OTARI MX-55T-M User manual

Parts No. OS3-207
[fJOSCJH
MX-55T-M, T, N-M
PROFESSIONAL RECORDERS
OPERATION AND MAINTENANCE MANUAL
SIXTH EDITION
Printed : May 1990
Ed .6 (GK)
Otari, Inc.

Copyright © 1989, 1990 Otari, Inc.
Printed in Japan
This manual may not be reproduced by any means without written permission .

CAUTION
To prevent fire or shock hazard:
Do not expose this unit to rain or moisture.
Do not remove panels (unless instructed to do so).
There are no user-serviceable parts inside.
Refer servicing to qualified service personnel.
PLEASE READ THROUGH THE SAFETY INSTRUCTIONS ON THE NEXT PAGE.

1. Read Instructions
2. Retain Instructions
3. Heed Warnings
4. Follow Instructions
5. Water and Moisture
6. Carts and Stands
7. Ventilation
8. Heat
9. Power Sources
1 D. Grounding or Polarization
11 . Power Cord Protection
SAFETY INSTRUCTIONS
All the safety and operating instructions should be read before the
device is operated.
The safety and operating instructions should be retained for future .
All warnings on the device and in the operating instructions should
be adhered to.
All operating and use instructions should be followed.
The device should not be used near water - for example, near
bathtub, wash bowl, kitchen sink , laundry tub, in a wet basement,
or near a swimming pool, etc .
The device should be used only with a cart or stand that is
recommended by the manufacturer.
The device should be situated so that its location or position does
not interfere with its proper ventilation . For example, the device
should not be situated on a bed, sofa, rug, or similar surface that
may block the ventilation openings; or, placed in a built-in installation,
such as a bookcase or cabinet that may impede the flow of air
through the ventilation openings.
The device should be situated away from heat sources such as
radiator , heat registers, stoves or other appliances (including
amplifiers) that produce heat.
The device should be connected to a power supply only of the type
described in the operating instructions or as marked on the device.
Precautions should be taken so that the grounding or polarization
means of the device is not defeated.
Power supply cords should be routed as they are not likely to be
walked on or pinched by items placed upon or against them, paying
particular attention to cords at plugs, convenience receptacles, and
the point where they exit from the device.
iii

12. Cleaning The device should be cleaned oll ' ly as recommended by the
13. Non-Use Periods
14 Object and Liquid Entry
15. Damage Requiring Service
16. Servicing
man ufactu rer.
The power cord of the device should be unplugged from the outlet
when left unused for a long period of time.
Care should be taken so that objects do not fall and i that liquids are
not spilled , into the enclosure through openings.
The device should be serviced by qualified service personnel when:
A. The power-supply cor ,d or the plug has been
damaged; or
B. Objects have fallen, or liquid has been spillled ' into the
appliance; or
C. The appliance has been exposed to r ain; or
D. The appliance does not appear to operate nor m ally or
exhibits marked change in performance; or
E. The appliance has been dropped, or the enclosure
damaged.
The user should not attempt to service the device beyond that
described in the operating instructions. All ot l her serv , ice should be
referred to qualified personnel.
iv

WARNING
This equipment generates, uses and can radiate radio frequency
energy and if not installed and used in accordance with the
instructions manual, may cause interference to radio communications.
It has been tested and found to comply with the limits for a Class A
computing device pursuant to Subpart J of Part 15 of FCC Rules,
which are designed to provide reasonable protection against such
interference when operated in a commercial environment. Operation
of this equipment in a residential area is likely to cause interference in
which case the user at this own expense will be required to take
whatever measures may be required to correct the interference.
v

COMMUNICATION WITH OTARI
FOR SERVICE INFORMATION AND PARTS
The Otari products are manufactured under strict quality control and each unit is carefully inspected and
tested prior to shipment.
If, however, some adjustment or technical support becomes necessary, replacement parts are required, or
technical questions arise, please contact your nearest Otaril dealer or contact Otari at:
Otarl, Inc.
4-33-3 Kokuryo-cho
Chofu-shi, Toky0182
Japan
Phone : [phone]
Telex
: J26604 OTRDENKI
Fax
: (0424) 81-8633
Cable
: OTARIDENKI TOKYO
Otarl Deutschland GmbH.
Rudolf-Diesel-Str.12
D-4005 Meerbusch 2 (Osterath)
F. R. Germany
Phone : [phone]
Telex : 8531638 OTEl D
Fax :[phone]
Otari (U. K.) Lt d.
