On 05/02/2004 David W.E. Roberts a wrote :
Hi,

this sander has started to mis-behave.

Instead of running smoothly (if a sander can be said to run smoothly) the
speed is variable and it sounds generally rough.

I have taken it apart and there seems to be no obvious visible problem, and
the brushes still seem to be of a reasonable length.

The speed variation gives the impression of 'misfiring' - it speeds up,
misses a bit, speeds up again.

1. Broken cable, most likely close to where the cable enters the
handle.

2. Faulty speed controller.

3. If there is a great deal of sparking on the commutator when the
problem occurs, check that the brushes are not sticking in their
holders. If they might be, rub the sides of the brushes down a little
on fine sand paper.

Run the unit held firmly in one spot, then try waggling the cable
about; operating the switch; thumping the sander.

--

Regards,
Harry (M1BYT) (Lap)
http://www.ukradioamateur.org