Before you spend a lot of effort try for a new part. Such things are usually cheap! John Ferrell W8CCW "My Competition is not my enemy" http://DixieNC.US ----- Original Message ----- From: "Gordon Williams" To: "pic microcontroller discussion list" Sent: Tuesday, March 06, 2007 12:25 PM Subject: [EE] Cordless Drill Speed Control problem > Hi, > > I have a Ryobi cordless drill where the speed control has gone but it > still > works at full speed. I was wondering if anyone has taken something > similar > apart and could point me in the right direction. I've searched the web > but > come up blank. > > This drill has is about 8 years old but has only seen occasional work. > When > using it yesterday I found that I could no longer control the speed. It > was > either all or nothing. When I slowly squeeze the trigger I can barely > hear > a very high pitch noise (as I usually hear with slow speed operation) but > with no movement from the motor and using my hand I can easily turn the > motor in both directions. As I squeeze a bit more the drill turns on full > speed. > > I was wondering if there was a secondary switch in the trigger that would > by-pass the PWM and FET system and connect the battery directly to the > motor. The high pitched noise I am assuming is the PWM. > > Any ideas on how these things work? > > Regards, > > Gordon Williams > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist