Teac MT-20D-IO User manual

TEAC MT-2ST/20D-IO
STREAMING CASSETTE MAGNETIC TAPE UNIT
MAINTENANCE MANUAL

TEAC MT-2ST/20D-IO
STREAMING CASSETTE MAGNETIC TAPE UNIT
~~INTENANCE MANUAL
TEAC CORPORATION
fiN: 10 1(;03)4 -0/
REV. A

CONTENTS
3. THEORY OF OPERATION
3-1 Outline of construction and functions ••.••.....•..••..••••••••
3-1-1 Overall block diagram ......•..•.••.•.•.•..••....••....•••
3-1-2 Outline of mechanical section .••.....•.•.•.••...•••...•.•
3-2 Operation of data recording/reproducing system
(PCBA Drive Control) ..•••••••••.••••.•.••••.••.•••.•••••••••••
3-2-1 Read circuit ..........................................•..
3-2-2 Write circuit and erase circuit ••••••.•••.•••.•••••••••••
3-3 Operaiton of tape drive systm (PCBA Drive Control) ....••••..•.
3-3-1 Servo circuit •...•.••....•..•.•••.•••.•.••..••...••.•...•
3-3-2 Other control circuits ••..........•.....•••..•..•..••...•
3-4 "D/CAS" Interface control (PCBA Interface Control) ........... .
3-4-1 CPU .•.•.•..••••..........•..••••..................•.•.•..
3-4-2
3-4-3
3-4-4
3-4-5
3-4-6
3-4-7
3-4-8
ROM
RAM
Host interface control ........•••..•••......••••••.....••
DMAC
Counter/timer ........................................... .
Write/read control ..•.•.....••..•.•••....•......•.....••.
I/O port .....•••.•..•.••••..•....•••••..•••.••.•..•..••••
301
301
304
311
311
315
317
317
319
321
322
323
323
324
328
329
330
334
3-5 "SCSI" Interface control (PCBA Interface Control)............. 335
3-5-1 CPU. . . . . . . . . . . . . . •• • • . . • . . . . . . • . . •• • • • . . . • . • • . . . . . • • . • • • . 336
3-5-2
3-5-3
3-5-4
3-5-5
3-5-6
3-5-7
3-5-8
ROM
RAM
Host interface control ......••.•...........•..............
DMA.C •••••••••••••••••••••••••••••••••••••••••••••••••••••
Counter/timer ..........•............•....•.......•••.•••.
Write/read control ..••......•...•.•.•..•••.•.••.....••.•.
I/O port ................••.............••.........••.....
337
337
338
344
345
346
350
3-6 "BASIC" Interface control (PCBA Interface Control)............ 351
3-6-1 Configuration .........••.................•.........•..... 351
3-6-2 Theory of operation ...•.....•..........................•• 354
- i -

3-7 Functions of test points, variable resistors and straps ..•.... 359
3-7-1 Functions of test points .............•....•.......•...... 361
3-7-2
3-7-3
Functions of variable resistors ••.....••....•.........•..
Functions of straps .•.....•.•..•••..••••......•........•.
377
379
4. MAINTENANCE
4-1 Outline of maintenance ...••.•..•....•••........•••••.••.•••.•• 4001
4-1-1 Routine maintenance ..•.•.•.....•••......•••.•....•••.•••. 4001
4-1-2 Check and adjustment .•...••....••......•..••••..••.•••••• 4002
4-1-3 Maintenance parts ....•.•..•.•........••••••.•......•...•• 4004
4-1-4 Maintenance articles .••...•.•..•.••.....•........•..•.••. 4007
4-2 Precautions on maintenance ••..•••..•.•••....•...••...••••...•• 4009
4-2-1
4-2-2
4-2-3
4-2-4
4-2-5
4-2-6
4-2-7
Screw tightening torque and screw lock (red) .•••..••...•. 4009
Connector handling method ••••••..••...•.•••••.•.••••.•.•. 4010
How to handle the protector guide •...•••••.••...••.....•. 4015
Cable treatment within chassis .•••••..•......••.••...•.•. 4017
Initialization of SOA
Initialization of SOB
Initialization of SOD
4019
4021
4023
4-2-8 Initialization of SOE •.....•..••.••..•••••..•.•..•.•..••. 4025
4-3 Check and adjustment procedures .......•......•.•••••...•...•.. 4027
4-3-1 Positional adjustment of reel motor (F), (R) Ass'y .....•• 4027
4-3-2
4-3-3
4-3-4
4-3-5
4-3-6
4-3-7
4-3-8
4-3-9
4-3-10
4-3-11
4-3-12
4-3-13
4-3-14
Height adjustment of encoder roller
Check of rotary direction of reel motor •••••••.......•.••
Check of file protect sensor ....•••....•••.........•....•
Cassette loading/unloading check •••....••.•........•.....
Check of head shift ....•....•.....••.......••........•..•
Check and adjustment of tape winding .•.•......•..........
Check and adjustment of head alignment .....•.............
Check of AGe operation •.........•...•...............•....
Check and adjustment of BOT/EOT hole sensor ..•...•....•..
Check and adjustment of tape speed .•.....••.••...•..•..•.
Check of start/stop time ........••.......••......•.•..•..
Check of ISV .....•........•....•••........•..•......•....
Check and adjustment of read preamplifier level ......•...
- ii -
4029
4032
4034
4036
4037
4038
4042
4048
4050
4054
4058
4060
4062

