28
307–758
CIRCUIT BOARD REPLACEMENT
WARNING
To reduce the risk of serious injury, follow the illus-
trated Pressure Relief Procedure warning on
page 24 whenever you are instructed to relieve
pressure.
NOTE: Read the GENERAL REPAIR INFORMATION
on page 24 before doing this procedure.
NOTE: Refer to Fig 28–1 and 28–2 for this procedure.
1.
Relieve pressure.
2.
Remove the pressure control cover.
3.
Turn the pressure control knob to the minimum set-
ting to release spring tension on the board. Check to
be sure only three or four threads of the pressure
control knob shaft are exposed below the pressure
adjustment nut (S). Loosen the nut, if necessary.
CAUTION
Step 2 is essential to reduce the risk of damaging
the circuit board while removing or installing it.
4.
Disconnect all seven wires from the board. Pay close
attention to where connections are made.
5. Pull out the plastic-tipped pin (330). Push the bottom
of the circuit board (72) toward the wall of the pres-
sure control and carefully slide the board out.
6.
Reinstall the new board in the pressure control at the
same angle as it was removed.
7.
Reconnect all wires. Ease the pin (330) into the re-
tainer.
8.
Perform the PRESSURE CONTROL ADJUST-
MENT, page 30, if you installed a new board.
PRESSURE
CONTROL KNOB
330
S
Fig 28–1
01230
ÉÉ
ÉÉ
ÇÇÇ
ÇÇÇ
É
É
ÉÉ
ÉÉ
72
Fig 28–2
330
72
AC1
AC2
G1
G2
_
+
WHITE
BLUE
YELLOW
RED
GREEN
BLACK
WHITE
GROUND
WIRE
BLACK
POWER SUPPLY CORD
THERMAL SWITCH
MOTOR
MOTOR
LEADS