Electrical System Operation; Power Board And Power Supply Operation; Power Board Connector Assignments - Bosch ACS 561 Repair Instructions

ACS 561 Service Manual

Electrical System Operation

The electrical system provides the various volt-
age levels required for the machine to operate
effectively. The power board, power supply,
and control board work together to condition
the input voltage by removing voltage spikes
and noise, transforming the input voltage to
12VDC (power supply) for operating relays and
voltage regulators (power board), to power the
unit cooling fan, engage the compressor and
vacuum pump when required. Inputs from the
sensors and transducers are processed (control
board), to ultimately power the manifold sole-
noids (power board) for recovering, recycling,
and recharging vehicle A/C systems.

Power Board and Power Supply Operation

The Power Board is shown in Figure 3-1. The
Power Supply is shown in Figure 3-2. Refer to
these figures as needed.

Power Board Connector Assignments

See Figure 3-1, Power Board for connector
locations:
P1: Power Supply J2
P2: Control Board P19
P3: AC Input
P4: Power Supply J1
P5: Fan
P6: Vacuum Pump, Compressor
P7: High Pressure Switch
P8: Solenoids
The Power Board (PB) receives AC voltage at
PBP3 from the power switch through the circuit
P4
P3
P6
K2 K1
P5
Figure 3-1. Power Board
Robert Bosch GmbH
P8
J1
P7 P1
P2
47
Electrical
breaker to PBP3 pins:
• Pin 1 – Unit ground (on center divider)
• Pin 2 – AC low
• Pin 3 – AC high
The input voltage is immediately applied to the
Power Supply (PS) through PBP4 and the in-
terconnecting cable to PSJ1. The output of the
power supply is 12V ±0.1VDC. This is the main
system "control voltage" and used throughout
the unit for its various functions through PSJ2
to PBP1 and Control Board (CB) receives
12VDC from power board PBP2 through an
interconnecting cable to CBP19 (See Control
Board Functions). Relay K3 is used to couple
the 12V output from the power supply to the
power board through PBP10.
Input AC voltage within the power board is also
routed to relays K1, K2, K4, and K5. Relay
functions are:
• K1 – Compressor
• K2 – Vacuum Pump
• K3 – Fan
• K5 – UL Cutoff
Power for the unit fan, vacuum pump, and com-
pressor is routed to those units through PBP5
and PBP6 and wiring harnesses.
ss01319
J1
Figure 3-2. 12 VDC Power Supply
1
J2
6
V Adj.
SP00D00517 2018-07-11