22 Church Street Slough
Berkshire Sl1 1 PT
United Kingdom
Phone: [phone]
Telex : 849453 OTAR IG
Fax: [phone]
Otarl Corporation
378 Vintage Park Drive
Foster City
California 94404
USA
Phone : [phone]
Telex
: 650 302 8432 MCI UW
Fax : [phone]
Otari Singapore Pte., Ltd.
625 Aljunied Road
#07-05 Aljunied Industrial Complex
Singapore 1438
Phone : [phone]
Telex : RS 36935 OTARI
Fax: [phone]
Another part of Otari's continuing technical support program for our products is the continuous revision
of manuals as the equipment is improved or modified. In order for you to receive the information and
support which is applicable to your equipment, and for the technical support program to function
properly, please include the following information, most of which can be obtained from the Serial number
label on the machine, in all correspondence with Otari:
• Model Number:
• Serial Number:
• Date of Purchase:
• Name and address of the dealer where the machine was purchased and the power requirements
(voltage and frequency) of the machine.
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MX-55 Operation and Maintenance Manual
Table of Contents
Ta ble Df CDntents
Safety Instruc t/on s ... .. . .... .. .. ...... . .. . ... ............. . ....... ........ .. .. . .. . ................................... iii
Communi cat ion with Otarl .. ...... ...... ... .. .... .. ............ ... ....... ... .. . ..... ........... ..... ... .. . ...... vII
Sec tion 1 Introduction
1.1 MX -5 5 Seri es Tape Rec orders ....................... .. ........... . ................................. 1 ·1
1.2 U sin gT his Manua l ........ ... .............................. .. ....... .. ......... ....... .... .... ...... ...... .. 1 ·3
1.2.1 Orga ni zation .. ...... ...... .. . ..... .. ..... ... ...... ........ ...... .. ........ ..... .. ......... .... ....... 1 ·3
1 .2.2 Con vention sw ithin t his manual ..... ......... ...... .... ............... .... ...... .. .... . 1 ·4
Sec tion2 Controls and Indicato rs
2.1 Tap eT ra n sport .... ...... ........ .................... .. .................... . ................ ... ................ 2·1
2.2 T ransport Con t ro l Panel ....... .. .... ... .. ............... ...... .. .......... .. .... .. . ........ .. ........... 2·4
2.3 He ad Assembly ...... ..... .... . ..... .. . .... .. ..... .... .... ...... .... ......... ... ................. .... ....... 2 ·12
2.4 Amp li f ier Pane l .. .... ....... .... .......... . .... ... .... ..... ... ...... .. ...... .. ................ .. ....... ...... 2 ·13
2.5 Au d io Co nne cto r Pan el .... . .. .. ........ ... .. . ............. ... ............ . ........... .. ............... 2 ·18
2.6 T ransport Connec tor Pane l . ....... ... ...... ....... ....... ... ..... .... ...... .... ................... . 2·20
2.7 Controls on Audio Am plifier PC B Assembly ......... .. ....... .. ............ . .. . ..... .... 2·22
2.8 Contro ls on MicA mp li fier PCB As sembly .. .............. ...... .......... .. ............... 2·24
2.9 Con tro ls on Mother Boa rd P CB Ass embly .... . .. ..... .. . .. .... .............. . ...... .. .... 2·25
Section 3 Operation
3.1 M odes of Operation .. ... .. .... ...... ....... ... .... ..................... .... ..... .... ...... .... ............ . 3·1
3.2 M ou nti ng the R ee ls an dThrea ding the MX-55 . ...... .. . ...... ........ ..... ............. 3·4
3. 2.1 Pl acing the Ree lson the Machine ..................................................... 3·4
3.2 . 1. 1 Us i ng 5" or 7" EIA R eels ........ ...... ..... . .......... .. .......................... 3·4
3 .2.1 .2 Usi ng 10.5 " NAB Reels ............ ... . ...... .. .... .. .... ... .. ...... ... .... .. . ... .. 3·4
3.2. 1. 3 Using AEG (or DIN ) Hub s .. ...... .. ........... ....... .. .... ........ ... .......... 3·4
3.2 .2 Threading the tape ....... .. .. .... ..... ...... .. ......... .... ................. .. ........... .... ... 3·5
3.3 Tra n sport Modes .. .... ...... ..... .... ..... ...... .... .. .. . .. . .. . .. ...................... ..... ....... ... .... .. 3·6
3.3.1 Pl ay mode ... .................. . ..... . .. ... . .. ..... .... ..................... . ................. .... .... 3· 6
