Otari MX-50II Operating and Maintenance Manual

Part No. OS3-322

R

MX-50II

PROFESSIONAL TAPE RECORDER

OPERATION AND MAINTENANCE MANUAL

FIFTH EDITION

Printed: June 1996

Ed 5 (GK)

Copyright © 1991, 1992, 1993, 1994, 1996 by Otari, Inc.

Printed in Japan

This manual may not be reproduced by any means without written permission.

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.

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.

		SAFETY INSTRUCTIONS
1.	Read Instructions	All safety and operating instructions should be read before the device is
		operated.
2.	Retain Instructions	The safety and operating instructions should be retained for future reference.
3.	Heed Warnings	All warnings on the device and in the operating instructions should be
		complied with.
4.	Follow Instructions	All operating and use instructions should be followed.
5.	Water and Moisture	The device should not be used near water — for example, near a bathtub,
		wash bowl, sink, laundry tub, in a wet basement, near a swimming pool, etc.
6.	Carts and Stands	The device should be used only with a cart or stand that is recommended by
		the manufacturer.
7.	Ventilation	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.
8.	Heat	The device should be situated away from heat sources such as a radiator,
		heat register, stove or other appliances (including amplifiers) that produce
		heat.
9.	Power Sources	The device should be connected to a power supply only of the type described
		in the operating instructions or as marked on the device.
10.	Grounding or Polarization	Precautions should be taken so that the grounding or polarization means of
		the device is not defeated.
11.	Power Cord Protection	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.
12.	Cleaning	The device should be cleaned only as recommended by the manufacturer.
13.	Non-Use Periods	The power cord of the device should be unplugged from the out-let when left
		unused for a long period of time.
14	Object and Liquid Entry	Care should be taken that objects do not enter and that liquids are not spilled
		into the enclosure through openings.
15.	Damage Requiring Service	The device should be serviced by qualified service personnel when:
		A. The power supply cord or the plug has been damaged; or
		B. Objects have entered, or liquid has been spilled into the appliance; or
		C. The appliance has been exposed to rain; or
		D. The appliance does not appear to operate normally or exhibits marked
		change in performance; or
		E. The appliance has been dropped, or the enclosure damaged.
16.	Servicing	The user should not attempt to service the device beyond that described in
		the operating instructions. All other service should be referred to qualified
		personnel.

COMMUNICATION WITH OTARI

FOR SERVICE INFORMATION AND PARTS

All Otari products are manufactured under strict quality control. 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 Otari dealer or contact Otari at:

Otari, Inc.		Otari Corporation
4-33-3 Kokuryo-cho		378 Vintage Park Drive
Chofu-shi, Tokyo182		Foster City
Japan		California 94404
		U.S.A.
Phone	: (0424) 81-8626	Phone	: [phone]
Telex	: J26604 OTRDENKI	Telex	: 650 302 8432 MCI UW
Fax	: (0424) 81-8633	Fax	: [phone]
Cable	: OTARIDENKI TOKYO

Otari Deutschland GmbH.			Otari Singapore Pte., Ltd
Rudolf-Diesel-Str.12			40 MacTaggart Road
D-40670 Meerbusch 2 (Osterath)			Singapore 1336
F.R.Germany			Phone	: (65) 284-7211
Phone	: (02159)	50861	Telex	: RS 36935 OTARI
Telex	: 8531638 OTEL D		Fax	: (65) 284-4727
Fax	: (02159)	1778

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.

January 1994

Table of Contents

Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

Communication with Otari . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Section 1 Introduction

1.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.2 Using this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

1.3 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

1.3.1 Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

1.3.2 Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

1.3.3 Physical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

1.3.4 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

Section 2 Installation

2.1 Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

2.2 Connecting the MX-50II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Section 3 Controls and Indicators

3.1	Transport Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-2
3.2	Connector Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3-8

Section 4 Operation

4.1	Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		4-2
4.2	Mounting the Reels and Threading the MX-50II . . . . . . . . . . . . . . . . .		4-3
	4.2.1	Placing the Reels on the Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-3
	4.2.2	Threading the Tape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-4
4.3	Transport Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		4-5
4.4	Audio Channel Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		4-6
4.5	Locator Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		4-6
4.6	Vari Speed Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		4-7
4.7	Voice Edit Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		4-7

