Fujitsu MBB2073RC, MBB2147RC manual Troubleshooting, System-level field troubleshooting

			6.4 Troubleshooting
	Table 6.2		System-level field troubleshooting
Item			Recommended work
DC power level		Check that the DC voltage is within the specified range (±5%).
		For +5V DC, measure the voltage between pin 20 (+5V) of the interface
		connector and the nearest PCBA mounting screw (GND) from the
		interface connector, and confirm the value is from 4.75 to 5.25 VDC.
		For +12V DC, measure the voltage between pin 2 (+12V) of the
		interface connector and the nearest PCBA mounting screw (GND) from
		the interface connector, and confirm the value is from 11.4 to 12.6 VDC.
Electrical noise		Make sure the maximum ripple peak-to-peak value of +5V DC is within
		250 mV and +12V DC is within 250 mV.
		Make sure the high frequency noise (over 20 MHz) is less than
		100 mVp-p.
System cables		Check that all system cables are connected correctly.
System diagnostic test		When possible, execute the system level diagnostic routine as explained
		in the host computer manual. This gives a detailed report of a possible
		fault.
Intermittent or nonfatal errors		Check the AC voltage from the power supply. Check the DC voltage
		level at the power connector for the HDD.
		If the AC voltage level is abnormal or there is a lot of electrical noise,
		notify the user of the error.
		If the DC voltage level is unstable, replace the power supply unit.
		If possible, replace the HDD. If replacing the HDD does not eliminate
		the error, the removed HDD is probably not faulty. To continue error
		analysis, refer to the hardware and software manuals supplied with the
		system.

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