3.3 .2 Fast Forwa rd mode .. .... ...... .......... ................................... ........ .... ........ 3· 6
3 .3 .3 R ewind mode ........ ...... ........ ... .. .. ... .. ... ...... .... ...... .. ..... . .. .... ...... ..... .. . .... .. 3·6
3. 3.4 R ecord mode .. ..... ...... .... ..... . ... .. .......... ..... ..... . .......... . .......................... 3·6
3.3.5 Ed it R eady mode .... .. ............................... .. .. .. . ................ ..... .. .... .. ....... 3 ·7
3.3.6 Edit Pl ay mo de ............... ...... .. ........................................ ..... ...... .. ..... . ... 3· 7
3.3 .7 Cue mode .. ........... . .......... .. .......... .. . ......................................... . .......... 3· 7
3. 3.8 Vari Speed mo de ........... .. ... ... .... ....... .. .. . .. ............ ... ................ ........ .... . 3 · 7
3. 3.9 Presett ing th e Vari S peed amount ........ . .. ..... .. ... ....... . ... ........ ........... 3·8
3.4 Aud io Channel Modes ........... .... ...... . ................................................. ... .. .... ... 3·9
3 .4. 1 R ecord Ready mode .. . .. .. .. ..... .. .... .... .. .... ..... .... ..... ....... ... ............. .. ...... 3 · 9
3 .4 .2 Record Safe m ode ............................................................................... 3-9
3.4.3 Inpu t Monitor mo de ... ...... .... .. . ... .. ... .. .. ... .... ...... .. ................................ 3·9
3.4.4 Sel · Rep Monitor mode .. ............. .... .. . ................ . .... .... . ... ....... .. . .... .... 3-9
3.4 .5 Repro Mo nit or mod e .. ........ . .... . ............................. . .. ............. ....... . 3-10
3 .4. 6 Vo i ce Edit mode .. ........... . ............. .. ..... .... ...... ... .. ............ ...... ... ...... . 3- 10
3.5 Time Code Modes ....... .... .. .. ........ . .. . .. . ...... .... ..... ... .. ........... .. .... ...... ..... ... 3-11
3.5 .1 Record R eady mo de ....... ...... ... . ......... .. ...... .. . ..... .... ..... ... .... 3- 11
3.5 .2 Record Safe mod e . ......... .. ......... .... .. .. . ...... ....... ....... .. ...... ..... .... ......... 3-11
3. 5.3 Input Mon ito r mode .. .. ........... .... ...... ... .......... .. .. .. .. .. ..... .... ....... .. .. 3-11
3 .5.4 Sel · Rep Mon ito r mode .. ...... .. . .. . ...................................................... 3-11
3.5.5 R epro Mo ni tor m ode .... ... . ....... ........ .. ... ............................ ... ......... 3·11
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3.6 Auto Locator Modes .. . .... .. ........ .. ... .. . ... ... . ..... .. ........... . ... . ... .. .. ........ .. .. ........... 3 ·12
3. 6.1 Set mode ............................................................................................ 3 ·12
3. 6.2 Repeat mode ...................... .... ........ ....... .... .. ...... ...... ...... .. .... ...... .... ..... 3 ·13
3. 6.3 Search mode .............. .... ...... .. .......... . .......... .... .. ...... ....... ............ .... .... 3 ·13
3.6.4 Search Play mode .................... .. .......... .... ...... .... .................. ...... ...... . 3 ·13
3.6.5 Search Zero mode ........ .... ................................................................. 3 ·13
3.6 .6 Search Start mode ............ ........ ........ .. .... .......... .......... ........ .... .......... 3 ·13
3.7 Test Oscillator .. .... .......... .... ...... .... ............ ...... ............ .. ................................ . 3 ·14
3.8 Tape Editing ................................................................................................... 3 ·15
Section 4 Maintenance and Adjustment
4.1 Routine Maintenance .. .... .......... .. .. ........ ...... ............ .... .... ........ ...... ...... ........ ... 4·1
4.1 .1 Demagnetizing the Heads and Tape Path .......... ............ ....... ............ 4·1
4.1.2 Cleaning the Tape Path ...... ............................ .. .......... ........ ............ .. ... 4·2
4.1.3 Lubrication ...... ........ .... ............ .. .............. ............ .. .. .. ........................... 4·4
4.2 Transport Alignment Procedures ........................................................... ...... 4·5
