Yamaha PORTATONE KB-280 Service Manual page 11

8. PNR Circuit Board
(Time required: About 6 minutes)
8-1 Remove the lower case assembly. (See procedure 1.)
8-2 Remove the MIDI circuit board. (See procedure 6.)
8-3 Remove the thirteen (13) screws marked [210J] and
six (6) screws marked [210K]. The PNR circuit board
can then be removed. (Fig. 10)
9. TWL, TWR Circuit Board and Speakers
(Tweeters)
(Time required: About 2 minutes each)
9-1 Remove the lower case assembly. (See procedure 1.)
9-2 Remove the TWL circuit board and TWR circuit
board in the following way.
9-2-1 TWL Circuit Board and Speaker L (Tweeter)
Remove the TW2 connector assembly and speaker
cable soldered to the TWL circuit board and remove
the two (2) screws marked [210L]. The TWL circuit
board and speaker L (tweeter) can then be removed.
(Fig. 5)
9-2-2 TWR Circuit Board and Speaker R (Tweeter)
Remove the TW3 connector assembly and speaker
cable soldered to the TWR circuit board and remove
the two (2) screws marked [210M]. The TWR circuit
board and speaker R (tweeter) can then be removed.
(Fig. 5)
10. Speaker Grilles L and R
(Time required: About 3 minutes each)
10-1 Remove the lower case assembly. (See procedure 1.)
<Top view (Lower Case Assembly)>
[200A]
Speaker L
(Woofer)
C1
[200B]
C2 B2 C3
[200B] [200B]
Keyboard assembly
[200A]: Bind Head Tapping Screw-B 4.0X10 MFZN2W3 (WE974500)
[200B]: Bind Head Tapping Screw-P 3.0X20 MFZN2W3 (WF492000)
[200C]: Bind Head Tapping Screw-P 3.0X20 MFZN2W3 (WF492000)
(Fig.12)
10-2 Set the eight (8) hooks [A] parallel to the groove in
the upper case assembly and remove the SP grille
L. (Fig. 1, 5)
* The speaker grille R can be removed in the same
manner.
11. PB Circuit Board and Wheel Assembly
(Time required: About 2 minutes)
11-1 Remove the lower case assembly. (See procedure 1.)
11-2 Remove the two (2) screws marked [210N] and
remove the PB circuit board with the wheel assembly
attached. (Fig. 10)
11-3 Pull out the wheel assembly from the PB circuit board.
(Fig. 11)
12. Speakers (Woofers) (Time required:
About 3 minutes each)
12-1 Remove the lower case assembly. (See procedure 1.)
12-2 Remove the four (4) each screws marked [200A] to
the right and left. The speakers (woofers) to the right
and left can then be removed. (Fig. 12)
PB
(Fig.11)
B3 C4 C5
[200B] [200B]
KB-280
Wheel assembly
[200A]
Speaker R
(Woofer)
C6
[200C]
11