Troubleshooting; Power Supply And Voltage Distribution; Processor Board Voltages - Dräger Narkomed 2B Service Manual

NM2B
3.0

TROUBLESHOOTING

This section contains information to assist the Draeger Medical, Inc. qualified
Technical Service Representative (TSR) in locating electrical faults affecting the
NARKOMED 2B monitoring and display devices. Since most troubleshooting efforts
begin with verifying power supply voltages, the following paragraph outlines the
voltage distribution scheme within the machine along with test points for each of the
voltages.
3.1

Power Supply and Voltage Distribution

In the NARKOMED 2B the power supply outputs at J10 are connected to J5
on the processor board for distribution. The CRTs are powered by 12 VDC; the
ventilator controller and the alarm channel are powered by 8 VDC. The
processor is powered by 5 VDC along with the other voltages. Under normal
load conditions these voltages are measured at the (+) end of capacitors C23,
C24 and C31 on the processor board. See Figure 3-1. The voltmeter return
should be connected to the (-) end of one of the capacitors. Table 3-1 lists the
acceptable range for each voltage.
TABLE 3-1: PROCESSOR BOARD VOLTAGES
The power supply voltages can also be measured in an unloaded condition.
CAUTION:
The test points are:
Rev. H
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LOCATION VOLTAGE
+ End of C23 + 5 VDC
+ End of C24 + 8 VDC
+ End of C31 + 12 VDC
Before disconnecting the output cable from J10 on the power
supply assembly, turn the System Power switch to STANDBY,
and disconnect the data cable from J9 on the power supply
assembly.
+5V:
+8V:
+12V: J10-5,-6
Com: J10-7,-8
3-1
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TROUBLESHOOTING GUIDE
ACCEPTABLE RANGE
4.85 to 5.15 VDC
7.45 to 8.47 VDC
11.52 to 12.24 VDC
J10-3,-4
J10-1,-2