4.2.1 Head Position Adjustment .... .... ..................... .... .. .......... ..... ...... ...... .. . 4· &
4. 2.2 Reel Table Height Adjustment .... .. .... .... . ........ .... ........... . .. ...... ... ......... 4·8
4.2.3 Reel Brake Adjustment ............ .. .............. . .... .. ...... . .... .. ............ ...... ... 4 ·10
4.2.4 Pinch Roiler Pressure Adjustment .... .... ........ .... .................. .. .......... 4 ·12
4.2.5 Tape Lifter Adjustment ............ ...... .......... .. ................ .... .......... .... ..... 4 ·14
4.2.6 Capstan Motor Servo Adjustment .......... ........ .......... ...... ...... ....... .... 4 ·15
4.3 Audio Alignment .... ................ .. .............................................. .. ..................... 4· 17
4.3.1 Tools and Equipment required .. .. ....................... .. ....... ........ ........ .... 4·17
4.3.2 Preliminary Adjustments ............ .. .. .. .......... .... ........ ....... ............ .. ..... 4 ·18
4.3. 2.1 Peak Indicator Level Adjustment ........ ............ ........ ...... ...... . 4 ·18
4.3.2.2 Test Oscillator Waveform and Level Adjustment ........ .... ... 4·20
4.3.3 Reproduce Electronics Adjustment .......... .. ........ .. .......... .... .. .......... 4·21
4.3.3.1 Precautions Before Making Adjustments ...... .............. ...... .. .. 4·21
4.3 . 3.2 Head Azimuth Adjustment ........ .. .............. .. .... .......... .... ........ 4·22
4.3.3.3 Reproduce Level Adjustment .......... .. ........ ...... .... .... ............ . 4·24
4.3 . 3.4 Reproduce Equalization Adjustment ... .......... ......... .......... ... 4·25
4.3.4 Record , Electronics Adjustment .................................... .. ................ . 4·26
4.3 . 4.1 Level Matching .. ...... ........ .... .... ...... .. .. ........... .. ........ .. .............. 4·26
4.3.4.2 Erase and Bias Current Adjustment .. .. .............. .... ............. .. 4·27
4.3. 4.3 Record Bias Level Adjustment .... ......................................... 4·28
4.3.4.4 Recor ·d Head Azimuth Adjustment ..... .... .. ....... .. .... ... ...... ..... 4·29
4.3.4.5 Record Level Adjustment ........ . .. .... ............ ..... ........... ......... .. 4·31
4.3.4.6 Record Equalization Adjustment ........... .. ............ .. ............... 4· 32
4.3.4.7 Low Frequency Reproduce Equalization Adjustment ........ 4·33
4.3.4.8 Sel·Rep Level Adjustment ...... ...... ....... .... .... .... ........ .. ............ 4·34
4.4 Time Code Channel Adjustment ......... .. ............ ...... ........ ...... .... ....... ..... .. . ... 4·35
4.4.1 Input/Output Level Adjustment ........................................ ... ......... . .. 4·35
4.4.2 Time Code Reproduce and Sel · Rep Level Adjustments .... ...... .... . 4·3&
4.4.3 Erase and Bias Current Adjustment ................. .... ....... .. .................. 4·36
4.4.4 Bias Adjustment ........................................... .. ............ .... .. .... ...... ....... 4·37
4.4.5 Record Level Adjustment ....................... . .............................. . .......... 4·37
Section 5 Installation
5.1 Uncrating and Inspection ........ .. ............ .. .... . ........ .... ............. .. ...................... 5·1
5.1.1 Uncratingthemachine ........ .... .......................... ...... .......... ..... ............ 5·1
5.1 .2 Inspection .... .............. .. .... ...... , ....... .. .......................... ............. ..... ...... ... 5·2
5.1. 2.1 Audio Amp PCB .......... .. . .... ....... .... .... .. ......... .... .. . ....... ..... .......... 5·2
5.1 . 2.2 Transport Control PCB .... ...... ................. ... ......... .. ................... 5·4
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MX-55 Operation and Maintenance Manual
Table of Contents
5.1.2.3 Power Supply Voltage Selector inspection .......... .... .... ... .. ....... 5·6
5.2 Connections .... ................... ... ............... . ....... .............................. . ........ .. .......... 5·7
5.2.1 Power Connection ............ .... .. .............. ............ ...... .. ........................... 5·7
5.2.2 Changing the Supply Voltage Requirement ..... ....... . .. . .... .. ............... 5·7
5.2.3 Connecting the Audio Signal .................................... .. ...................... . 5·8
