OTARI MTR-90 Operating instructions

053-039
TR-90
MASTER TAPE RECORDER
OPERATING AND MAINTENANCE MANUAL

PA GE
1- 1
1 - 2
2- 1
2- 1
2- 9
2-
11
2-14
3- 1
3- 7
4-1
4- 1
4- 2
4- 3
4- 5
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4- 7
4- 8
4- 9
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6- 1
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SECTION
I
1.1
1 . 2
II
2.1
2 . 2
2 . 3
2.4
2 . 5
III
3.1
3.2
IV
4 . 1
4.2
4 . 3
4.4
4.5
4 . 6
4 . 7
4 . 8
4 . 9
v
5.1
5.2
5 . 3
5 . 4
5 . 5
5.6
5 . 7
5 . 8
5 . 9
5.10
5 . 11
5 . 12
5.13
5 . 14
5.15
5 . 16
VI
6 . 1
6 . 2
6 . 3
OTARI MTR - 90 MANUAL
TABLE OF CONTENTS
TOPIC
INTRODUCTION
OTARI
MTR - 90 Master
Tape Machin e
Using this Manual
INSTALLATION
Preliminary
Inspection
Assembly of Remote
Contro l Box to its Stand
Assembly of Remote
Control Bo x and Auto L ocator
to Common Stand
Connections
BASIC OPERATION AND FUNCTIONAL CHECKOUT
Transport Functional Checkout
Remote Control Bo x (Remote Box) and Audio
Electronics Functional Checkout
AUDIO ALIGNMENT
General Description
Demagnetizing the Heads and Tape Guidance Path
Cleaning the Tape Path
Repro Amp Alignment
Sync Amp Alignment
Bias Alignment
Record Alignment
Phase Compensation
Gain Structure
TRANSPORT ALIGNMENT
General Description
Head Geometry
Transport Cover Plate Removal and Replacement
Swing Arm Travel
Tape Arming Solenoids
Fast Forward/Rewind Damping Solenoids
Swing Arm Tension
Tape Lifter Mechanism
Brakes
Reel Turntable Height
Reel Tension Servo
Capstan Servo
Adjustment of Transport PCB Assembly
Adjustment of Master CPU PCB Assembly
Adjustment of I/O PCB Assembly
Adj ustment of Bias Control PCB Assembly
OPERATION
General
Recording Initial Tracks
Playback of Initial Tracks
v

PAGE
6 -4
6- 5
6- 6
6- 7
6- 7
6- 7
6- 8
6- 8
6- 10
6- 10
6- 10
6- 11
7- 1
7- 3
7- 3
7- 3
7- 4
7- 4
7- 4
7- 4
7-5
7- 5
7- 5
7- 6
7- 6
7- 7
7- 8
7 -9
7- 9
7- 9
8- 1
8- 1
9- 1
9 - 1
9- 1
9- 2
9-2
9- 2
9- 3
9- 4
9- 4
SECTION
6 . 4
6 . 5
6 . 6
6 . 7
6 . 8
6 . 9
6 . 10
6 . 11
6 . 12
6 . 13
6 . 14
6 . 15
VII
7 . 1
7 . 2
7 . 3
7 . 4
7 . 5
7 . 6
7 . 7
7 . 8
7 . 9
7 . 10
7 . 11
7 . 12
7 . 13
7 . 14
7 . 15
7.16
7 . 17
7 . 18
VIII
8 . 1
8 . 2
IX
9 . 1
9 . 2
9 . 3
9 . 4
9 . 5
9 . 6
9 . 7
9 . 8
9 . 9
OTARI MTR - 90 MANUAL
TABLE OF CONTENTS
(continued)
TOPIC
Sel - Rep Recording (Overdubbing)
Sel - Rep Recording (Punch - Ins)
Rehearsal of Overdubs and Punch - Ins
Mix down
Use of the Cue Button and knob
Stop Erase
Use of the Variable Speed Mode
Use of an External Speed Reference
Voltage Conversion
Frequency Conversion
Bed Out
Serial I/O
AUTO LOCATOR
General
Tape Time
Locate Time
Stop Watch
Keyboard Numerals
Shift Left and Shift Right
Load
Memory Store
Memory Recall
+/ - Key
Direct Store , Direct Search and All Clear
Zero Set
Search Zero
Search
Shuttle
Auto Rewind
Transport Controls
Examples of Auto Locator Operation
16/24 TRACK CONVERSIONS
General
16 to 24 Track , or 24 to 16 Track Converston
Procedure
CIRCUIT DESCRIPTIONS
Pl ayback Head and Preamp
Speed Selection and High Frequency Playback EQ
Low Frequency Playback Equalization
Sync Playback
Output Stage
Input Circuitry
Audio/Bias Mixing Circuitry
Erase Head Driver
Reel Control Board
•
Vl
•

