this indicate one brush sticking ?
Motor brushes don't look easy to work on.
Have tapped it several times with same result.
Many thanks
Estimated repair by equipment repairer £45-£60. It only cost £55 so if cant fix myself it looks like new one with longer warranty
.