5.2.4 Connecting the Remote Control Unit ............... ................... .. . .......... . 5·9
5.2.5 Connecting Time Code ...... .............. .... ........ . ...... .. . .. ............. .. . .. ....... 5 ·10
5.3 Prior to Operation ........................................................ .. . .. ... ........ .......... ....... 5 ·11
5.3 .1 User-selectable Functions ............... .. ................. ..... .......... .. ............ . 5 ·11
5.3.1.1 SEARCH 3 button functions .... . .. ..................... ...... ... .. .......... 5 ·11
5.3.1.2 Punch In Method Selection ...... .. ............... ................ .. .. ....... 5 ·11
5.3.1.3 Punch Out Method Selection . ...... ........ ... ...... .... .... ................ 5 ·11
5.3.1.4 Foot Switch Function Selection ..... .. .... ........... ...................... 5 ·12
5.3.1 .5 Fader Start Selection .................... ...... .. ..... ......... . .................. 5·12
5.3.1.6 Tape Speed and Reel Size Change .......... .. .. .. ....................... 5 ·12
5.3 . 1.7 Selection of Reference Flux Level .. .... ...... . .. .................... ..... 5·13
5.3 .1.8 Changing the speed version ............ ............... ............ .. ........ 5 ·13
5.4 Optional Accessories .................................... .... .. .... .............. ...... .... ........ ...... 5 ·14
5.4 .1 Installing the Accessories ...... ............ ....... .................. ...... .... ........ 5 ·14
5.4.1.1 Changing the Machine Feet for Horizontal Operation ....... 5 ·14
5.4.1.2 Installing the Optional 19" Rack Mount kit ............ ............. 5 ·14
5.4 .2 Optional Stands for the MX-55 .......... ............... .. . .................... 5 ·15
5.4 .2.1 Assembling the ZA-81 B-T without Spacer ......... .... .. .. ........ 5-15
5.4.2.2 Assem bling the ZA-81 B- T with Spacer .................... .. .... ..... 5 ·16
5.4 . 2.3 Assem bling the ZA-81 C-S .......... ..... .... .. ................... .......... .. 5·17
5.4.3 OptionallnpuVOutput Transformers .... ... ............... .. ................ . .... 5 ·18
5.4.4 VEM Unit Installation .. ....... ................ .... .... ................ .... .. ........ . .. ...... 5·20
5.4.4.1 VEM Installation on the MX-55T-M (MX-55N-M) ....... ...... 5·20
5.4.4 .2 VEM Installation on the MX-55T ................ .... .. .. .. ....... ......... 5·20
5.4.5 Operation Instructions for Voice Edit Mode .................................. 5·21
5.4.6 Mounting the Foot Switch Jack or Fader Control Connector ...... 5·22
5.4.7 Mounting the Proximity Sensor ........ .......................... ................ .... 5·22
Section 6 Specifications
6.1 Tape Transport . .. .............. ............ ..................... .... .. ................................. .. ..... 6·1
6.2 Electronics ........ ............... ............. ......... . ............. .. ................. .. .......... .. .... ...... . 6· 2
6.3
Physical .......... ............ ....................... ........ .. .................. .. ........................... ... . 6· 4
6.4 Accessories .......... .... ..... .... ........ .... ....... ...... ...... ........ ............. .. ........................ 6· 4
Section 7 Exploded Views and Parts Lists
7.1 General .. .. .......... .............. ...................................... . ........................ .. ................ 7·1
7.2 Parts Lists ............................................... .. .. .... .... ...... ........................ .. .. .. .. ... ... 7·1
Section 8 Printed Circuit Board Layouts and Parts Lists
8.1 General ...... ... ............................ ..... ....................... ........ ...... .. ................. ......... 8·1
8.2 Parts Lists ............ ...... .. ........ ... ...... .... .. ..................... .... ........ ..... ... ........... 8-1
Recommended To ols
Schematics
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MX-55 Operation and Maintenance Manual
List of Figures
Figure 2-1 Tape Transport . .... ... .. .. ............... . ...... . ...... . ..... . .... . .... ... .. .. ..... .... ..... 2 ·1
2-2 Transport Control Panel .. .... ... ......... ..... . .. .. ................ .. ... .............. 2·4