PAG E
10-1
1 0- 2
1
0-2
10 - 3
10- 3
10-4
10-4
10- 5
11-1
11-2
11 - 3
11 - 3
12 - 1
12-2
13 -1
1 3- 2
OTAR! MTR-90
MANUAL
TABLE OF CONTENTS
(continued)
SECTION TOPIC
x
10.l
10 . 2
10 . 3
10 . 4
10 . 5
10.6
10 . 7
10 . 8
XI
11 . 1
11 . 2
11 . 3
11 .4
XII
12 . 1
12 . 2
XIII
13 . 1
13.2
MAINTENANCE
General
Removing and Reinserting Printed Circuit Boards
Reel Motor Replacement
Brake Pad Replacement
Meter or Meter Lamp Replacement
Capstan and Tacho Roller Replacement
Head Shield Position Adjustment
Cleaning and Lubrication
SPECIFICATIONS
Tape Transport
Electronics
Physical
Accessories
PARTS LISTS AND DRAWINGS
General
Parts Lists
PARTS LISTS AND P.C . B. ASSEMBLIES
General
Parts Lists
• •
Vl.l.
•

SECTION I . INTRODUCTION
1 . 1 OTARI MTR-90 MASTER TAPE MACHINE
8 , 16 or 24 Track Recorder/Reproduce r
The Otari MTR - 90 records and reproduces 8- track , 16 - track , or
24 - track , l " or 2 " master tapes (as determined by the head as -
sembly and the quantity of audio circu i t b oards inserted in the
machine ' s card cage) . Tape handling i s gentle , yet positive and
fast , thanks to a symmetrical , constant - tension tape path.
Tension is distributed uniformly across the tape surface by a pair
of wide diameter pinch - rol l erless s pindles , the capstan and the
tachometer . This design eliminates cont a ct between the tape dr ive
and the oxide , allowing virtual l y un l imited safe passes of your
valuable master tapes . Mechanical integrity and long - term sta -
bility are ensured by a massive , precision · top plate and a uni -
tized , welded steel chassis . Ultra - high torque DC servo reel
motors provide fast winding , even with 1 4" reels , and ensure rapid
start-ups to full stable record/p l ay speed . The entire machine is
modular in construction , including the computerized transport con -
trol logic, for high reliability and serviceability .
The MTR-90 is loaded with features , such as selection for
external speed reference , vari - speed , or 2 crystal - locked speeds
(15 or 30 ips - 38 cm/s or 76 cm/s) . The reels can be gently rocked
back and forth for editing with the easy - to - use Cue control
knob , or by hand turning the capstan . Pushbuttons also provide
for tension release and retraction of the motor - driven head
shields to expedite editing . A practical splicing block as well
as a spot erase function for erasure of unwanted tracks , are also
provided in front of the head assembly .
Included as standard equipment is the Model CB - 113 Remote
Control Box . . rt duplicates the transport control buttons , and
provides individual function selections for each channel (Repro/
Sel - Rep/Input), master function selections for All Inputs , All Sel/
Rep and All Repro at once , and a master " All Safe " function . Also
located on the remote control bo x are a speed reference (VARI , FIX ,
EXT)
selector switch , a pitch control knob , and a digital readout
indicating speed by % or IPS .
The optional CB - 115 Memory Locator attaches to the same stand
as the CB-113 , and provides independent readouts and controls for
the elapsed tape time , locate time , and has a built - in stop- w atch .
The locator also features 10 keyboard assignable memories , (key -
board or direct tape time memor i es) and their direct recall , a
shuttle function for repeating any desired segment of the tape ,
zero cue , and other time saving functions . ·
The electronics are highly refined . A single - card approach
has been used for the record/play audio and bias circuits for each
channel , simplifying setup and service . Active mixing of audio
and bias in the record circuitry , proper utilization of high sle w
rate IC op -· amps, and discrete components at critical stages, al l
ensure the cleanest and quietest of recordings . There are, of
1 -1
•

