Abstract: The invention relates to a portable handheld work apparatus such as a cutoff machine, motor-driven chain saw, brushcutter, blower apparatus or the like. The apparatus includes a drive motor (2) for driving a work tool (6) and is provided with a security circuit (20). The security circuit (20) switches the drive motor (2) of the work apparatus into an operational-ready state or into an out-of-service state in dependence upon received signals of a receiver unit (18). The receiver unit is configured to receive at least one operating code. The receiver unit (18) is configured for receiving a service code (27) and, with the receipt of a service code, switches the drive motor into only a temporary service state.

Abstract: In a method for operating a power tool with a diagnostic device, wherein the power tool has an internal combustion engine, a generator as an energy supply, and an electronic control unit, wherein a diagnostic device is connectable to the electronic control unit, and wherein the electronic control unit has an operating mode and a diagnostic mode, a non-uniform voltage signal is supplied by the generator as an energy supply and a uniform voltage signal is supplied by the diagnostic device as an energy supply. The electronic control unit evaluates the voltage signal that is being supplied as an energy supply and switches to diagnostic mode when the voltage signal is the uniform voltage signal supplied by the diagnostic device.

Abstract: A hand-held working apparatus has an internal combustion engine having a crankshaft which is driven in rotation. The crankshaft drives at least one tool of the working apparatus via a centrifugal clutch. The working apparatus has a device for determining the speed of the internal combustion engine and a control device which controls the internal combustion engine. It is provided that the profile of the speed of the internal combustion engine is evaluated by the control device, and that the engagement speed of the centrifugal clutch is determined from the profile of the speed of the internal combustion engine. A method of operation is also provided.

Abstract: A handheld work apparatus has a combustion engine with an ignition unit, a unit for supplying fuel and a device to determine the rotational speed (n). The ignition unit includes a spark plug, a coil and a pole group. The pole group and the coil are moved in dependence on the rotational movement of a crankshaft of the combustion engine, whereby a ignition voltage is induced in the coil. The work apparatus has an open loop control which controls the ignition time (ZZP). A diagnostic unit for damage diagnosis is detachably connected to the work apparatus. For damage diagnosis, the diagnostic unit captures the course of the induced ignition voltage over at least one engine cycle when the combustion engine is running and damage is determined on the basis of the course of the captured voltage.

Abstract: The invention relates to a portable handheld work apparatus such as a cutoff machine, motor-driven chain saw, brushcutter, blower apparatus or the like. The apparatus includes a drive motor (2) for driving a work tool (6) and is provided with a security circuit (20). The security circuit (20) switches the drive motor (2) of the work apparatus into an operational-ready state or into an out-of-service state in dependence upon received signals of a receiver unit (18). The receiver unit is configured to receive at least one operating code. The receiver unit (18) is configured for receiving a service code (27) and, with the receipt of a service code, switches the drive motor into only a temporary service state.

Abstract: In a method for operating a power tool with a diagnostic device, wherein the power tool has an internal combustion engine, a generator as an energy supply, and an electronic control unit, wherein a diagnostic device is connectable to the electronic control unit, and wherein the electronic control unit has an operating mode and a diagnostic mode, a non-uniform voltage signal is supplied by the generator as an energy supply and a uniform voltage signal is supplied by the diagnostic device as an energy supply. The electronic control unit evaluates the voltage signal that is being supplied as an energy supply and switches to diagnostic mode when the voltage signal is the uniform voltage signal supplied by the diagnostic device.