2-3 Head Assembly ....... .. ....... ............... .... ....... .. .. .......... .. .... . ........... .2 ·12
2-4 Amplifier Panel ...... .. ........................... ............. . .. ..... ..... .. .... .. ..... .2 -13
2-5 Amplifier Connector Panel .. .. ...... ..... ....... ................. .. .... ........ .... 2 ·19
2-6 Transport Connector Panel .... .......... ........................... ....... .. .. .... 2·21
2-7 Controls on the Audio Amplifier PCB Assembly ........ .. .. .......... .2- 23
2-8 Controls on the Mic Amplifier PCB Assembly ................... ...... 2·24
2-9 Controls on the Mother Board PCB Assembly .. . .... .... .... .. .. .. .. . 2·25
Figure 3-1 Reel Spindle ... .. ................ ... ..... .. .... .. . ........ ... ........... .... .. ........... ..... 3·1
3-2 Mounting the Reel Table .... .. . .. ................. .. ... .. ...... .... .... ............... 3·1
3-3 Mounting the AEG (DIN) Hub Adapter .......... .... .... ........ ... .. ........ 3-1
3-4 Tape Threading ........ . .. .... .. ...... . .... ......... ..... .... ...... .......... .. .. .. . ........ 3·2
3-5 Editing the TApe .. ....... .. .......... ............ ..... .... .......... .. ... . .. ..... ......... 3 ·15
Figure 4·1 Demagnetizing the Heads .... ... ........ ................ ... .. . ...... ...... . .. ........ 4·2
4-2 Cleaning the Heads .. .. .... .. . ............ .... .. .. .......................... ....... .... ... 4·3
4-3 Capstan M oto r Bearing Lub rication .... ........................... .... ...... .. 4·4
4-5 H ead He ight and Zenith Adjustment .... .... ... .... ...... .. .. ... .. ... ...... .. .. 4 - 7
4-6 Wear Patterns ...... ........... ...... ..... .. .................... .... .......... .. .... .. ...... 4·7
4-7 Measuring Reel Table Height ..... .. .... .. .... .. ........ .. ............ ...... ....... 4·8
4-8 Reel Table Adjustment ..... ... . ...... .. ......... . ........ ......... ..... .. .. .. .......... 4·9
4-9 Reel Brake Tension Measurements ........... .......... .. .. ............. . .. .4 -10
4-10 Reel Brake Adjustment ...... .. .............. ..... .. ... .................. ....... .. . ... 4 -11
4-11 Pinch Roller Pressure Measurement .... ... .. .. .. .... .. ....... .. .. ...... .... 4 -12
4-12 Pinch Roller Pr es sure Adjustment ....... .. .. . ...... .. .. .... .. .. ...... .... ... 4·13
4-13 Tape Lifter Clearance Measurement ........ ........................ ....... .. 4 ·14
4-14 Tape Lifter Adjustment .... .... ........... ........... . .. .. ...... ..... .... ...... ..... ..4 ·14
4-15 Controls on the Transpo rt Control PCB Assembly .. .... ............ 4 ·15
4-16 Capstan Waveform Display ... .. ....... ....... ........................ ........... .4 -15
4-17 Capstan Servo Block Diagram ....... ..... ... .. .. ............ .. .. ...... .... .. ... 4 -16
4-18 Audio Amplifier Block Diagram ...... .. . ... ........ .. ..................... ...... 4 ·18
4-19 Location of Trimmers on Audio Amplifier PCB Assembly .... .4 -19
4-20 Test Oscillator Waveform .... . .......... ..... ........ .... .. .......... ............. .. 4 - 20
4-21 Azim uth Test Set-Up ...... .. ............ . .. .. ...... ............... .... .... .. .. ...... .. 4 - 23
4-22 Azimuth Adjustment Screws ...... .. .. .............. .. .... .... .. .. ............... 4 - 23
4-23 Azimuth Adjustment Displays .. .... .. .......................... ... .......... .... 4 - 23
4-24 Location of Trimmers on Audio Amplifier PCB Assembly ... 4·24
4-25 Adjustment Points and Amplitude Adjustment ............ .. .... .... . .. 4·27
4-26 Re cord Azimuth Adjustment Set-Up ... .. ......... ... ....... .. ..... .. . .. .... 4 - 29
4-27 Re c ord Head Azimuth Oscilloscope Display ..... .. ... .. .... ...... ...... 4 - 30
Figure 5-1 Opening the Amp Top Panel .. ... . ........ ........ .. ........... ...... ....... ........ 5 - 3
5-2 Opening the Transport Rear Panel .. ............ .. .. .. .. .. ... . ............ ...... 5·4
5-3 Pin Assignment of Power Connector ......... .... .. ........ .. ............ .... 5·7
5-4 Voltage Select Wiring ........ ............. .... .... . ......... .... .... .... .... .. ...... .... 5 - 7
5-5 Audio Connector Wiring .. .. ..... .... .. .. ........ .. ... ...... ... ...................... .5 - 8