course , individual channel calibrations for BIAS , as well as low
and high speed EQ and GAIN , also a low & high speed record PHASE
COMP trinuner is provided for improving complex wave - form charac-
teristics . In addition , a 3- position Master Bias selector (with
3 corresponding trinuners) enables the entire machine, once aligned ,
to be rapidly switched to accommodate the bias requirements of
different tapes . For further convenience, a single test input
jack applies your test/alignment signal to all inputs . There is
automatic switching between sync reproduce and input monitor when
the unit is switched between play and stop , fast winding modes and
of course rec/ready to record enable . Although dip - switches on
the transport control circuit card permit these logic functions to
be changed to suit the preference of the user .
Stable ACTIVE BALANCE Circuitry is adopted in the input cir -
cuit . In the output circuit , the balance to unbalance selection
can be obtained by a switch . (Optionally, either transformer out -
put or input can also be ordered.) In addition, a SERIAL I/O
CONNECTOR conforming to the RS-232C standard is provided for
direct conversation with a computer.
CAUTION: The DC reel motors develop substantial torque .
Never place a hand , clothing or other objects inside, atop
or ne ar a reel or swing arm when actuating the tape motion
controls. When using the Remote Session Controller or Auto
Locator, always make sure anyone near the transport is aware
of th e potential hazard posed by the high torque motors,
which are capable of increasin g tape tension with sufficient
speed and severity to damage the swing arms.
1.2 USING THIS MANUAL
The various sections
topics (i.e. , SECTION II .
SECTION 2.2 INSPECTION) .
topics are numbered (1, 2,
topics, the details may be
... etc . ) .
of the manual are divided by major
INSTALLATION) , and by sub-topics (i.e .,
Within a sub-section, the steps or
... etc.), and within these steps or
further divided alphabetically (A , B,
Normal parentheses ( ) are used for examples, and paren -
thetic comments . Square brackets [ ] are used for references to
callouts in certain illustrations . The square brackets in a given
sub - section are either all referenced to a particular illustration ,
as noted in that sub - section , or are individually referenced
(i . e ., Fig . 1-3 , [B] , meaning callout " B" in Figure 1-3).
Generally , we have used all upper case type to describe a
particular switch or control when that item is similarly labeled
on the actual equipment (i.e ., the PLAY button) . Where a switch
or function is not labeled , or the reference is less clear , we
capitalize only the first letter of the item (i.e. , the Cue con-
trol knob near the head assembly) . Machin e status or operating
modes are usually described with an upper case first letter (i.e. ,
1-2

you press the PLAY button to place the machine in Play mode) .
The functional checkouts in Section III should be carefully
performed when the MTR-90 is first installed. You will probably
learn a good deal about how the machine operates while following
this procedure, but it is not intended as a guide for recording
and editing; that information is presented in a more useful format
in Section VI.
Although this manual is intended for l" SCH, 2" 16CH and 2"
24CH operations, the following description deals only with 2"
24CH operation. Please note that all explanations apply to l" SCH
and 2" 16CH as well, even if remarks to that effect cannot be
found.
We encourage you to read this manual carefully now, and to
again review it after you have had a while to become familiar with
the MTR-90 . The more you know about your machine, the more you
can benefit from its many versatile features.
-
Figure 1 -1. MTR-90 Master Tape Recorder .
1 - 3
•

..
Figure 1- 2 . Tape Transport Controls.
Figure 1- 3. Cue Button and Cue Control Knob.
1 - 4

•
Figure 1-4. VU Meter Panel (24-track or 16/24 track version).
...
..
...
• •
• -
...
...
•
...
• • • • • • • • • l •
--•
... ..
. ...
.,,...
••
w -•
•
..
",,.,.. ..
••
··"'~
.. ft . ,
...
••• •
..
Fi gure 1- 5 . MTR - 90 Upper and Lower Circuit Card Cages.
1-5

