Solenoid Drive Board - Wayne Dresser Vista 1 Series Service Manual

3.2. LIGHTED CASH/CREDIT INTERFACE BOARD, continued
Located on this board is a fuse which fuses the AC input to the select board. If this fuse
should open, the push to start or cash/credit select switches will go blank; and the push to
start (or cash/credit or grade select) and function switches will not work. If the dispenser
requires that a push to start, cash/credit or a grade select switch be pressed it will not reset.
Once the select switch has been pressed the push-to-start signal must be received at the
push-to-start input connector J5 at nozzle on, if Pin 1 and Pin 2 are both open either must
be grounded and opened again for the dispenser to operate.
This board usually comes with a fixed address, however, it contains provisions to add a four
position DIP switch which must be set correctly in order for the display to operate.
Position 1
Position 2
Position 3
Position 4
3.3.

SOLENOID DRIVE BOARD

The solenoid drive board primarily serves as an AC switching board. By utilizing solid state
relays, it controls AC power to the pump motor relays, and (in non-blenders) the two stage
actuator valves. Also, the solenoid drive board enables the correct pulser assembly by
switching the pulser select lines. In addition (in blenders), the blender solenoid drive board
provides DC pulse modulated signals to operated the proportional flow control valves.
Located on the solenoid drive board is a fuse (F1). This fuse controls all AC voltage
supplied to the solenoid drive board. If the fuse opens the dispenser will reset, but the AC
valves and relays will not be energized.
Blender solenoid drive boards have two additional protection devices: PF1 and PF2. These
are poly fuses that supply 24VDC power to the proportional flow control valves for side 1
and side 2, respectively. If one of the valve lines is overloaded, the poly fuse will open.
When the overload is removed, the poly fuse will close, and the circuit will reset and return
to normal operation. Blender solenoid drive boards contain a micro-processor and two
additional troubleshooting aids: two LEDs that indicate the state of communications to the
computer and to the valves. The LED labeled DS1 is the "Valve Enable" indicator and will
light steadily as soon as a grade is selected upon nozzle removal. This indicates that the
computer base Pump processor has enabled one or more valves on either side of the
dispenser. The other LED labeled DS2 is the activity indicator for the solenoid drive board
(SDB) micro-processor and will blink about every 2 seconds to indicate that, the processor
is functioning properly, and that communications have been established between the sole-
noid drive board processor and the computer base Pump processor. At power up, this lamp
will blink at a faster rate, and then pause, until the communications are established. A
steady On or a steady Off indicates that the SDB processor is not functioning properly.
14
Part No. 920160 Rev A
Open or off
Closed or on
Open or off
Closed or off
February 1997