5·6 Connection of the Machines .... .. ........ .. ................... .... . .. .. .. ........ 5 -10
5-7 Installing Rear Legs ............ ...... . ........ . .. . .. .......... ......... .. ............. 5 -14
5-8 Mounting the ZA-SCG Rack Adapter .............. .. .... . .... .... .. .... ..... 5 -14
5-9 Mounting Hole Spacing .. .. ........ ...... ........ .... .... ... .... ......... .... .... ... 5 -14
5-10 Assembling the ZA-81 B- T Pedestal ....... .. . .. ... . ........ . .. .. .... ...... ... 5 ·15
5-11 Assembling the ZA-81 B- T Pedestal with Spacer .. ... .......... ..... 5 ·16
4-4 Head Posi tion Ad jus tment Screws ...... .... .. ............... ......... .. .. ..... 4-7
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MX-55 Operation and Maintenance Manual Table of Contents
Figure 5-12 Assembling the ZA-81C-S Pedestal .... .. . .. .... .......... . .. .. . .. .. ..... .... 5-17
5-13 Opening the Amp Panel ........ .. ...... .............. .... ...... ...... ...... .. .... ... 5 -18
5-14 Mounting the Input/Output Transformer PCB ...... ...... .. .... ...... .5 -19
5-15 Wiring of the Transformers ........ .... ........ .. ...... .... .... .... .. ...... .. ..... 5 -19
5-16 Mounting the VEM PCB .... .... .. .... ...... ...... ........ .. .... ...... .... ...... .. .. .5 - 21
5-17 Mounting Foot Switch Jack/Fader Control Connector .. .... ...... 5 - 22
5-18 Mounting the Proximity Sensor .. ........ .... ........ .. ........ .. .... ...... .... 5 - 22
List of Tables
Table 1-1 MX-55 Series Machine Configurations ........... .... ...... .. .... ......... . 1 -1
Table 4-1 Recommended Overbias .. .... .. . .... .... .. .... .... ...... ........... .... ...... .. .. 4 - 28
Table 5-1 Standard Accessories .... .. ...... .. .... .... ................ .... ...... ........ ........ . 5-1
5-2 DIP Switch Positions ................ . .. ...... ......... .... ............ .... .... .... .. .. 5 - 5
5-3 PARALLEL I/O Connector Pin ASSignment .. ........ .. .... . ........ ..... 5 - 9
November 1989 xiii

MX-55 Operation and Maintenance Manual
Introduction
Section 1
Introduction
The Otari MX-55 Series Tape Recorders are compact high-perfor-
mance 1/4" tape recorder/reproducers utilizing the latest technology
in analog tape recording . The MX-55 Series is comprised of six
machines in the following configurations.
Table 1-1
MX-55 Series Machine Configurations
Model Track Configuration
Cabinet Style
MX-55N NAB 2trk 2ch
Standard
MX-55N-M
NAB 2trk 2ch
Meterbridge
MX-55D
DIN Stereo Standard
MX-55DE
DIN Stereo Standard (Euro version)
MX-55T
NAB 2trk 2ch with center time code track Standard
MX-55T-M
NAB 2trk 2ch with center time code track
Meterbridge
This manual is intended for use with MX-55T-M, MX-55T and MX-
55N-M models.
1.1 MX-55 Series Tape Recorders
The MX-55 Series of Tape Recorders are built on die-cast aluminum
alloy deck plates and side frames for maximum ruggedness and
mechanical stability.
All machines in the series will accept any size reel from a 5" EIA reel
to an 11.8" DIN hub. Different size reels can be used for Supply and
Take-up.
The front panel pitch control utilizes a unique rotary encoder to pro-
vide ±20% variable speed range in 0.01 % increments. The capstan
motor speed can also be controlled by an external source of 9600
Hz (nominal) square waves for easy interface with a synchronizer or
similar controller. The speed range under external control is
+ 100%, -50%.
An optional Voice Edit mode PCB allows listening at twice normal
play speed without pitch shift for easy editing of lecture and inter-
view work or for transcription.
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1-1

Introduction
MX-55 Operation and Maintenance Manual
The built-in tape timer displays the current tape position as Hours ,
Minutes and Seconds, or the tape speed in inches per second, or
the tape speed as a percentage of change from the selected play
speed.
The tape timer incorporates a four point search-to-cue locator with
three cue point memor ies and a zero location memory. The includ-
ed repeat function allows continuous repeat play between any two
selected cue pOints. One cue point memory can be set to store the
location where Play or Record was last entered, for easy return to
the beginning of a sequence or take.