4-3-15
4-3-16
4-3-17
4-3-18
4-3-19
4-3-20
Check and adjustment of read level ....•...•...•......•...
Check of feed through .....•..............•••..•.•....••..
Check of resolution ...••.•••..••..•...•....••..•••••.•.••
Check of earse level ••......••••••.••.•...••.....•..••.•.
Check of peak shif t ..•..•..••.••..•..••..••....••••...•.•
Check of asymmetry ..•..••......•.•.••..•..•••••....•••••.
4-3-21 Check and adjustment of VFO operating point •••••••••.••••
4-3-22 Overall check .••••••..•....•.•....•••••........••.•..••..
4-4 Replacement of maintenance parts .••.••.•••••...•..••••...••••.
4-4-1 Replacement of head Ass'y ••....•.•.••••.•...••••.•......•
4-4-2 Replacement of reel motor (F), (R) Ass'y ••.•..••..•..•...
4-4-3
4-4-4
4-4-5
4-4-6
4-4-7
4-4-8
4-4-9
4-4-10
4-4-11
4-4-12
Replacement of interrupter C Ass'y
Replacement of LED hole sensor Ass'y •••..•••••.•••••...••
Replacement of sensor guide Ass'y ..•.•••.••••••••••••.••.
Replacement of encoder Ass'y, encoder roller .••.•.•..••••
Replacement of solenoid Ass'y •.••...••.•.•••••.••....•••.
Replacement of head base Ass'y •.••.•••••••••••••••.••••..
Replacement of PCBA Drive Control •••...•.•••••.•.••.••.•.
Replacement of PCB A Interface Control ••••.....•••..•..•.•
Replacement of front bezel .••..........••.••.•••..•......
Replacement of ej ect button •.....•......••.....•...•..•••
5. DRAWING AND PARTS LISTS
4064
4066
4067
4069
4070
4071
4072
4074
4078
4078
4083
4087
4090
4093
4095
4100
4105
4111
4112
4113
4115
5-1 Configuration. ••••.• •• . • • . .••.• . . ••. . . . ••• • •••••• . ••••• • • •• . • . 501
5-2 Disassembly drawing and parts lists of mechanical section .•••• 506
5-2-1 Mechanical parts of MTU ...••••...••.•.••.••.••••••...•... 506
5-2-2 Screws and washers
5-3 Parts list of PCB Ass'y
5-3-1 PCBA Drive Control
5-3-2
5-3-3
PCBA Interface Control ...................... ~ ......•.....
In terrupter C Ass' Y ..................•.....•........•..•.
509
510
511
520
526
5-4 Circuit diagrams and parts location diagrams ......•.........•. 528
5-4-1 Overall circuit diagram ......•.......••...•....•......... 529
5-4-2 PCBA drive control....................................... 531
5-4-3 PCBA interface control................................... 538
- iii -

