Background
A neighbour of my Mothers told me that her hedge trimmer was behaving erratically and producingsmoke during operation and also sometimes when she had let go of the trigger it continued to produce smoke. Often if she depressed the lever to start the trimmer, the motor would hum and then burst into life and the smoke would go away.
I said i would have a look at it to see if it could be rescued from the recycling yard. As with so many of these types of devices these days, the hedge trimmer was a generic model made in the Far East with a western brand name stamped on it.
I said i would have a look at it to see if it could be rescued from the recycling yard. As with so many of these types of devices these days, the hedge trimmer was a generic model made in the Far East with a western brand name stamped on it.
![Picture](/uploads/2/1/2/7/21271896/editor/dscf4242.jpg?1643671638)
The first job was to remove the screws from the case and open up its two halves.
While the case was open i removed all the hedge debris, leaves, twigs etc that had got into the case over the years,
![Picture](/uploads/2/1/2/7/21271896/editor/dscf4243.jpg?1643671657)
My first thought when my neighbour reported smoke coming from the case was that the brushes were damaged or worn out.
I ordered replacement ones on line and they arrived a few days later
This picture shows the two old brushes with one of the new ones in between them.
They show quite a bit of use and although they still have quite a bit of life in them i decided to go ahead and replace them anyway.
I ordered replacement ones on line and they arrived a few days later
This picture shows the two old brushes with one of the new ones in between them.
They show quite a bit of use and although they still have quite a bit of life in them i decided to go ahead and replace them anyway.
![Picture](/uploads/2/1/2/7/21271896/editor/dscf4245.jpg?1643671740)
While examining the internal components of the trimmer case i noticed that there seemed to be some distortion to the case of one of the microswitches
I removed it from its mounting and popped open the case which in the majority of microswitches of this type is quite easy.
This revealed that the contacts were badly damaged due to heating and arcing. The spring return mechanism was no longer working reliably so i decided to replace the microswitch as well.
![Picture](/uploads/2/1/2/7/21271896/published/dscf4248.jpg?1643671804)
I just happened that i had a suitable replacement lying around. This was part of a couple of microswitches purchased at Browns Radio(Now long closed) in Edinburgh around 1991/1992 to repair a faulty one on a dishwasher door.
The date code indicates this one was made in the first few weeks of 1990!
I had to cut down the electrical contacts to fit the case as they were slightly longer than the originals and then i soldered the microswitch in place.
![Picture](/uploads/2/1/2/7/21271896/editor/dscf4249.jpg?1643671972)
This picture shows a close up of the new microswitch installed and the rest of the case ready to be re-assembled.
![Picture](/uploads/2/1/2/7/21271896/published/dscf4250.jpg?1643671924)
Here the internal components have all been re-assembled in the case ensuring that the wires are carefully routed and will not snag or get crushed when the case is closed up.
Care was taken to ensure that the safety interlocking mechanism was properly installed and working correctly.
After completing the repairs and re-assembling the trimmer case the blades were oiled and the hedge trimmer was tested in a few hedges unrgently requiring cutting. The test was successful and the hedge cutter is now happily trimming hedges arounfd my mothers neighbours garden. For the cost of a set of motor brushes and a new microswitch, another perfectly serviceable tool has been saved form the recycling yard!