•
.
t
t
t
'
t
t
'
~
'
'
'
t
t
\
• '
• t
t ' ' '
t t ' t
' •
~
t • t ' t
i t ' ' ' '
' t ' t
' ' ' ' '
' "
' ' I '
c.
\ t t ' '
t '
~
'
t ' '
' ' '
i ' ' • '
' ' ' '
' ' " ' '
' ' t
\ " ' '
' ' ' t '
t ' :
~
' ' }
Figure 1-6. Removal of PCB from Upper Card Cage
(24 - track cards illustrated).
--------
1 a • 1 • 1 • •
•
-
Figure 1-7. MTR - 90 Power Switch, Circuit Breakers,
and Pilot Lamps.
CAUTION: NEVER ATTEMPT TO OPERATE THE MTR - 90 IF
ANY OF THESE PILOT LAMPS DOES NOT LIGHT WHEN POWER
IS SWITCHED ON. CHECK THE CIRCUIT BREAKERS, AND
RESET IF POSSIBLE .
1 - 6

Figure 1- 8 . Audio Input and Output , Remote Control , Auto Locator
and Power Connections on the MTR - 90 Rear Panel •
Figure 1- 9.
NOTE:
• a
•
~~~·······
• • •
•••••• ;,;,;,;,
0000
sees
..
• D
1?
/11 /111_ -1
..
15
..
-
~
-
' a
.:It
•
j ~ ..,. .J
-,-
.· ,~~-: ~ ....... ~;.~ •• - ~
... . . . . . . . .
.. . . . .· . . . . .
-a Cjf~ . . : . .- ·.-· - ~ ·-·· ..
~
Auto Locator (CB-115 , Optional) - top , and
Remote Control Box (CB-113, Standard) - bottom
Roll-around stand shown.
1 - 7
•

SECTION I I. INSTALLATION
2. 1 PRELIMINARY
NOTE : Most MTR-90 ' s are uncrated and pre - tested by local
OTARI dealers , making the following unpacking and chekout
procedures unnecessary .
The MTR -90 Recorder , CB - 113 Remote Control Box , logic and
power cables , brackets and other related items are shipped par -
tially assembled . Open crates carefu l ly , and save packing
materials at least until proper operation has been verified .
After unpacking all components and assembling them as per instruc -
tions , you will be ready to connect the power and test the system .
NOTE : The MTR - 90 weighs approximately 400 pounds (200 kg) .
At least two strong people should work together during
unpacking and the initial setup to avoid physical strain
and to ensure gentle handling of the equipment .
2 . 2 INSPECTION
Before you make any electrical connections , the equipment
should be inspected visually . If there is any evidence of damage
due to rough handling in shipping , it is your responsibility to
notify the carrier and submit a claim. Do not connect or attempt
to use the MTR -90 and accessories until you have made this
inspection .
1. Inspect the equipment for any parts which may have become
loosened or damaged during shipping .
2 .
Check the plug - in printed circuit cards in the card cages:
A. Grasp the top of each door in t he front of the MTR-90 ,
and pull toward you to open them .
B.
The upper card cage should contain the proper quantity
of Audio boards (i.e. , 8, 16 or 24) . 8 & 16 track ver -
sions of the MTR -90 will have no cards in slots 9 - 24 or
17 - 24 , respectively .
C. The lower card cage should contain the Power Supply and
Boards 1 - 7 installed in t he correspondingly numbered
card slots .
#1 Reel Control
#2 Capstan Control
#3 Transport Control
#4 Master CPU
#5 I/O Control
#6 Tape Counter
#7 Bias
D. Remove the #3 board and examine the 4- position DIP switch
(SW - 1 on Figure 2-1) .
2
-1

SW1
-i~
C90
Figure 2- 1 . DIP logic selector switch on transport
control circuit card (card #3) .
The #1 , #2 and #3 switches should be on . These switches
are for selecting STAND - BY mode and INHIBIT mode , and
select a function which changes the Output Monitor to INPUT
automatically pursuant to the following transport condi -
tions : when SAFE-READY switch is set to the READY position
and when ALL REPRO or ALL SEL-REP mode of the Remote Con -
trol Box has been selected .
Switch No.
Transport
Function
SW - 1- 2 cancels the function
SW-1- 1 HAND
SPOOL
at ON position,
when TAPE • is
. CAPSTAN
moved by hand with
the cap -
stan in STOP mode.
SW - 1-2
STOP
Switches to INPUT Monitor
•
in
STOP mode.
SW - 1-3
FAST WIND
Switches to INPUT Monitor
•
in
FAST WIND mode.
ON/OFF switch for muting is
SW-1-4 PLAY START
provided until the transport
stabilizes
at PLAY speed .
Switches for selecting the functions of the Head shield
have been mounted on this Control PCB Assembly for later
