Chainsaw Repair
Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Cordless Battery OPE - Corded Electric => Topic started by: mosis on July 26, 2012, 05:01:14 pm
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Hi, I bought an electric chainsaw about five years ago, a Performance Power Tools PWR1800CSD (the cheapest around at the time), to cut down a tree in my garden. I only used it for about five hours maybe, probably less than that, then put it up in my loft. Last week I got it out to see if I could cut away some more of the tree stump that I had left five years ago, but it wouldn't work.
I checked the fuse in the plug was okay, and dismantled the chainsaw to see if I could find out what was wrong. I am attaching some photos of the insides to help explain where I've got to. I have a handheld electric cable detector, which beeps when it is near a live cable, and by using this I was able to test that the switch was allowing power through to the cables going into the motor. The brushes are fine and are touching the motor (not sure what that part is called). There is a microswitch which turns off the chainsaw (I presume) when you bump the black buffer thing at the front, presumably this is to stop the chainsaw if it snags a branch and pulls it into the body of the chainsaw.
(http://img225.imageshack.us/img225/7320/chainsaw1.jpg)
(http://img812.imageshack.us/img812/8638/chainsaw2a.jpg)
(http://img339.imageshack.us/img339/4849/chainsaw3.jpg)
(http://img198.imageshack.us/img198/7353/chainsaw4.jpg)
(http://img204.imageshack.us/img204/1353/chainsaw5.jpg)
I read on another forum that there is (or can be) a capacitor that is attached to the motor, to stop arcing, and that it could have failed - is that likely? The inside of the chainsaw looked fairly clean, and it's only been used for less than five hours.
I don't quite understand what the coiled piece of metal on the drive shaft does. When I turned the motor by hand, to rotate the main shaft (not the motor shaft) in the direction that the chain would normally be turned, the end which connects to the chain didn't turn. When I turned it the other way, it did turn, but then the coiled piece of metal rotated anti-clockwise, and eventually reached the vertical metal bar that pushes down on it, and this is presumably not the way it normally turns, otherwise I imagine it would make a hell of a noise as it kept pushing past the vertical metal bar on every revolution (which is spring loaded to push downwards).
Many thanks in advance if anybody can help with fixing it, I don't want to throw it away and waste it if it's fixable.
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The thing that turns in the motor that the brushes ride on is called the armature.
The coiled spring on the output shaft is a overload device so that if there is too much load on the chain, the end of the spring next to the body will push on the micro switch and shut the power off to the motor.
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Welcome to the site and very neat labeled pics.
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Thanks for your replies, guys, I was thinking of connecting a battery across the plug terminals, then using a multimeter on the connectors to the brushes, holding the power switch on, and seeing if the current is getting through. If there is no current (presumably there won't be), do I need to do more dismantling? The worst I can do is find out that I can't put it all back together again. I was thinking that I would have to take out the motor to see if there is a capacitor wired into it. I read on other forums that the windings might be gone, but the chainsaw was working fine five years ago when I finished the job I was using it for.
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Most likely one of the safety switches are open and not making contact?
You can disconnect the brushes from the rest of the circuit and measure across them with a ohm meter to see if they are actually making contact with the amature.
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Probabley the first thing you need to do is take compressed air and blow all the crud out of it .
What you'll likely find out is with the push type quick connectors they use for electrical terminations is one has lost continiuity .Also those type trigger switchs aren't the best made for robustness .
On those switchs often times because they break both the hot wire and the neutral one side has burned out .If so bypassing the burned out side and just using the good side it should still work .They break both sides of the circuit on those double insulated type tools because the plug will fit in the receptical both ways often times .
It might be such a thing if it is the switch you could find a replacement because often times it's just a generic switch many use .