Generic advice: Replace carbon brushes. Exclusive manual fix: Yes, but the manual specifies that the KL 1206 uses two different brush sizes (left and right). The left brush (motor side) is 8mm x 6mm x 15mm; the right brush (switch side) is 8mm x 6mm x 12mm. Installing two identical brushes causes uneven commutator wear. Order brush set Bosch #2609256005.
Once you secure the bosch kl 1206 manual exclusive, here is how to read it like a pro.
Open the blade access cover. You will see a small steel roller. The exclusive manual states: “The roller should just kiss the back of the blade—no more than 0.1mm gap.” Too much gap causes blade wander; too tight causes overheating. Use a feeler gauge (0.004 inches) to set this.