Specifications

To test the hard disk drive voltages
Refer to chapter 6, "Replacing Assemblies," for instructions to remove or replace covers and
assemblies.
WARNING
This procedure is to be performed by service-trained personnel aware of the hazards
involved, such as fire and electrical shock.
Equipment Required
Equipment Critical Specification Recommended
Model/Part
Digitizing Oscilloscope > 100 MHz Bandwidth HP 54600A
1 Turn off the instrument, then remove the power cable. Remove the instrument cover
and the disk drive assembly.
2 Remove the hard disk drive from the disk drive assembly. Reconnect both hard disk
drive cables to the rear of the disk drive. Turn the disk drive over so that the solder
connections of the cable socket are accessible.
3 Connect the power cable, then turn on the instrument.
4 In the Sys PV menu select the Disk test. Select Run-Repetitive.
5 Check for the following voltages and signals using an oscilloscope.
Disk Drive Voltages
Pin No. Signal Voltage Pin No. Signal Voltage Pin No. Signal Voltage
1 RESET 27 IORDY 34 PDIAG
3 - 18 DATA 28 CABLE
SELECT
35 DAO
20 KEYPIN 29 DMACK 36 ADDR2
21 DMARQ 31 INTRQ 37 CS1FX
23 DIOW 32 IOCS16 38 CS3FX
25 DIOR 33 ADDR1 39 DASP
Pins 2, 19, 22, 24, 26, 30, 40 are GROUND
6 Select Stop, and turn off the logic analyzer. Remove the power cable.
Troubleshooting
To test the hard disk drive voltages
5–30