Fig. 301
Fig. 302
Fig. 303
Fig. 304
Fig. 305
Fig. 306
Fig. 307
Fig. 308
Fig. 309
Fig. 310
Fig. 311
Fig.
312
Fig. 313
Fig. 314
Fig. 315
Fig. 316
Fig.
317
Fig. 318
Fig. 319
Fig.
320
Fig. 321
Fig. 322
Fig. 323
Fig. 324
Fig. 325
Fig. 326
Fig. 327
Fig. 328
Fig.
329
Fig.
330
Fig. 331
Fig.
332
FIGURES AND TABLES
Overall block diagram •..•••••••••••••.••••••.•.••••••••.••• 301
Cassette tape loading/unloading mechanism .•••••.•••••••••••
Cassette loading. and unloading
Cassette tape face identifier mechanism ••••••••••••••••••••
Read shif t mechanism ...................................... .
Cassette tape loading detection mechanism •••••••••.•••••.••
Write inhibit hole detection mechanism ••••••••••••.••••••••
Marker detection mechanism
Read
circuit block diagram
306
306
307
309
310
310
310
313
Example of operational waveforms of read circuit ••••••.•.•• 314
Write circuit and erase circuit block diagram •••••••••••••• 315
Servo circuit block diagram •••••••••••••••••••••••••••••••• 317
Other control circuits block diagram •••••.••••••••••••••••• 319
Interface bus timing •••••••••••.••••.••••••..••••••••••.••• 324
Host interface control circuit •••••.•••••••••••.•.••••••••• 325
Timing in write operation ••••••••••••••••••.••••••••••••••• 326
Timing
in read operation •••••••.••••••••••••••••••••••••••• 326
Channel 2 timing in write operation •••••••••••••••••••••••• 328
Write/read control logic block diagram •.•••••••••.•••••••.• 331
VFO circuit block diagram •..••••••••.•••.•••••••••••••••••• 332
VFO circuit timing ......................................... 332
Selection operation timing •••••••••••••••••••.••••••••••••• 338
Command transfer timing •••••••••••••••.•••••••••••••••••••• 340
Read data transfer timing
342
Channel 2 timing in write operation (30 ips) •••••.••••••.•• 344
Write/read control logic block diagram •••.••..••••••••••••• 347
VFO circuit block diagram •••.•..••••••.•.•••••••.•.•.••.••. 348
VFO circuit timing •••...••.••••••••.•••••••.••••.••••••...• 348
Hardware
block diagram ......•............ ..•.......... ..... 352
Initial control •••••••••.••••••••••••••.••••.••••••••.•..•. 354
Motion control ••.•••••..••.•••...•••••.•.••••.•••...•.•..•. 355
Tape
position management •.•.......•••.••.••••••••...••••.•. 356
-
iv -

Fig. 333
Fig. 334
Fig. 335
Fig. 336
Fig. 337
Fig. 338
Fig. 339
Fig. 340
Fig. 341
Fig. 342
Fig. 343
Fig. 344
Fig. 345
Fig. 346
Fig. 347
Fig. 348
Fig. 349
Fig. 350
Fig. 351
Fig. 352
Fig. 353
Fig. 354
Fig. 355
Fig. 356
Fig. 357
Fig. 358
RDP conversion
Cassette load delay •••••..•...•.•.•.•.........•....•.••....
Tach pulse conversion •.•.••.....•.•...•.....•........•.....
Positions of test points, variable resistors and straps •.••
Example of waveform at TP1 ....•.....••••..•....•......•••.•
Example of waveform at TP7 •••..•.•.•••..•..•.•....•...•••••
Example of waveform at TP8
Example of waveform at TP11
Example of waveform at TP13
Example of waveform at TP14
Example of waveform at TP1
Example of waveform at TP2
Example of waveform at TP3
Example of waveform at TP4
Example of waveform at TP5
Example of waveform at TP6
Example of waveform at TP9
Example of waveform at TP1
Example of waveform at TP2
Example of waveform at TP3
Exmaple of waveform at TP4
Example of waveform at TP5
Example of waveform at TP6
Example of waveform at TP1
Example of waveform at TP2
Example of waveform at TP3
357
357
358
359
361
362
362
363
364
364
366
367
367
368
368
369
370
371
372
372
373
373
374
375
375
376
Fig. 359 Example of waveforms at TP4 and TP5 ..•.....•....•..•.•..•.. 376
Fig. 401 Connector types ........•.••................................ 4011
Fig. 402
Fig. 403
Fig. 404
Fig. 405
How to extract the connector
How to insert the connectors
Sectional view of housing (black connector) ............... .
Terminal numbers
4012
4012
4013
4013
Fig. 406 Handling methods for connector J9 ..................•....... 4014
- v -

