Drive select gate classifies the external input signals into several
functions and transmits them into the control LSI.
The selection of straps (short bars) determines the select condition
of the drive, head load and spindle motor operating conditions,
and
turn-on condition of the front bezel indicator.
Refer to items 1-11
and 1-12 of the Specification as to the detailed function of each strap.
The head load gate,
adding the pre-ready condition to the selected head
load command by the drive select gate, turns on the solenoid driver,
The head load gate also triggers the internal over-drive timer
constructed with a re-triggerable counter and maintains the over-drive
circuit on for a determined period (26msec,approx.).
During this period,
rf
12V power is applied to the head load solenoid to execute the drawing
action of the solenoid stably. -
To protect the head positioning error by the impact of the head loading,
the stepping motor is also over-driven.
After the completion of the
over-driving,
both the head load solenoid and the stepping motor are
maintained by +5V power to minimize the power loss.
The write/erase gate judges the FDD whether it can execute¿write
operation or not and issues write gate and erase gate -signals for the
write circuit.
A specified delay time is established in the erase
gate signal by an internal counter (refer to Fig,306). ^
The ready detector consists of speed detector, pre-ready latch, and
ready latch.
The output of the speed detector which is constructed
with a re-triggerable counter becomes always TRUE (HIGH) when the
rotational speed of an installed disk (soft sectored) is more than
50%, approx.
of the rated speed.
The pre-ready latch detects the
first index pulse (pre-ready condition) after the speed detector
detects the 50% of the rated speed. The output of the ready latch
becomes TRUE (HIGH) when the second index pulse after the 50% of the
rated speed, then the READY condition is informed to the host system
through the output driver,
U2 (pin 1 ^ 3 ) .
- 317
Содержание FD-55 Series
Страница 7: ...SECTION 3 THEORY OF OPERATION 300...
Страница 8: ...3 1 CONSTRUCTION AND FUNCTION 3 1 1 General Block Diagram Fig 301 General block diagram 301...
Страница 23: ...Fig 308 Control circuit block diagram 316...
Страница 40: ...SECTION 4 MAINTENANCE 4000...
Страница 56: ...J4 J12 Option J9 J5 Top view of the FDD Fig 401 Types of connectors 4016...
Страница 81: ...Collet shaft Front lever Gap between collet shaft and set arm hole Fig 412 Adjustment of set arm position 4043...
Страница 87: ...Fig 416 Adjustment of arm lifter Note Viewed from front bezel side Fig 417 Gap of arm lifter 4049...
Страница 95: ...Note Refer to item 4 2 1 as to handling of the set screw 4057...
Страница 97: ...j Repeat the procedure from item c to f Note Refer to item 4 2 1 as to handling of the set screw 4059...
Страница 102: ...k Key in Cl SET TMAX L Confirm as in item j 4064...
Страница 104: ...Notch B position TP6 voltage 0 5V Max LED indicator Fig 422 Check of file protect sensor 4066...
Страница 125: ...k Eject the level disk and release the Invert and ADD modes of the oscilloscope 4087...
Страница 136: ...Fig 431 Adjustment track alignment 4098...
Страница 153: ...Fig 436 Adjustment of index sensor 4115...
Страница 159: ...Head carriage Ass 1 Stepping motor capstan Guide shafts Fig 437 Replacement of head carriage Ass y 4121...
Страница 169: ...12 it is recommended to connect the FDD to the system for overall test Refer to item 4 2 5 1 4131...
Страница 172: ...Fig 440 Replacement of head pad 4134...
Страница 176: ...Plate Fig 441 CSS Ass y and shift lever position 4138...
Страница 177: ...SECTION 5 DRAWINGS PARTS LIST 500...
Страница 179: ...r Fig 501 External view No l 502...
Страница 181: ...PCBA DD motor servo Fig 503 External view No 3...
Страница 182: ...Fig 504 External view No 4 505...
Страница 183: ...Partis nrnnber of the FDD Fig 505 Extemal view No 5 506...
Страница 188: ...Fig 506 Mechanical section break down 511...
Страница 199: ...PCBA DD MOTOR SERVO PARTS LOCATION Type S i 522A...
Страница 200: ...PCBA DD TOR SERVO PARTS LOCATION Type TO 522B...
Страница 201: ...PCBA DD MOTOR SERVO PARTS LOCATION Type G 522C...
Страница 202: ...PCBA DD MOTOR SERVO PARTS LOCATION Type T 522D...
Страница 203: ...55 3 on I537Q2 5 or P S W Q U j k I J U C o fc I 3 W J V o 6 V y f t 523A PCPA DD MOTOR SERVO SCHEMATIC Type S...
Страница 204: ...523B PCBA DO MOTOR SERVO SCHEMATIC Type K...
Страница 205: ...o 523C i 1 PACB DD HOTOR SERVO SCHEMATIC Type G...
Страница 206: ...CV 5 3 3 H 2SV 523D PC DD M o t o r SERVO SCHEMATIC Type T...
Страница 207: ...PCBA MFD CONTROL B PARTS LOCATION PCB ISSUE A G 524A...
Страница 208: ......
Страница 209: ...PCBA FRONT OPT PARTS LOCATION 525 PO I...
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