PC 340 Palm Sander problem:

[Noel Hegan]

After 3 or 4 years of great service my PC 340 palm sander is behaving oddly. On start up all is well but after perhaps a minute the speed slows to about 50% (and obviously motor noise too). Any ideas? I've stripped it down and cleaned out most of the sanding dust as much as possible including any carbon build up on the armature. Brushes seem ok with plenty of material left and springs seem, well, springy enough.
Any ideas? A PC service is not an option (nearest is 2,000 miles away). Perhaps I've not managed to get to all the dust and I need to have another go at stripping and cleaning.
TIA,

Noel

[Bill Huber]

I am not a motor expert but I would say you have a winding problem and when it starts getting hot you start having the problem.

Is the switch getting hot when it starts to slow down, you my want to check that also, could be a bad switch.

You can buy a new winding for it or just about any other parts you need.

http://www.ereplacementparts.com/porter-cable-340-palm-grip-finishing-sander-parts-c-129_1997_3086.html

[Noel Hegan]

Thanks Bill, suppose it makes sense regarding the winding getting hot if that is indeed the cause. Haven't noticed the switch getting hot but I'll check and thanks for the link.