Dürkopp Adler 550-867 Operating Instruction page 59

Operation
Operating Instructions 550-867 - 00.0 - 11/2016
Cleaning the remaining thread monitor
WARNING
Risk of injury from moving, cutting and sharp
parts!
Crushing, cutting and punctures are possible.
Remove any lint from the area around the bobbin
case and the light barrier.
Do not clean the lenses of the light barriers unless
the machine is switched off.
Even the slightest remnants of fabric or yarn on the sensors of the
remaining thread monitor may cause the sensor to no longer
function properly. To ensure fault-free operation, the sensor of the
remaining thread monitor must be cleaned with compressed air
at least once a day ( p. 238).
To clean the remaining thread monitor:
1. Switch off the machine.
2. Clean the lenses of the light barriers using compressed air.
 You can now switch the machine back on.
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