Section 5 Maintenance and Adjustment

5.1 Routine Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5-2
5.1.1	Demagnetizing the Heads and Tape Path . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5-2
5.1.2	Cleaning the Heads and Tape Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5-3
5.1.3	Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5-3

5.2 Transport Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

5.2.1 Head Position Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

5.2.2 Reel Table Height Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

May 1991

viii

Table of Contents		MX-50II Operation and Maintenance Manual
5.2.3	Reel Brake Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. 5-5
5.2.4	Tape Lifter Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5-6
5.2.5	Pinch Roller Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5-6
5.2.6	Capstan Motor Servo Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5-7
5.3 Audio Channel Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			5-8
5.3.1	Input/Output Level and Peak Indicator Level Adjustments . . . . . . . . . . . .		5-9
5.3.2	Reproduce Electronics Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5-10
	5.3.2.1	Reproduce Head Azimuth Adjustment . . . . . . . . . . . . . . . . . . . . . . .	5-10
	5.3.2.2	Reproduce Level Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5-11
	5.3.2.3	Reproduce Equalization Adjustment . . . . . . . . . . . . . . . . . . . . . . . . .	5-11
5.3.3	Record Electronics Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5-12
	5.3.3.1	Record Bias Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5-12
	5.3.3.2	Record Head Azimuth Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . .	5-12
	5.3.3.3	Record Level Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5-13
	5.3.3.4	Record Equalization Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5-13
	5.3.3.5	Low Frequency Reproduce Equalization Adjustment . . . . . . . . .	5-14
	5.3.3.6	Bias Oscillator Transformer Dummy Load Adjustment . . . . . . .	5-14

Section 6 Printed Circuit Board Layouts and Parts Lists

6.1 Control PCB Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

6.2 Audio Amplifier PCB Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-7

Section 7 Exploded View Drawings and Parts Lists

7.1	Case Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7-2
7.2	Head Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7-4
7.3	Reel Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7-6
7.4	Transport Assembly (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7-8
7.5	Transport Assembly (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7-10
7.6	Transport Assembly (3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7-12
7.7	Amplifier and Connector Panel Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . .	7-14

Appendix: Optional Accessory Installation Procedure

A: Rack Mount Kit (ZA-5EK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AP-2

B: Pedestal (Stand) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AP-3

C: Input and Output Transformers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AP-4

D: VEM (Voice Edit Mode) PCB Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AP-6

E: Low Speed Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AP-7

Circuit Diagrams

Index

ix

May 1991

Section 1 Introduction

This section contains general information about the MX-50II two channel analog tape recorder and about this manual.

1.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.2 Using this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

1.3 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

1.3.1 Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

1.3.2 Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

1.3.3 Physical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

1.3.4 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

May 1991

1 - 1

Section 1 Introduction

MX-50II Operation and Maintenance Manual

1.1 General

Table 1-1

MX-50II Series Machine Configurations

The Otari MX-50II series tape recorders are economical high-performance 1/4" tape recorder/reproducers utilizing the latest technology in analog tape recording. The MX-50II series recorder/reproducers are comprised of two machines in the following configurations.

_______________________________

Model	Track Configuration
_______________________________
MX-50II-N	NAB 2 track 2 channel
MX-50II-D	DIN Stereo

_______________________________

Main Features:

All machines in the series will accept any size reel from a 5" EIA reel to an 11.2" DIN reel. Different size reels can be used for supply and take-up.

The front panel pitch control provides ±8% variable speed range. 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 -50– +100%.

An optional VOICE EDIT MODE PCB assembly allows listening at twice normal play speed without pitch shift for easy editing of lecture and interview work or for transcription.

For convenience of tape editing work, the monitor speaker unit and headphone connector with channel selector switches are equipped.

The built-in tape timer displays the current tape position as Hours, Minutes and Seconds. The tape timer incorporates a search-to-cue locator with one cue point memory and a zero location memory.

All machines in the series feature front panel selection of two operating 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 operation.

The MX-50II series machines provide switch selection of NAB or IEC equalization with front panel indication of equalization. XL type connectors are provided for inputs and outputs.

1 - 2

May 1991

MX-50II Operation and Maintenance Manual

Section 1 Introduction

1.2 Using this Manual

Button Symbol			Name
			PLAY
			RECORD
			STOP
			FAST FORWARD (F.FWD)
			REWIND
			CUE

This manual is intended for use with both MX-50II models. For convenience, the descriptions and references apply to the MX-50II-N, where any differences exist between this model and others in the series, those differences will be fully explained in context.

