Brother GT-3 Series Service Manual page 313

6. Replacing Parts
4)
Remove those remained ink (c) and the double-sided adhesive tape (d) as shown in the photo
E with the Clean Stick (e) with Maintenance Solution applied (see photo F) to make them clean
as shown in the photo G.
(d)
9.
Mount the Needle Bracket on the Cartridge Base, with clean Needles on.
Confirm the screwing order of the three Screws:
1)
Fix the Screw (13) Temporarily.
2)
Tighten the Screw (14).
3)
Tighten the Screw (13).
4)
Tighten the Screw (15) in the center.
(13)
10. Mount the two Tube Holder Fix (2) and the two Clamps, NK-18N in the reverse process of the step 4-5.
<Note>

The recent productions have neither those Screws nor Clamps, NK-18N mounted.

Pay very much attention to the Tubes in the position (f) as shown in the photos below.
304
(c)
(e)
E
(13)
(f)
F
(14)
(15)
GT-3 Series
G
(f)