It is supposed to be self extracting, meaning that if you turn the nut far enough, the bit will pop up; no need to remove the nut. If the bit is stuck, try to pull it out with pliers. You may even need penetrating oil. Probably just rust; there is not much that go wrong. Good luck. I’m happy to assist further over the phone at https://www.6ya.com/expert/bill_f6ca18ca1db028ed
it is not tension you adjust but parallel running of the front pulley
normally there is a knob along the arm that you can move in or out carefully and you will see the belt run back to covering the pulley
best do it when you spin the belt by hand as the adjustment is touchy
The return bumper under the hammer in mine deteriorated. This keeps the hammer from resetting to the correct height and does not let the trigger engage. I am looking for a peice of rubber to see if that will work.
lock the collet by turning the on-off switch to off, push the button under the on-off switch to lock the collet then use the supplied wrench to loosen the collet.