Organization: This manual is divided into nine sections beginning with this Introduction which contains general information about the MX-50II Series and about the manual.

Section 2, Installation, contains the information necessary when first unpacking and installing the machine. The information and procedures contained in this section should be followed very carefully when the machine is first unpacked and installed.

Section 3, 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 connector.

Section 4, Operation, describes the operation of the MX-50 machines, and is divided into two parts; a. A table of machine operating modes listing 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 5, Maintenance and Alignment, provides the information 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 6 Printed Circuit Board Layouts and Parts Lists, contains two-color “x-ray” views of the printed circuit boards (PCBs) showing component locations and foil traces. This section also contains Parts Lists of the electronic components associated with each PCB.

Section 7 Exploded Views and Parts Lists, 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 mechanical component.

Appendix contains the installation instruction for optional accessories.

The final section contains the Schematic Diagrams for electronics assemblies and major printed circuit boards.

Conventions within this Manual

This manual uses the following notation:

Buttons, Switches	PLAY BUTTON or TAPE TIMER
Indicators, LED lamps	READY INDICATOR
Modes	PLAY or PLAY MODE

The six major transport control buttons are not labeled on the machine, but are labeled on the button caps with graphic symbols. This manual uses the name of the button rather than the graphic symbol whenever the buttons are referred.

May 1991

1 - 3

Section 1 Introduction				MX-50II Operation and Maintenance Manual
1.3 Specifications
1.3.1	Transport
Track Configuration	1/4" (6.3 mm), 2 track
Heads	Erase x 1
	Record x 1
	Reproduce x 1
Motors	Capstan x 1 Quartz PLL Servo Controlled Direct Drive Brushless DC Motor
	Reel x 2	AC Induction Motor
Reel Size	Max. 11.2" (DIN)
Tape Speeds	High speed version		15 and 7.5 ips (38.1 and 19.05 cm/s)
	Low speed version*		7.5 and 3.75 ips (19.05 and 9.5 cm/s) *manufactured to order
Tape Speed Accuracy	Max. ±0.2%
Tape Speed Deviation	Max. 0.2%
Vari Speed	±8%
VEM Tape Speed	+100% with optional VEM accessory, at 7.5 ips and 3.75 ips only.
Wow and Flutter (Peak Weighted DIN 45507)	15 ips	Max. ±0.06%
	7.5 ips	Max. ±0.08%
	3.75 ips	Max. ±0.12%
Start Time*	15 ips	Max. 0.4 s		*Time required to accelerate
	7.5 ips	Max. 0.3 s		to double the specified Wow and Flutter value
	3.75 ips	Max. 0.25 s
Stop Time	15 ips	Max. 0.5 s
	7.5 ips	Max. 0.4 s
	3.75 ips	Max 0.4 s
Fast Wind Time	60 Hz	100 s for 2,500 ft
	50 Hz	120 s for 2,500 ft
1.3.2	Electronics
	NOTE: All specifications are measured with AMPEX #456.
Line Input	Mode		Transformerless Active Balanced
	Input Impedance		10 kΩ
	Nominal Level		+4 dBu (MX-50II-N)
			+6 dBu (MX-50II-D)
	Max. Level		+30 dBu
	Connector		XL type
Line Output	Mode		Transformerless Single End
	Output Impedance		Min. 5 Ω
	Nominal Level		+4 dBu (MX-50II-N)
			+6 dBu (MX-50II-D)
	Max. Level		+22 dBu
	Connector		XL type (Male)
Phone Output	Load Impedance		Min. 8 Ω
	Connector		1/4" (6 mm) Stereo Phone Jack