models (from machines with serial number containing "B"
suffix, on) . The functions of these switches are as
follows.
2-2

0 1
SW - 1 Shield
doesn ' t move
Shield retracts
.
in
•
fast wind mode .
fast wind mode .
in
s~~ - 2
Independed button
Shield
retracts
•
in
control over
shields Unload
mode.
•
unload . in
SW - 1 and SW - 2 have been set to 0 and 1 , respective l y ,
when shipped from the factory .
E .
Remove the #7 card and examine the DIP sw i tches (SW3 ,
SW5, SW6) (Figure 2-2) . Make sure that the correct
selection has been made in accordance with the specifica -
tions of the machine . These slide switches set the
Reproduce EQ for either NAB or IEC standard at 15 ips ,
or AES or IEC at 30 ips; see Figure 2-2, and the chart
on next page .
IC 18
~o
IC 17
IC1
D
._____.Q
0
Figure 2- 2. DIP Repro EQ selector switches on
the bias control card (card #7) .
2- 3

Reproduce EQ Selection : Settings of SW3, SW5, SW6 on
Circuit Card #7
TAPE SPEED EQ CURVE
TIME CONSTANT SWITCH
POSITION
30
• AES
17.5
ips
).1 s + infinity SW6 ON
30
•
IEC
35.0 ).1 s + infinity
SW6
ips
OFF
15
•
NAB 50.0 ).1 s +
3180 µ S
SW5
OFF
ips
SW3 OFF
15
•
IEC 35.0 ).1 s + infinity
SW5 ON
ips
SW3
ON
Cue Level Attenuation Selection: SW4 on Card #7
TAPE SPEED
CUE
LEVEL AT FAST WIND/REWIND SWITCH
POSITION
15/30
•
ips
Attenuated
SW4
ON
15/30
•
ips
Not Changed
SW4 OFF
F . All cards should be firmly seated in their mating con-
nectors , and in the correct locations.
G. Close the doors to the card cages.
3. From the front of the machine, check the connectors and com -
ponents beneath the MTR - 90 transport, as follows :
A.
Remove the 3 allen head cap screws along the slot in the
front of the unit , just above the VU meter panel . The
meter panel is hinged along its lower edge, and is now
held closed by friction from rubber gaskets.
B. Grasp the rail just below the screw holes, and gently
pull toward you, don't drop it suddenly, pivoting the
meter panel open until its safety latches hold it in a
horizontal p osition.
c. Check the various connectors to
mated. (Refer to Figure 2- 3.)
be sure
Check:
they are firmly
l. · The connector on the bracket for each takeup reel
motor ass ' y.
2 . The 3 connectors located on the head shield retraction
mechanism (beneath the head assembly) .
3. The connector on the sensor beneath each swing arm
assembly.
4 . The connector on the tachometer (beneath the tacho -
meter roller on the supply reel side of the transport) .
• 2- 4

Figure 2-3. Connectors to be checked from front of machine.
5. The 3 connectors near the tape lifter solenoid (below
the head assembly on the supply reel side) .
6. The connector's on the capstan motor circuit boards,
and the connector which is located below the head
assembly near the capstan motor.
7. The 3 connectors on the VU meter P.C.B. ass ' y and
various small connectors for the READY-REC LED
P.C.B.'s.
D. Check for any obviously loose or damaged components, and
any cut or broken wires. Then close the meter panel and
reinstall the 3 screws.
4. From the rear of the machine, check the connectors and com-
ponents behind the upper card cage, as follows:
A. Remove the 6 phillips head screws, dress washers, and
nylon washers that secure the edges of the middle panel
on the back of the machine (the one with the XLR connec-
tors). The panel is hinged along its lower edge, and by
gently pulling the top toward you, it will pivot open
until its safety latches hold it in a horizontal
position.
B. Remove the 4 phillips head screws, dress washers, and
2 - 5

nylon washers that secure the edges of the top panel on
the back of the machine (the one with the fan) . This
panel is also hinged along its lower edge.
C. Check the various connectors to be sure they are firmly
mated. (Refer to Figure 2-4A &B.) Check:
1. The many connectors located on the back of the upper
card cage mother board.
2. On the top panel there are three motor drive tran-
sistor assemblies. Each assembly has two large
