Yamaha F30A, Service Manual

Page: 217 / 285

67C3K11
7-36
1
2
3
4
5
6
7
8
9
6. Remove the brush holder screws
B
,
brushes
C
, brush springs
D
, and oil seal
from the PTT motor base
9
.
Checking the PTT motor
1. Check the commutator. Clean with 600-
grit sandpaper and compressed air if
dirty.
2. Measure the commutator diameter.
Replace the armature if below specifica-
tion.
3. Measure the commutator undercut
a
.
Replace the armature if below specifica-
tion.
4. Check the armature for continuity.
Replace the armature if out of specifica-
tion.
5. Check the bearing. Replace the armature
if damaged.
PTT motor commutator standard
diameter: 16.5 mm (0.65 in)
Wear limit: 15.5 mm (0.61 in)
S67C7064
D
C
D
9
B
B
S6AU7066
S6AU7067
PTT motor commutator standard
undercut
a
: 1.00 mm (0.039 in)
Wear limit: 0.50 mm (0.020 in)
Armature continuity
Checking point Continuity
Commutator segments
b
Yes
Segment – Armature core
c
No
Segment – Armature shaft
d
No
S6AG7087
b
c
d
PTT motor