1 - 4

May 1991

MX-50II Operation and Maintenance Manual					Section 1 Introduction
Equalization	NAB/IEC switchable
Reference Fluxivity	250 nWb/m (185 – 510 nWb/m adjustable)
Frequency Response (Overall)	15 ips	30 Hz – 20 kHz ± 2 dB (SRL)			[MX-50II-D SRL -20 dB]
MX-50II-N: SRL = 250 nWb/m	7.5 ips	30 Hz – 18 kHz ± 2 dB (SRL -10 dB)			[MX-50II-D SRL -20 dB]
MX-50II-D: SRL = 510 nWb/m	3.75 ips	20 Hz – 10 kHz ± 2 dB (SRL -20 dB)			[MX-50II-D SRL -20 dB]
Signal to Noise Ratio	Unweighted with audio filter (30 Hz – 18 kHz)
		NAB	IEC	Recording Level
MX-50II-N	15 ips	Min. 69 dB	Min. 70 dB	1040 nWb/m
	7.5 ips	Min. 71 dB	Min. 67 dB	1040 nWb/m
	3.75 ips	Min. 64 dB	Min. 67 dB	740 nWb/m
MX-50II-D	15 ips	Min. 69 dB	Min. 70 dB	1040 nWb/m
	7.5 ips	Min. 66 dB	Min. 67 dB	1040 nWb/m
	3.75 ips	Min. 62 dB	Min. 63 dB	740 nWb/m
Distortion (THD)	Max. 0.3% (MX-50II-N: 1 kHz, 250 nWb/m, 15 ips, Rec/Rep)
	Max. 0.7% (MX-50II-D: 1 kHz, 510 nWb/m, 15 ips, Rec/Rep)
Crosstalk	Min. 55 dB (MX-50II-N: 1 kHz)
	Min. 50 dB (MX-50II-D: 1 kHz)
Depth of Erasure	Min. 75 dB (MX-50II-N: 1 kHz, 1040 nWb/m, 15 ips)
	Min. 70 dB (MX-50II-D: 1 kHz, 1040 nWb/m, 15 ips)
Bias and Erase Frequency	150 kHz ±10 kHz

1.3.3

Physical

Power Requirements

100/117/220/240 Volts ±10% single phase AC, 50 or 60 Hz

Power Consumption

100 VA

Operating Environment

5°–40°C, 20–80% RH

Storage Environment

-20°–45°C, 10–80% RH

Weight

25 kg (55 lbs)

Dimensions (W x D x H)

430 x 455 x 250mm (16.9" x 7.3" x 17.1")

430

186

28

450

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Section 1 Introduction

MX-50II Operation and Maintenance Manual

1.3.4	Accessories
Standard Accessory	NAB Hub Reel Hold Down Knob	2 pcs
	Power Cable	1 pc
	Fuse 2A	1 pc
	Fuse 3A	1 pc
	Fuse 4A	1 pc
	Fuse 5A	1 pc
	Time Lag Fuse	2 pcs
	Lubrication Oil	1 pc
	Operation Manual	1 pc
Optional Accessory	Transport Remote Control Unit	CB-127-S
	Mono Head Kit	KH-43X-S
	Scissors	SB-12X
	Scissors (Reverse cut angle)	SB-13D-S
	10.5" NAB Reel	ZA-51A
	11.2" DIN Reel	ZA-5EG
	Rack Mount 19" Rack Adapter	ZA-5EK
	VEM Unit	ZA-5EL
	Pedestal (Stand)	ZA-5ET
	Input Transformer	ZA-5EY
	Output Transformer	ZA-5EZ
	Proximity Sensor	SR-21F-S

1 pc for MX-50II-N PZ9E003 OS3-322

CB-127

for MX-50II-D for MX-50II-D

Otari reserves the right to change specifications without notice or obligation.

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January 1992

Section 2 Installation

This section contains the necessary information for unpacking, inspecting, and installing the MX-50II, and includes procedures for customizing the MX50II.

2.1 Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

2.2 Connecting the MX-50II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

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Section 2 Installation

MX-50II Operation and Maintenance Manual

2.1Unpacking and Inspection

Uncrating the Machine: We recommend that you open the carton carefully and retain the packing materials at least until proper operation of the machine has been established.

When sending the machine back to Otari or to your Otari dealer, follow the packing instructions printed on the carton.

CAUTION: The MX-50II weighs approximately 25 kg (55 lb.). Although uncrating and installation can be done by one person, it is recommended that you do these procedures with another person.

