HP 330 Service Information Manual page 170

Inoperative Unit Procedure
An Inoperative Unit is one which does not appear to function at all. No power-on or self-test
LEDs, fan rotation, or response to keyboard inputs are typical symptoms. Nearly all inoperative
units have one of these basic problems:
• Defective power supply.
• Voltage select switch in wrong position
• Improper line voltage/frequency or defective power cord.
Follow this procedure to isolate the problem. If an assembly is defective, this procedure indicates
which assembly should be replaced to eliminate the problem.
WARNING
Hazardous voltages are present in the unit when it is plugged in. Thrn
the unit off and unplug the unit before placing test leads, checking
fuses, or removing/installing assemblies.
1. Check that the voltage select switch is set correctly. Refer to Chapter 2 in the Service
Handbook for the correct procedures.
2. Check that the fuse is good and of the correct size. If the fuse is defective, replace it. If
the fuse is good, skip to Step 4.
3. Turn the unit on, then turn it off and recheck the fuse. If the fuse is defective skip to
Step 5, otherwise go on to Step 4.
4. If one or both fans are not rotating, check the voltage across the inoperative fan's voltage
terminals. If the voltage is correct, the fan is defective. If not, continue with the voltage
check procedure. Fan voltage should be as shown below.
a. Large fan voltage:
+
12 V dc.
b. Small fan voltage: + 17 V dc (+5 and -12 V dc).
5. If the fuse is open, one of the installed assemblies is defective.
6. Remove all assemblies from the slots.
7. Replace the fuse. Install the power cord and turn the unit on, then turn it off and recheck
the fuse. If the fuse is good, one of the removed assemblies is defective. If the fuse is
open, the power supply, motherboard, or backplane is defective; go to Step 8.
8. Disconnect the card cage ribbon cables.. After installing a new fuse turn the unit on,
then off, and check the fuse. If the fuse is good, the backplane is defective, If the fuse is
blown, the power supply or motherboard is defective.
9. Repeat Step 8 but instead remove the motherboard. If the fuse is good, the motherboard
is defective. Otherwise, the power supply is defective. After replacing the defective unit,
you should now be able to perform Live Unit Troubleshooting Procedures.
154
Troubleshooting