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Testing the Power
Use this procedure to check the voltages produced by the power
SUPPlY
supply. The cardiograph must be connected to AC power to test all
the power supply voltages. All the voltage measurements are taken
with respect to ground. Refer to Figure 6-3 for voltage test point
locations.
Warning
9
When the cardiograph
is connected
to AC power, there are dangerous
voltages
on the line module terminals,
even when the AC switch is off.
When the AC switch is on, there are also dangerous
voltages
on the
terminals
of the mains transformer.
If you
must have
the AC power
connected
while the cardiograph
is open, do not touch any of the
exposed
connectors.
The rectifier
assembly
capacitors
store hazardous
amounts of energy
during AC and battery operation.
Be careful not to touch any of the
exposed
capacitor
connections.
1.
2.
Open the top cover assembly as described in Chapter 7,
"Removal and Replacement ."
Make sure the cardiograph is connected to AC and that the AC
switch is on. Then pull out the battery enough to disconnect it.
Caution
II
Be very careful to not short VIN to ground or to other pins. This
will result in cardiograph failure.
3. Measure VIN. It should read approximately 24 V DC. The
presence of this voltage confirms the proper operation of the
mains transformer and the rectifier assembly under light load.
4. Measure VBAT+.
It should read approximately 21 to 22 volts.
This voltage confrms the proper operation of the battery
charger.
5. Measure VBACK through the opening in the shield at the tab
on transistor Q5 (see Figure 6-3). It should read +5 V DC. Its
presence confirms the proper operation of the backup 5 volt
supply.
6-22
Troubleshooting
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Table of Contents
Troubleshooting
