RWB II PLUS MICROPROCESSOR CONTROL
MAINTENANCE
S70-200 OM
Page 20
TROUBLESHOOTING THE RWB II PLUS
MICROPROCESSOR
This section contains information on troubleshooting and
making corrections to the microprocessor and control cir-
cuits of the RWB II PLUS unit. The section is composed of
four parts: a general information section, a troubleshooting
guide, a repair procedure guide, and a section with illustra-
tive schematics and data.
GENERAL INFORMATION
THE COMPONENTS WITHIN THE
MICROPROCESSOR CONSOLE
CAN BE INADVERTENTLY DAM-
AGED BY STATIC ELECTRICITY OR MISHANDLING.
ONLY QUALIFIED TECHNICIANS SHOULD DIRECTLY
HANDLE THESE COMPONENTS.
1. DO NOT REMOVE the microprocessor console cover or
attempt to make corrections to the microprocessor power
supply without shutting off the control power. Accidental
shorts can irreparably damage the SBC (single board com-
puter) or the display screens.
2. DO NOT HANDLE the SBC or the display screen boards
when their cables are disconnected without first attaching a
ground strap to prevent static electrical discharge from your
body.
Most problems encountered with the microprocessor and
control circuits will be the result of a wiring fault, blown fuse,
or failure of a peripheral control such as a solenoid coil or a
pressure transducer. Faults in the computer, while possible,
are unlikely. If a fault develops in the computer, the prob-
ability is that all functions will cease and the display screens
will go blank.
The control system of the RWB II PLUS compressor con-
sists of a 120 volt AC (high voltage) side and a 0-15 volt DC
(low voltage) side. The 120 volt side actuates solenoids,
relays, alarms, and other electromechanical functions. The
0-15 volt DC side operates the computer and its various
sensors. The microprocessor console contains the SBC
(single board computer) and two display screens.
When working within the micropro-
cessor console, 120 VOLTS CAN
CAUSE INJURY OR DEATH.
To troubleshoot the low voltage side of the RWB II PLUS
control circuits, it is necessary to have the following tools:
1. Accurate digital multimeter.*
2. Small wire stripper.
3. Small screwdriver.
4. Small snip nose pliers.
5. 15 watt soldering iron (no larger).
6. .032,60/40 rosin core solder.
7. IC chip extraction and insertion tools.*
8. Grounding strap.*
9. Static free grounded work surface.
* Available from Frick. Order kit 451862.
TROUBLESHOOTING FRICK SBC MICROPROCESSOR SYSTEM
(REFER TO WIRING DIAGRAMS)
SYMPTOM
PROBABLE CAUSES and CORRECTIONS
DISPLAYS ARE INOPERATIVE
Check the 10 amp fuse (2FU) which controls all voltage going to the
microprocessor.
Shut off power to the microprocessor. Remove the console cover and confirm
that all cable and wire connections are made.
OIL PUMP DOES NOT START
Verify that the Oil Pump HAND-OFF-AUTO switch (1SS) is in the AUTO
position and that the Emergency Stop Button is not depressed.
Output 11 controls the Oil Pump Starter Relay (3CR) when in the AUTO mode.
If HAND is selected on 1SS, Output 11 will not have any effect on the
operation of the oil pump starter.
If AUTO has been selected and the oil pump does not start, check for 120VAC
between Wires 39 and 2. If 120VAC is not found when the LED for Output 11
is on, check the fuse (FU11). If the problem persists, check the control
relay (3CR).
The Oil Pump Starter Auxiliary Contact switches voltage to Input 6 (Wires
28 and 2) when the auxiliary contacts are closed and the AUTO mode is
selected on 1SS. If the Input does not turn on and voltage is present at
Input 6, consult Frick Company.
