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2.1.2 Precautions on handling Microdrives
Main causes of failures in hard disks including Microdrives are
listed as follows.
(1) Failures caused by shocks
(2) Failures caused by static electricity
(3) Failures caused by power cut during the operation
2.1.2.1
Failures caused by shock
One of the causes of the Microdrive failures is a crash between
the disk and the head caused by falls or shocks. The results of
the crash are listed as follows.
• The scratch on the surface of the disk (crash scar) disables
reading/ writing of the damaged part.
• The magnetic material that came off by the crash (disk frag-
ment) causes head reading failure.
• The head distortion deteriorates the read/ write attribute.
• The change in the space between the head and the disk dis-
ables the normal read/ write.
Stronger shocks result in the motor axis distortion, causing axial
runout and deterioration in performance such as disabling the
trace of normally recorded signal.
Pay extra caution not to drop or give shocks to the Microdrive
while servicing, and make sure to store the Microdrive in a pro-
vided plastic case.
Head
Disk
Disk
Head floating height
2500
2000
1500
1000
500
0
(G):Gravity
Operation
200
Microdrive
200
2.5 inch HDD
3.5 inch HDD
Disk
fragment
Crash
between
the head
Crash scar
and the
disk
on the disk
Operation
Excessive
power is
Disk
Performance
generated
shift
in the
deterioration
mechanism
Operation/ Non-operation
1-6 (No.YF058)
Head
Crash scar
Disk fragment
0.03um
Non-operation
2000
2000
55
300
(G):Gravity
Shocks(G)
50
100
150
200
250
300
Read
Read error
Normal
error
Shocks(G)
1400 1600 1800 2000 2200 2400 2600
Performance
Normal
deterioration
Model:HMS360404D5CF00SERIES
NOTE:
The shock of 200G(G:Gravity), a maximum impact value in
operation, is equivalent of the impact of dropping from 20-
30cm above the hard floor. The shock of 2000G, a maximum
impact value in non-operation, is equivalent of the impact of
dropping from 75 - 100cm above the hard floor.
2.1.2.2
Failures caused by static electricity
Microdrives are designed to tolerate static electricity up to 15kV
approx. However, head destruction or boot failure will occur as a
result of high static electricity given to the magnetic head of a Mi-
crodrive that is very vulnerable to static electricity.
As same as handling other electronic parts, make sure not to
take charge of static electricity before touching a Microdrive for
checking or repairing.
In addition, make sure to store the Microdrive in a provided plas-
tic case when it is not in use.
The voltage of 15kV has enough power to break Microdrives de-
stroying heads etc. Errors in Microdrives may occur with lower
voltage. Asking the customers about the recording condition:
whether it was inside the car in winter, right after getting off the
car or in the carpeted area of a hotel etc., is recommended to in-
vestigate failures with poor reproducibility.
2.1.2.3
Failures caused by power cut during the operation
When the power is cut off while writing the data on the Micro-
drive, writing failure occurs in the writing sector (512 byte). As a
result, an error will occur while reading the data.
The effects on the system, given by the bad writing sector, de-
pend on the types of the written files on the sector.
If it is user data, the recorded movie may not be replayed.
To prevent failure in writing, do not insert/ remove the Microdrive
or cut off the power unless otherwise indicated or needed.
"Read Sequential Error" may be detected if Full Check of the Mi-
crodrive is performed with the DDD.
NOTE:
"Read Sequential error" may be detected as a result of defec-
tive Microdrive disables the reading. Abnormal reading may
also occur when the user removes the power plug or the bat-
tery while the Microdrive is in operation; the writing is not com-
pleted and the reading cannot be performed normally.
In the latter case, the failure will be corrected by running the
Full Check after the DDD Clean Disk has been performed.
Running the Clean Disk is recommended when the recorded
movies cannot be read or the Read Sequential Error occurs.
If an error is detected even after running the Full Check, other
causes of the failures are considered.
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