Brother S-7300A-333P Instruction Manual page 82

10. CLEANING
71
2. Lubrication
Oil tank oil quantity
Check the oil gauge window (1), and add more oil if the oil
gauge (2) is below the lower reference line. (Refer to "3-3.
Lubrication".)
Upper reference
line
Lower reference
line
0907D
3. Checking
1. Replace the needle if it is bent or if the tip is broken.
2. Check that the upper threads have been threaded
correctly.
(Refer to "4-5. Threading the upper thread".)
3. Carry out a test sewing.
0908D
S-7300A