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Symptom Possible Cause Action

Humidier

reservoir has

scaling.

Use of tap water Replace humidier reservoir.

4.6 Additional Troubleshooting Tips

Following are tips on taking many of the measurements and diagnosing the failures that are referred to in the

troubleshooting charts. For some tips, it may be necessary to determine the revision level of the relay board.

The revision code is located in a triangle printed on the component side of the PCB. Refer to Figure 6-34 and

Figure 6-35.

4.6.1 Raising and Lowering the Elevating Base

In the event of a system failure, it may be possible to raise or lower the elevating base in the service mode. Hold

down the override button (>37) to bring up the service screen. The pedals are now activated and may assist in

troubleshooting or transport.

If the switches still do not operate it may be possible to raise or lower the elevating base using the pedal

function on page 2 of the service screen.

4.6.2 Incubator Heaters and Bed Safety Thermostat

There are two 115 volt incubator heaters rated at 225 watts at 104 volts and mounted at opposite ends of

the incubator heat sink. They are always connected in parallel and are powered by isolated 115 volts from the

heater isolation transformer. This voltage is switched by the incubator SSR.

The resistance of each heater is about 48 ohms and they are in parallel so you should measure about 24 ohms.

Note that the bed safety thermostat is in series with the heaters so if the reading is open circuit you must take

readings at the connectors under the bed to determine which is defective.

To measure the incubator heater resistance on units with revision 9 or lower relay boards, disconnect the black

wire on the incubator SSR and the white wire on the output of the isolation transformer and measure between

these 2 wires.

To measure the incubator heater resistance on units with revision 10 or higher relay boards, disconnect the

black wire on the incubator SSR and the connector from J54 on the relay board. Measure between harness

connector pin 4 and the black wire.

The incubator heater and bed safety thermostat resistance can also be measured by the removing the bottom

cover and measuring directly at the components.

Chapter 4: Troubleshooting

GE Giraffe Service Manual

Other manuals for GE Giraffe