(3) Low voltage sensor
The low voltage sensor is equipped to protect the FDD from erroneous
operation due to the internal circuits construction of the FDD during
unstable state of the supplied voltage such as at power on or off.
The output of this sensor is ANDed to all the output drivers of the FDD.
Therefore, in the unstable state of +5V and +12V powfer when the internal
logic of the FDD does not function normally, it protects erroneous
operations of write driver and erase driver, erroneous signal output
to the host system, and etc.
+5V power
Low voltage
output
(U9,pin 17)
Power on
Power off
Note: Dotted line shows the LVS input pin 34 of U6 ,
control LSI.
___
(Fig.307)r Low voltage sensor waveforms
314
Summary of Contents for FD-55 Series
Page 7: ...SECTION 3 THEORY OF OPERATION 300...
Page 8: ...3 1 CONSTRUCTION AND FUNCTION 3 1 1 General Block Diagram Fig 301 General block diagram 301...
Page 23: ...Fig 308 Control circuit block diagram 316...
Page 40: ...SECTION 4 MAINTENANCE 4000...
Page 56: ...J4 J12 Option J9 J5 Top view of the FDD Fig 401 Types of connectors 4016...
Page 95: ...Note Refer to item 4 2 1 as to handling of the set screw 4057...
Page 102: ...k Key in Cl SET TMAX L Confirm as in item j 4064...
Page 104: ...Notch B position TP6 voltage 0 5V Max LED indicator Fig 422 Check of file protect sensor 4066...
Page 125: ...k Eject the level disk and release the Invert and ADD modes of the oscilloscope 4087...
Page 136: ...Fig 431 Adjustment track alignment 4098...
Page 153: ...Fig 436 Adjustment of index sensor 4115...
Page 172: ...Fig 440 Replacement of head pad 4134...
Page 176: ...Plate Fig 441 CSS Ass y and shift lever position 4138...
Page 177: ...SECTION 5 DRAWINGS PARTS LIST 500...
Page 179: ...r Fig 501 External view No l 502...
Page 181: ...PCBA DD motor servo Fig 503 External view No 3...
Page 182: ...Fig 504 External view No 4 505...
Page 183: ...Partis nrnnber of the FDD Fig 505 Extemal view No 5 506...
Page 188: ...Fig 506 Mechanical section break down 511...
Page 199: ...PCBA DD MOTOR SERVO PARTS LOCATION Type S i 522A...
Page 200: ...PCBA DD TOR SERVO PARTS LOCATION Type TO 522B...
Page 201: ...PCBA DD MOTOR SERVO PARTS LOCATION Type G 522C...
Page 202: ...PCBA DD MOTOR SERVO PARTS LOCATION Type T 522D...
Page 204: ...523B PCBA DO MOTOR SERVO SCHEMATIC Type K...
Page 205: ...o 523C i 1 PACB DD HOTOR SERVO SCHEMATIC Type G...
Page 206: ...CV 5 3 3 H 2SV 523D PC DD M o t o r SERVO SCHEMATIC Type T...
Page 207: ...PCBA MFD CONTROL B PARTS LOCATION PCB ISSUE A G 524A...
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Page 209: ...PCBA FRONT OPT PARTS LOCATION 525 PO I...
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