Agilent Technologies 54830 Series Service Manual page 97

Chapter 5: Troubleshooting
Power Supply Trouble Isolation
Figure 5-5
Power Supply Voltage Test Locations (A13)
Table 5-1 Power Supply Voltage Limits
Supply Voltage Specification
+5.1 V ± 0.1 V
-5.2 V ± 0.1 V
+12.2 V ± 0.3 V
-12.2 V ± 0.3 V
+3.3 V ± 0.1 V
Turn off the power and measure the power supply resistances to ground to check for
B
shorted supply lines.
You can probe the test points on A13, shown in Figure 5-5, for this resistance check.
Replace any shorted assembly.
C
You can locate the shorted assembly by disconnecting assemblies from the power supply, one at
a time.
Reconnect Assemblies and Cables
Reconnect all assemblies after testing. The oscilloscope must have all cables connected for correct power
up.
Override the Remote Inhibit signal.
4
Power up the by unit removing the W2 control cable from the fan controller board.
Replace the power supply.
E
1 If the +15 V bias is correct, but the oscilloscope will not power up with a 196-220Ω
2 Re-assemble the oscilloscope and apply power.
Check for the oscilloscope display onscreen.
F
1 You should see the oscilloscope display (see figure 5-2). If not, see the No Display Trouble
2 If you see the display, return to the Primary Trouble Isolation Flowchart.
5–12
resistor, replace the power supply. Chapter 6 explains how to remove and replace the
power supply.
Isolation Flowchart.
Limits
+5.0 V to +5.2 V
-5.1 V to -5.3 V
+11.9 V to +12.5 V
-11.9 V to -12.5 V
+3.2 V to + 3.4 V