The carton contains the following standard accessories:

Table 2-1

Standard Accessories

REAR COVER

CONTROL PCB ASSY

_________________________________________________________________

Item	Part No.	Q'ty	Notes
_________________________________________________________________
Reel Clamper	KW0HV	1 set
Power Cord	PZ9D003	1	for MX-50II-N
Power Cord	PZ9D229	1	for MX-50II-D
Time Lag Fuse	FH9-018	1
Time Lag Fuse 3.15A	FH9-020	1	for MX-50II-D
Fuse 2A	FH7F020	1	5 x 20 mm
Fuse 3A	FH7F030	1	5 x 20 mm
Fuse 4A	FH7F040	1	5 x 20 mm
Fuse 5A	FH7F050	1	5 x 20 mm
Lubrication Oil	PZ9E003	1	for capstan motor bearing
Operation Manual	OS3--322	1
M4 x 6 Screw	———	4	for re-attaching bottom cover after removing bottom feet

_________________________________________________________________

Inspection: Before making any electrical connections, inspect the machine visually. If there is any evidence of damage due to rough handling during transportation, a claim should be filed with the transportation company. Do not connect or operate the MX-50II until the inspection has been completed, and any damage identified and corrected if necessary.

Customizing your MX-50II: Some of the operating methods can be changed according to your preferences.

1.Remove the rear cover by removing the four screws on the top of the machine, the upper rear feet, and the two screws above the slanted portion of the rear cover. Refer to Figure 2-1.

2.Loosen the two screws at the top of CONTROL PCB ASSEMBLY and hinge it down to horizontal.

3.Change the settings of the DIP switch on CONTROL PCB ASSEMBLY if necessary. Refer to Table 2-2.

Figure 2-1

Opening the Transport Rear Cover

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June 1996

MX-50II Operation and Maintenance Manual			Section 2 Installation
Table 2-2
DIP Switch Functions	________________________________________________________________
	Switch	Function	Factory Setting
	________________________________________________________________
	SW1-1	Punch In (How to enter RECORD mode)	off
	ON	Press RECORD when in PLAY MODE.
	off	While Holding RECORD down, press PLAY.
	SW1-2	Punch Out (How to leave RECORD without stopping the transport)	off
	ON	Press PLAY.
	off	While holding RECORD down, press STOP.
	SW1-3	Speed Pair Selection	off
	ON	Low Speed Pair = 7.5 and 3.75 ips.
	off	High Speed Pair = 15 and 7.5 ips.
	SW1-4	Vari Speed During Record mode.	ON
	ON	EXT and VARI SPEED MODES cannot be entered during RECORD MODE.
	off	EXT and VARI SPEED MODES can be entered while in RECORD MODE.
	SW2	Fader Control Logic Level Selection (MX-50II-D Only)	M
	M	Make (Normally open) contact closure, or logic level active low.
	B	Brake (Normally closed) contact closure, or logic level active high.
	________________________________________________________________

NOTE: Turn off the power to the MX-50II whenever changing the setting of SW1 or SW2. The change of setting does not take effect until the power is turned back on.

Please refer to Appendix for more information about operating the MX-50II at 3.75 ips.

2.2Connecting the MX-50II

Power Connection: Insure that the voltage and frequency supplied to the machine agree with the machine's power requirement printed on the label on the connector panel or on the carton. Make sure that the MX-50II POWER

AC		AC
HOT	GND	NEUTRAL

Figure 2-2

switch is turned off then connect the supplied power cord from the AC mains to the machine.

Power Connector Pin Assignment

Connecting the Audio Signal: The audio inputs to the MX-50II are balanced. The outputs are unbalanced.

BALANCED INPUT		2
2	1 GND	1
COLD
	3	3
	HOT

UNBALANCED OUTPUT 1

GND

1

2

2

3

3

Figure 2-3

Audio Connector Wiring (MX-50II-N)

INPUT CONNECTORS of the MX-50II-N are wired as follows:

Pin 1 = Shield (GND), Pin 2 = Cold, Pin 3 = Hot.

OUTPUT CONNECTORS of the MX-50II-N are wired as follows:

Pin 1 = GND, Pin 2 = GND, Pin 3 = Hot.

INPUT CONNECTORS of the MX-50II-D are wired as follows:

Pin 1 = Shield (GND), Pin 2 = Hot, Pin 3 = Cold.

OUTPUT CONNECTORS of the MX-50II-D are wired as follows: Pin 1 = GND, Pin 2 = Hot, Pin 3 = GND.