connectors and three small connectors. Check these
connectors.
t
Figure 2-4A Connectors to be checked behind the upper
back panel o f the machine.
2-6

Figure 2-4B Connectors to be checked behind the middle
back panel of the machine .
D.
The SMPTE-CUE slide switch on left side of the upper card
cage mother board should be set to '' Off' ' position. This
switch is only used when you are externally linking the
MTR-90 to a suitable SMPTE (Society of Motion Picture and
Television Engineers) time code synchronizer . (Refer to
Section 6 . 10 . )
E . Check for any obviously loose or damaged components , and
any cut or broken wires . Then close the middle and top
panels, and reinstall the phillips screws , dress washers
and nylon washers.
CAUTION : When closing this back panel, use care to en-
sure that no wires are pinched between the panel and the
MTR-90 chassis .
5 .
From the rear of the machine , check the connectors and com-
ponents behind the lower card cage, as follows :
2- 7
•

A. Remove the 4 phillips head screws, dress washers , and
nylon washers that secure the edges of the bottom panel
on the back of the machine (the one w ith the AC po w er and
logic connectors) . Lift the bottom of the panel away
from the machine , slide down an inch so its upper f l ange
clears the hinge screws of the panel above , then set the
bottom panel aside . (The electrical connectors are
mounted to sub - plates that remain attached to the MTR - 90
chassis . )
CAUTION : Be sure the AC power cable is not connected to
the MTR-90 at this time.
B. Check the various connectors and components to be sure
they are firmly seated . (Refer to Figure 2- 5 . ) Check:
1 . The many connectors located on the back of the lower
card cage mother board.
2. The 2 relays on the back of the lower card cage mother
board (they should be plugged in and secured with metal
retaining clips).
Figure 2- 5 . Connectors and components to be checked
behind the lower back panel of the
machine . (DS- lZ shown at rear right)
2 - 8

C. Check for any obviously loose or damaged components, and
any cut or broken wires. Then replace the panel, insert-
ing the upper flange first so it clears the hinge screws
of the panel above, and secure it with the 4 screws,
dress washers and nylon washers.
D. Remove the 5 phillips head screws, dress washers and
nylon washers that secure the cover panel on the left
side of the chassis. Check the several conn~ctors
mounted on the DS-lZ Power Supply Assembly for proper
engagement.
6. If minor faults or discrepancies are noted during the forego-
ing inspection procedures, make the necessary corrections
and/or adjustments, and proceed with installation.
IMPORTANT NOTE: If serious problems are apparently caused by
shipping damage, whether concealed or obvious, you must file
a claim with the delivering airline, freight line or other
carrier. You also must notify OTAR! or the nearest Otari
representative. Retain all packing materials for evidence in
damage claims. Failure to do so may weaken your claim! To
replace any parts under warranty, obtain from OTAR! or its
representative a return authorization form. DO NOT ATTEMPT
TO APPLY POWER OR OPERATE THE MACHINE UNTIL PROPER REPAIRS
HAVE BEEN COMPLETED.
2.3 ASSEMBLY OF RE MOTE CONTROL BOX TO ITS STAND
Refer to Figures 2-6A & B, and 2-7.
* Installation of Remote Control Box
The Remote Control Box is provided with a stand for desk top
use. The Remote Control Box can be tilted with the angle
adjusting knob for use at any convenient position.
* The Remote Control Box can be used with or without a roll-
around stand.
(1) Remove the two sections of the stand.
(2) Assemble the ZA-52J Stand Assembly in accordance with the
following figure.
(3) Put the Remote Control Box gently on the fitting arm and
attach the Box to the arm with four screws.
(4) Loosen the knob to adjust the angle. Find the desired
angle. Then retighten the knob to hold the Control Box
at this angle.
2-9