Probably either the intermittent sparking or the spring tension or length of
the brush. Normally though if you let them go too far the comutator starts
to get eroded away, so best to swap them. In old vacuums they had a similar
thing, but you don't see it these days, probably cos they are chuck it away
and by a new one merchants.
Brian
--
--
From the sofa of Brian Gaff -
Blind user, so no pictures please!
Today is Yesterdays Tomorrow.
"Harry Bloomfield" wrote in message
...
Steve Walker formulated on Friday :
A quick google brings up the manual and the red LED is warning of "Carbon
Brush Wear."
Thanks, I wonder how they measure that? I have opened it up, to dust it
out and the brushes look fine..