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Section 2 Installation

MX-50II Operation and Maintenance Manual

Connector Pin Assignments

Table 2-3

REMOTE Connector Pin Assignment

_______________________________ ________________________________

No.	Description		Level	I/O		No.	Description	Level	I/O
_______________________________						________________________________
1.	RECORD Switch		Low	In		20.	Capstan Spd Control Clock (*2)	—	In
2.	PLAY Switch		Low	In		21.	Tape Speed A (*3)	H/L	Out
3.	STOP Switch		Low	In		22.	Tape Speed B (*3)	H/L	Out
4.	F.FWD Switch		Low	In		23.	External Pitch Control Enable	Low	In
5.	REWIND Switch		Low	In		24.	NC	—	—
6.	Lifter Switch		Low	In		25.	NC	—	—
7.	NC		—	—		26.	NC	—	—
8.	NC		—	—		27.	NC	—	—
9.	Safety Switch Shut off		Low	Out		28.	NC	—	—
10.	Record Mode Tally		Low	Out		29.	NC	—	—
11.	Play Mode Tally		Low	Out		30.	NC	—	—
12.	Stop Mode Tally		Low	Out		31.	NC	—	—
13.	F.FWD Mode Tally		Low	Out		32.	NC	—	—
14.	REWIND Tally		Low	Out		33.	+5V ±10% Reg. Power Supply (max 150 mA)
15.	NC		—	—		34.	24–40V Unreg. Power Supply (max 500 mA)
16.	Signal Ground					35.	24–40V Unreg. Power Supply (max 500 mA)
17.	Tach. Pulse (*1, 9)			Out		36.	Power Ground
18.	Tape Direction (Fwd=Low)		H/L	Out		37.	Power Ground
19.	NC		—	—		________________________________
_______________________________
NOTES: 1		Tach Pulse Rate (pulse/s)	3.75 ips = 30,			7.5 ips = 60, 15 ips = 120
	2	Capstan Control Freq.	9.6 kHz = nominal tape speed.
			Acceptable external frequency range = 4.8–19.2 kHz
	3	Tape Speed Definition	3.75 ips		Speed A = Low,		Speed B = Low
			7.5 ips		Speed A = Low,		Speed B = High
			15 ips		Speed A = High,		Speed B = Low
	4	Connector Type	D-sub 37 pin (female)
	5	Output Signals	Output Type = Open Collector
			VOL = 0–0.5 V,			IOL = 20 mA (max), VIL = TTL Level
			Leakage Current = 20 µ A
			Pull Up = 10 kΩ (terminated to +5 V)
			VOH (High Level) = +30 V (max)
	6	Input Signals	Fan-in = 1.5
			VIL = 0–0.5 V (2.4 mA),				VIH = 2.5–5.25 V (60 µ A)
	7	Cable Length:	max 10 m (32 feet)
	8	Input Command Pulse:	100 ms (min)
	9	Tach Pulse:	50 µ s (min)
	10 Capstan Clock Duty Cycle:		40–60%

Table 2-4

FADER Connector Pin Assignment (Only MX-50II-D models)

____________________________

No.	Description	I/O
____________________________
1.	Fader Play Switch	In
3.	Repro Contact*	Out
6.	Signal Ground	—
8.	Repro Contact*	Out
9.	Frame Ground	—

____________________________

NOTE: To enter PLAY, connect pin 1 to pin 6. Pins 3 and 8 are closed when in REPRO MODE.

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May 1991

Section 3 Controls and Indicators

This section describes the controls, indicators, and connectors on the MX50II tape recorders.

3.1 Transport Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

3.2 Connector Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8

May 1991

3 - 1

Section 3 Controls and Indicators

MX-50II Operation and Maintenance Manual

3.1 Transport Control Panel

POWER

1

MONITOR

2

1

3

2

PHONES

4

Figure 3-1

Transport Control Panel — 1

[1]POWER SWITCH

[2]MONITOR LEVEL KNOB

[3] MONITOR CHANNEL SELECT BUTTONS

[4] PHONES CONNECTOR

FIX VARI EXT VEM

DOWN

UP

				5
		1						2
20 10	6	3	10	1	PEAK	20 10	6	3	10	1	PEAK
					2 3						2 3
		VU						VU			NAB
											IEC

H

INPUT	INPUT
	SRL			FADER
	1	READY	2	TAPE
		SAFE		INPUT
OUTPUT	OUTPUT
	SRL

6

7

6

8

9

Pressing the upper portion of this switch causes power to be applied to the machine.

