BCI Advisor, Service Manual

Chapter 3: Block Level Description

3-2 

          Advisor

®

 Service Manual

Universal AC to DC Power Supply Assembly

WARnInG!   Shock Hazard. This circuit board assembly operates at AC mains potential and is energized 

whenever the power cord is plugged into the mains supply, regardless if the Advisor® is on 

or in the STAnDBY/oFF mode. never service this equipment while AC power is connected to 

the monitor. Be sure to reattach the protective earth wire (green with a yellow stripe) to the 

power supply chassis after servicing.

The Universal AC to DC Power Supply is a medical grade power supply. It accepts AC mains (at TB1) from the AC 

Power Entry Board and o12 VDC (TB2) to either the DC Power Interconnect Board or the Battery Charger 

Board when the rechargeable backup battery option is installed. The universal aspect allows operation from 100 

to 240 VAC mains at either 50 or 60 Hertz. This assembly provides the main +12VDC power distribution within 

the Advisor. This assembly is considered a critical component; meaning it must be replaced by identically the 

same power supply.

DC Power Interconnect Board

The DC Power Interconnect Board contains two connectors which route DC power from the universal AC to DC 

power supply (J1) (rear chassis half) to the Main Board (J2) (front chassis half). When the rechargeable battery 

backup option is installed, the DC Power Interconnect Board is replaced by the Battery Charger Board.

Battery Charger Board (Rechargeable Battery option)

The Battery Charger Board controls the routing of power to the Main Board when the rechargeable battery 

option is present. When powered from the AC mains, the universal AC to DC power supply powers the Main 

Board. When AC mains voltage is not present, the rechargeable backup battery powers the Main Board. In 

either case, this board is powered whenever the AC mains voltage is connected and/or the backup battery 

is present (D2 and U1), regardless if the Advisor is on or in the standby/off mode. The battery charger micro 

controller, (U6), monitors both the presence of AC power (via voltage detector U7) and the charge status or 

presence of the rechargeable battery (connected at J4). It then determines which source will be used to power 

the Main Board. When AC mains is present, the battery charger micro controller powers the Main Board from 

the output of the universal AC to DC power supply (via mosfet Q6) and disconnects the battery (via Q7). It 

also controls the charging of the rechargeable battery when needed (via U2). When AC power is disrupted the 

battery charger micro controller automatically switches over to the rechargeable backup battery (via mosfet 

Q7) for uninterrupted operation. The Battery Charger Board supports a Nickel-Metal-Hydride (NiMH) battery 

chemistry. Battery short circuit / overload conditions are protected by way of the self-resetting fuse F1 which 

will remain open circuited as long as the short circuit / overload condition persists. Mosfet Q8 provides reverse 

battery protection. The micro controller reports battery status to the Main Board and controls the front-panel 

BATTERY LED by way of J5. When AC mains is disconnected, this LED will remain off. When AC mains is present, 

the BATTERY LED blinks when charging the battery and remains constantly on when the rechargeable battery is 

fully charged. The Battery Charger Board also controls the AC LED by way of J5. If AC power is not detected then 

the Battery Charger Board will turn off the AC LED by turning Q2 on. If AC power is detected then the Battery 

Charger Board will turn on the AC LED by turning Q2 off.

Spo

2

 (Pulse oximetry) Board

SpO

2

 (Pulse Oximetry) Board is connected to the patient-isolation side of the Main Board which provides isolated 

power and isolated bi-directional TTL serial communications directly to the ARM7 microprocessor. The SpO

2

Board provides a header connector for the cable harness to the SpO

2

 probe connector mounted on the side of 

the Advisor. The Board also provides a ribbon cable connector for connection to the patient-isolation side of the 

Main Board (J14). Several versions of SpO

2

 boards are compatible with the Advisor. Each are uniquely identified 

at power-up and reported on the power-up screen as well in the “SOFTWARE VERSION” menu.