Control Board Operation; Control Board Connector Assignments; Control Board Functions - Bosch ACS 653 Repair Instruction

Electrical

Control Board Operation

The Control Board, Figure 3-3, is mounted in
the control panel and provides the control for
the entire operation of the unit based upon the
signals from sensors, transducers, and manual
operator inputs via the keyboard.

Control Board Connector Assignments

See Figure 3-3 for connector locations.
J1: Power Board J1
J5: USB Port
J6: Refrigerant Identifier (if present)
P1: Air Flow Sensor (for ACS 663 only)
P2: Oil Drain Load Cell
P6: Accumulator Pressure Transducer,
Low-Side Pressure Transducer, ISV Tank
Pressure Transducer and ISV Tank Temperature
Sensor.
P8: Scale Assembly
P13: USB Port
P15: Printer Power (if present)
P17: Keypad
P18: Printer Data (if present)
P19: 12 VDC from Power Board P2
The Control Board (CB) receives power from
the Power Board PBP2 to CBP19. This voltage
is used to power the sensor circuits, processors,
and is provided as an output signal to the Power
Board to energize manifold solenoids, and the
compressor and vacuum pump relays.
Three regulated power supplies of 8 VDC,
5 VDC, and 3.3 VDC provide the power for the
logic and data circuitry. A fourth regulated power
source supplies voltage to the optional printer.
P17
P12
P13
P1
P3 P2 P9 P10
Figure 3-3. Control Board
SP00D00624 2021-04-08
J8
P7 P11
J2
J3
J7
J1
P8
ACS 653, ACS 663 Service Manual

Control Board Functions

1. Reads Keypad
• If a key does not respond, it's most likely
that:
1. it isn't supposed to respond at that
time
2. the keypad is faulty (replace keypad)
3. Operates Display
• The display contrast changes with
temperature and light conditions.
• Always try to adjust the contrast before
replacing the control board (Up/Down
Arrows).
• After adjustment, if there are missing
seg ments, characters, etc., in the lines
of the display, replacement is required.
4. Contains Programming
• Normally, if a unit runs at all, the program
and the control board are okay. Reflashing
does nothing unless a valid upgrade
program is available.
5. Communicates with USB ports.
• This occurs during software updates.
6. Contains calibration and other stored
variables
• Normally if a variable is corrupt an error
will appear.
• Never replace the control board to try to
correct a reading inaccuracy.
• If the calibration data is repeatedly
corrupt and causing calibration errors or
won't hold calibration, the board could
be suspect.
7. Communicates with the Power Board
• Never replace the control board to correct
an input reading or output failure.
• If any part of the program works the
controller is not the problem (it will not
fail to operate any one output or input).
68
Robert Bosch GmbH