This control adjusts the level of the signal at PHONES CONNECTOR [4] or built-in

MONITOR SPEAKER [32].

These buttons select the channel or channels to be sent to PHONES CONNECTOR [4] or built-in MONITOR SPEAKER [32]. Pressing CHANNEL 1 BUTTON selects channel 1 for monitoring, pressing CHANNEL 2 BUTTON selects channel 2. One or both buttons may be pressed at any time.

This 1/4" tip-ring-sleeve phone jack provides signal output for headphones having input impedance of 8 Ω or greater. Connecting the headphone to this connector cuts off the signal to MONITOR SPEAKER [32].

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May 1991

MX-50II Operation and Maintenance Manual	Section 3 Controls and Indicators
[5] VU METERS	Each VU METER incorporates a PEAK INDICATOR which illuminates when the signal
	reaches a level equivalent to 1040 nWb/m.

[6] INPUT AND OUTPUT LEVEL CONTROLS	These controls adjust the line input and output levels. When SRL SWITCH [7]
	associated with INPUT or OUTPUT LEVEL CONTROLS is pressed, and its indicator
	illuminated, the corresponding level controls have no effect.

[7] SRL SWITCHES AND INDICATORS	When one of these switches is pressed, the “0 VU” indication on VU METER [5]
	corresponds to the reference flux level (SRL: Standard Reference Level).

[8] READY/SAFE SWITCHES AND READY INDICATORS Setting one or both of these switches to “READY” places the corresponding channel(s) into RECORD READY MODE, in which the input(s) to the channel(s) will be recorded on the tape when the transport is placed into RECORD MODE. Setting this switch to “READY” while the MX-50II is in PLAY MODE places the channel in RECORD MODE immediately.

Setting one or both of switches to “SAFE” places the corresponding channel(s) into SAFE MODE, in which recording cannot take place. Setting either READY/SAFE SWITCH to “SAFE” while the MX-50II is in RECORD MODE causes that channel to leave RECORD MODE immediately.

READY INDICATOR flashes when the channel is in RECORD READY MODE, and becomes steadily illuminated when the channel is in RECORD MODE.

[9] INPUT/TAPE SWITCH AND TAPE INDICATOR This switch selects the machine output and monitor signals. When the switch is set to “INPUT”, the signal at that channel's OUTPUT CONNECTOR is the signal present at that channel's INPUT CONNECTOR. When the switch is set to “TAPE”, the signal at that channel's OUTPUT CONNECTOR is the signal present on tape reproduced by that channel's reproduce head. TAPE INDICATOR will be illuminated.

May 1991

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Section 3 Controls and Indicators

MX-50II Operation and Maintenance Manual

								13			10		11
		2							REEL SIZE		SUP	T.UP		TAPE SPEED
		3							S					LO
	6		PEAK						L					HI
10			10 1 2 3
		VU				12	NAB					ZERO	CUE	CLEAR
							IEC
								H	M		S				14
	INPUT
						15	FADER	16						EDIT	17
			1	READY	2	TAPE
				SAFE		INPUT
	OUTPUT
							18	19		20		21		22

Figure 3-2

Transport Control Panel — 2

[10]	REEL SIZE S/L KEY	Selects the tape tension to match the reel size being used.
[11]	TAPE SPEED LO/HI KEY	Pressing this key causes the tape speed to change.
[12]	NAB AND IEC INDICATORS	Indicates the current position of EQUALIZATION IEC/NAB SWITCH [38] on the connector
		panel.

[13]	TAPE TIMER	Displays the current tape location as Hours, Minutes, and Seconds.
[14]	SEARCH ZERO, CUE AND CLEAR KEYS	Pressing SEARCH ZERO KEY places the transport into SEARCH ZERO MODE.
		SEARCH CUE KEY is used to store and/or initiate a search to a stored tape location.

Pressing CLEAR KEY together with another key clears TAPE TIMER [13] or the memory associated with that key.

CLEAR + SEARCH ZERO resets TAPE TIMER to 0.00.00.

CLEAR + SEARCH CUE clears stored cue point memory.