All machines in the Series feature front panel selection of two oper-
ating speeds, with internal switch selection of either High (15 ips
and 7.5 ips) or Low (7.5 ips and 3.75 ips) speed pair operat , ion.
The MX-55 Series ma chines provide switc h selection of NAB or lEG
equalization; +4 dBm or -16 dBm Input and Output levels; 185, 250
or 370 n Wb /m Reference Fl ux level with front panel indication of
Reference Flux lev el and eq ualization. XL type connectors are pro-
vided for Inputs and Outpu ts with transformerless active balanced
Circuit ry.
The MX-55 Ser ies mach ine s also provide the HX Pro· Headroom
Extension System. HX Pro improves the high frequency perfor-
mance of any tape recorded on the MX-55 by analyzing the high fre-
quency components of th e au dio signal and continuously adjusting
recording bias to mai nta in bias linearity for optimum distorUon,
noise, and frequency response characteristics. HX Pro is not an
"encoding" process, and does not require any decoding during
playback.
* Dolby HX Pro : HX Pro Headroom Extension originated by Bang & Olufsen
and manufactured under license from Dolby Licensing Corporation. UDolby"
and the Double-D symbols are trademarks of Dolby Li censi ng Corporation.
1 - 2
November 1989

MX-55 Operation and Maintenance Manual
Introduction
1.2 Using This Manual
This manual is intended for use with MX-55T-M, MX-55T and MX-
55N-M model. For convenience, the descriptions and references
apply to MX-55T-M, where any differences exist between this model
and others in the series, those differences will be fully explained in
context.
1.2.1 Organization
This manual is divided into nine sections beginning with this INIRO-
DUCTION which contains general information about the MX-55
Series and about the manual.
Section 2, CONTROLS AND INDICATORS, contains a keyed reference
guide to the operating controls, indicators and connectors on the
machine. This section contains detailed information about each
control and its function. Refer to this section when you have a
question about the function of a particular control, indicator, or con-
nector.
Section 3, OPERATION describes the operation of the MX-55
machines, and is divided into two parts;
a. A table of machine operating modes, which lists each mode and
the controls necessary to enter that mode; and
b. Detailed operating instructions, which describe each operation
and the controls and indicators associated with that operation.
Section 4, MAINIENANCE AND ADJUSTMENT, provides the infor-
mation necessary to perform routine maintenance operations,
including head cleaning and demagnetizing and capstan motor
lubrication. It also covers the audio and transport adjustments
associated with normal operation of the machine.
Section 5, INSTALLATION, contains the information necessary when
first unpacking and installing the machine. The information and
procedures contained in this section should be followed very care-
fully when the machine is first unpacked and installed. Performing
the inspection and checkout steps will familiarize you with the
machine and its component parts if this is your first contact with
the MX-55 series of tape recorders.
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Introduction
MX-55 Operation and Maintenance Manual
Section 6 lists the SPECIFICATIONS of the MX-55T-M, MX-55T and
MX-55N -M tape recorders.
Section 7, EXPLODED VIEWS AND PARTS USTS, contains assembly
drawings of the machine "exploded" to show internal parts and
hardware, and the order of assembly. Each drawing is keyed to an
accompanying Parts List containing the Otari part number for each
mechanica 'l component.
Section 8, PRINTED CIRCUIT BOARD LAYOUTS AND PARTS USTS,
contains two-color "X-ray" views of the printed circuit boards
(PCBs) showirilg component locations and foil traces. This section
also contains Parts Lists of the e' lectronic components associated
with each PC'S.
The final section contains the SCHEMATIC DIAGRAMS for all elec-
tronics assemblies and pr i rlted circuit boards.
1.2.2 Conventions within this manual
Generally this manual uses all capital letters to describe a control,
indicator, or connector when that item is similarly labeled on the
mach.ine (e.g., INPUT level control or PARALLEL lID connector).
Where a control or indicator is not labeled on the machine, the
name of that item , is spelled with initial cap ' italletters only (e.g., Mic
Input connector or Cue Spea ' ker). The six major transport control
buttons are not labeled on the machine, but are labeled on the but-
ton caps with graphic symbols. Th l is manual uses the name of the
button rather than the graphic symbol whenever the buttons are ref-
erenced.
BuHonSynoi
Name
PLAY
RECORD
STOP
FAST FORWARD (F. FWD)
REWIND
CUE
1 ·4
November 1989