Brother BAS-311H Service Manual page 147

Error status #18 The machine cannot produce correct stitches.
Probable causes
1. Malfunction of synchronizer
2. If uneven seams are being sewn,
there is a malfunction of the pulse
motor or the mechanism is
incorrectly adjusted.
Check/repair/adjust
Refer to step 1 in #17.
a. Refer to step 4 in #6.
b. If the uneven seams are due to insufficient
work clamp pressure, adjust while referring
to "8-17. Adjusting the work clamp lift
amount".
c. If there is play in the feed mechanism,
adjust the feed mechanism.
BAS-311H
10. ELECTRIC MECHANISM
Parts to be replaced
138