Fig. 407
Fig.
408
Fig.
409
Fig.
410
Fig. 411
Fig.
412
Fig. 413
Fig.
414
Fig.
415
Fig. 416
Fig.
417
Fig.
418
Fig. 419
Fig.
420
Fig.
421
Fig.
422
Fig.
423
Fig.
424
Fig.
425
Fig.
426
Fig.
427
Fig.
428
Fig.
429
Fig. 430
Fig.
431
Fig.
432
Fig. 433
Fig.
434
Fig. 435
Fig.
436
Fig.
437
Fig.
438
Fig. 439
Fig.
440
How to detach the protector guide
How to attach the protector guide
4016
4016
Cable treatment within chassis •••...••.•......•.•.........• 4018
Setting of SAO MODE switch •.•...••.•••..••.•........•.•.... 4019
Connections of SOA
Connections of SOB
Connections of SOD
Connections of SOE
4020
4022
4024
4026
Positional adjustment of reel motor (F), (R) Ass'y ....••••. 4028
Set ting of J l.gs ..••.•.•...•..•••.•.•.••....••••••••..••...• 4030
Height adjustment of encoder roller ..•......•••••••...••... 4031
Bonding of encoder roller
4031
Check of rotary direction of reel motor ....••••••••.•.•.•.. 4033
Mounting of FPT J l.g •.••.•••.••••.••••..••••••..•••••.•.•••. 4035
Check of file protect sensor •.•••.•••..•.••.•......•••..••. 4035
Loading of mirror cassette •....•...••••••.•.••.••••••..•••• 4040
Tape movement check (tape guide) ..•.............•..••...... 4041
Tape movement check (encoder roller) ....•.................. 4041
Burst signal ...........•.................••.......•..•..•.• 4043
Adjusting screws of head alignment .....................•... 4047
Check of AGC operation
Check of AGC operation
Hole detection waveform at TP13
Hole detection waveform at TP13
4048
4049
4051
4053
ISV
measuring method ..••.••••••..•..•.••...••••.••••.•••.•. 4060
Measurement of read preamplifier level ..................... 4062
Indication of Error Count on SOD
Replacement of Head Ass'y
Replacement of Head Ass'y
Replacement of Reel Motor
Replacement of Reel Motor
Replacement of interrupter
Replacement of interrupter
Replacement of
interrupter
(F) , (R)
(F), (R)
C
Ass'y
C
ASs'y
C
Ass'y
- vi -
Ass'y
(1)
...............
Ass'y (2)
...............
(1)
· ....................
(2)
· .....................
(3)
· ....................
4076
4080
4082
4085
4086
4088
4089
4089

Fig. 441
Fig. 442
Fig. 443
Fig. 444
Fig. 445
Fig. 446
Fig. 447
Fig. 448
Fig. 449
Fig. 450
Fig. 451
Fig. 452
Replacement of LED hole sensor Ass'y ••••••••••.••••••..•.•.
Replacement of sensor guide Ass' y •..••••.....••.•••..••••••
Replacement of encoder roller •••..••••••••••.••••••••.•.••.
Replacement of encoder Ass'y ••••••••.•••••••....•••.••.••.•
Setting of tilt adjusting jig ............................. .
Tilt adjustment
Replacement of solenoid Ass'y (1)
Replacement of solenoid Ass'y (2)
Positioning of head base Ass'y
Replacement of head base Ass'y (1)
Replacement of head base Ass'y (2)
Replacement of head base Ass'y (3)
Fig. 453 Replacement of front bezel Ass' y .......................... .
4092
4094
4097
4098
4099
4099
4102
4103
4104
4109
4109
4110
4114
4115 '
Fig. 454 Replacement of eject Button .•••••••••••••••• ' •••••••••••••••
Fig. 501
Fig. 502
Fig. 503
Fig. 504
External view (1)
External view (2)
External view (3)
External view (4)
502
503
504
505
Fig. 505 Disassembly drawing of mechanical section .••••••••••••••.•. 508
Fig. 506
Interrupter C Ass'y 527
Table 301 Write/read signal corresponding table ••.••••••.•••••••••.. 328
Table 302 Write/read signal correspoinding table •.•.•••••••••••••••. 344
Table
401
Table 402
Table 403
Table 404
Table 405
Table
501
Table 502
Table 503
Routine maintenance items .••••••.••••••••••••••••••.••.•.• 4001
Check and adjsutment items .....••••.•.••••••••••.•••.••••. 4002
Maintenance parts list ..•.......••••..•.•••••••..•.•.••..• 4005
Screw tightening torque .................................... 4009
Connection of reel motors ••.••••.••.•••••....••.......•... 4084
Main components configuration of MTU ..••••••••••..•.••.... 501
Parts list of MTU .••..•...•..•••••..•..•••......••.•...... 506
List of screws and washers ....•••...•.••...•••...•..•..... 509
- vii -

- How to Display Model Classification -
More
than one model is available according to specifications in the MT-2ST
Series. Sections 3 and 4 of this maintenance manual provide the descrip-
tions in common to all the models, unless otherwise specified. However,
partially there are special descriptions whose application is limited only
to particular models represented by the following symbols:
"90 ips"
"30 ips"
"Permalloy head"
"Ferrite head"
"D/CAS"
"SCSI"
"BASIC"
Applied only to the models in which the tape speed is
90 ips (inch per second) during data write/read opera-
tion.
Applied only to the models in which the tape speed is
30 ips during data write/read operation.
Applied only to a model on which the parmalloy head is
mounted.
Applied only to a model on which a ferrite head is
mounted.
Applied only to the D/CAS interface model.
Applied only to the SCSI interface model.
Applied only to the BASIC interface model.
- viii -