STEP 1: CLEANING AND OILING. Remove the upper thread, bottom bobbin or shuttle and needle. With the presser foot up, try to run the machine at full speed for one minute. If you hear a noticeable variation of the speed, your machine may need some oil. If you still have the manual then follow it. If not, proceed like this: try to remove the top cover if your machine has one. If not, you should be able to find holes on top of it.
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