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May 1991

MX-50II Operation and Maintenance Manual		Section 3 Controls and Indicators
[15]	FADER BUTTON AND INDICATOR*	Pressing this button enables the fader start line on FADER CONNECTOR [35] on the
		connector panel. When the fader start function is enabled, PLAY and STOP BUTTONS
		on the transport are disabled. *(MX-50D Only)
[16]	CUE BUTTON AND INDICATOR	Pressing this button during FAST WIND MODES initiates CUE MODE, in which the
		tape lifters retract allowing the tape to be in contact with the reproduce head
		for audio monitoring at wind speed.
		Holding CUE BUTTON pressed causes the tape lifters to remain retracted as
		long as the button is held pressed. Tapping CUE BUTTON quickly causes the
		lifters to remain retracted until the next time CUE BUTTON is pressed.
[17]	EDIT BUTTON AND INDICATOR	Pressing this button while in STOP MODE causes the MX-50II to enter EDIT
		READY MODE, in which the take-up motor is turned off, the safety switch for the
		supply swing arm is deactivated, and EDIT INDICATOR flashes. Pressing PLAY BUTTON
		while in EDIT READY MODE, or pressing EDIT BUTTON while in PLAY MODE, causes the
		MX-50II to enter DUMP EDIT MODE, in which the take-up reel does not rotate
		allowing tape to be “dumped” from the transport.
		NOTE: If there is slack in the tape path and the safety switch for the supply
		swing arm is deactivated, EDIT READY MODE will be activated when EDIT BUTTON is
		pressed, and DUMP EDIT MODE will start when PLAY BUTTON is pressed.
[18] RECORD BUTTON AND INDICATOR		Places the transport into RECORD MODE.
[19]	PLAY BUTTON AND INDICATOR	Places the transport into PLAY MODE. Pressing this button when there is slack
		in the tape path causes the take-up reel to rotate very slowly until the slack is
		removed, then the transport enters PLAY MODE.
[20]	STOP BUTTON	Pressing this button when the transport is in RECORD, PLAY, DUMP EDIT, FAST
		FORWARD, or REWIND MODE causes the tape motion to stop.
[21] REWIND BUTTON		Places the transport into REWIND MODE, in which the tape moves from the
		take-up reel to the supply reel at fast wind speed.
[22]	F.FWD BUTTON	Places the transport into FAST FORWARD MODE, in which the tape moves from
		the supply reel to the take-up reel at fast wind speed.

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Section 3 Controls and Indicators

MX-50II Operation and Maintenance Manual

32
31		31
30		30
23		24
FIX VARI EXT VEM	DOWN	UP
28		29

POWER		1						2
20 10	6	3	10	1	PEAK	20 10	6	3	10	1	PEAK
					2 3						2 3
		VU						VU
MONITOR	INPUT						INPUT

25

	REEL SIZE SUP	T.UP		TAPE SPEED
	S			LO
26	L			HI
	27	ZERO	CUE	CLEAR

S

Figure 3-3

Transport Control Panel — 3

[23] SPEED MODE BUTTON AND INDICATORS	Repeatedly pressing this button causes the speed mode of the MX-50II to
	step through the four speed modes (FIX, VARI, EXT, VEM) in the sequence (if
	the optional VEM PCB ASSEMBLY is not installed, VOICE EDIT MODE cannot be selected).
	In FIX SPEED MODE, the capstan motor speed is controlled by the internal
	crystal oscillator.
	In VARI SPEED MODE, the tape speed is controlled by PITCH CONTROL KNOB [24].
	In EXT SPEED MODE, the tape speed is controlled by the external speed
	reference signal connected to REMOTE CONNECTOR [34] on the rear panel. If the
	speed mode is set to EXT, and the PITCH ENABLE line (Pin 23 on REMOTE
	CONNECTOR) is not activated, FIX INDICATOR will remain illuminated, and EXT INDICATOR
	will flash. Set the speed mode to EXT when using a synchronizer or
	resolver to control the MX-50II. Refer to §2.2 for additional information
	about controlling the tape speed using an external controller.
	In VOICE EDIT MODE (VEM), the tape is reproduced at two times the
	currently selected speed, but the pitch of the signal remains constant.
	If SW1-4 on CONTROL PCB ASSEMBLY is “ON”, the MX-50II cannot enter VARI or
	EXT SPEED MODES when in RECORD MODE.

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May 1991