To Next Page

To Previous Page

pulse for the whole display frame (YD). The controller handshakes with the 80C188 using the READY line to

eliminate any lost data during display refreshes.

1.4 LED Board

The LED Board contains ve display banks and two display drivers. One of the display drivers controls the

patient temperature and air temperature display banks. The other driver controls the patient set temperature,

air set temperature, warmer bar graph, and the mode and override indicators.

This allows the two large displays (patient and air temperature) to be multiplexed at a slower rate than the

other LEDs. This results in brighter large displays. Each driver has a brightness potentiometer that is preset at

the factory and should not be adjusted in the eld.

1.5 Power Supply

The universal input switching power supply converts the line voltage to +5V DC and +12V DC. This supply can

source up to 75 watts. The 5 volts powers the electronics and the 12 volts is used by the EL display and for

future boards. Acceptable voltage ranges are 4.75V - 5.25V and 10.8V - 13.2V.

1.6 Peripheral Components

For the heater isolation transformer with relay board revision 9 or lower, the heater isolation transformer

isolates the incubator heaters from the mains voltage. The primaries mains input voltage comes from the relay

board and is switched by safety relay 1 and is also routed through the heater current sense circuit. The dual

primaries are connected in parallel for 115 volt operation and in series for 230 volt operation. The isolated

secondary output voltage is always 115 volts and goes directly to the solid state relays and the incubator

heaters

For the heater isolation transformer with relay board revision 10 or higher, the heater isolation transformer

isolates the incubator heaters from the mains voltage. The primaries mains input voltage comes from the relay

board and is switched by safety relay 1. The dual primaries are connected in parallel for 115 volt operation and

in series for 230 volt operation. The isolated secondary output voltage is always 115 volts and is input to the

relay board where it is used by the heater current sense circuit. It then outputs from the relay board to the solid

state relays and the incubator heaters

The humidier isolation transformer isolates the humidier heater from the mains voltage. The primaries

mains input comes from the relay board and is switched by safety relay 2. The dual primaries and secondaries

are connected in parallel for 115 volt operation and in series for 230 volt operation. The isolated secondaries

output voltage is equal to the mains input voltage..

Chapter 1: Functional Description

GE Giraffe Service Manual

Other manuals for GE Giraffe