Ampex MM-1200 User manual

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AMPEX 4890400-02
TABLE OF CONTENTS
TITLE
SECTION 1 DESCRIPTION
General
Tape Transport Assembly
Supply and Takeup
Reel Assemblies
Capstan Drive Assembly
Pinch Roller Assembly
Tension Sensor Assembly
End-of-Tape Arm and Threading Switch Assembly.
Tape Lifter Assembly
Search-to-Cue/Tape Timer Accessory
Transport
Control Assembly
Motor-Drive Amplifier Assembly
Head Assembly
Electronics Assembly
Control Box Assembly
Meter Panel Assembly
Power Supply
Optional
Equipment
Specifications
SECTION 2 INSTALLATION
Equipment Siting
Unpacking . .
..
Power Requirements
Cable Connections .
Initial Adjustments .
Input Signal Setup
Balanced Line .
Unbalanced Line .
Output Signal Setup
Balanced Output
Unbalanced Output.
Sync Transfer Switch .
Speed Selection . . .
Fixed Speed Mode .
Variable Speed Mode
Search-to-Cue and Tape
Timer
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TABLE OF CONTENTS [Continued)
TITLE
SECTION 3 OPERATION
General
Controls
and Indicators
Speed Selection
Fixed Speed Mode
Variable Speed Mode
Line/Monitor
Output Signals
Operating Procedures
Making a Recording - Without Sel Sync
Making a Recording -With
Sel Sync
Reproducing a Previously Recorded Tape
Fast Winding
Fast Winding -Search-to-Cue
Tape
Lifter Defeat
SECTION 4 THEORY OF OPERATION
General
Audio Electronics
Record
Reproduce
Individual Channel Audio Switching
INPUT/REPRO/S/SYNC Switch Circuit.
Sync Transfer Switch
Audio Mute Function.
Record Function .
Master
and Standby Monitor Audio Switching
STANDBY MONITOR Switch Circuit
MASTER MONITOR Switch Circuit
LIFT DEFEAT Switch Circuit
READY/SAFE Switch Circuit
Status Display Circuits
TAPE SPEED Switch Circuit
MASTER MONITOR Switch Circuit
STANDBY MONITOR Switch Circuit
INPUT/REPRO/S/SYNC Switch Circuit.
READY/SAFE Switch Circuit
Bias Amp Module
Record Amplifier
Reproduce Amplifier f
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AMPEX 4890400-02

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AMPEX 4890400-02
TABLE OF CONTENTS (Continued)
,
TITLE
SECTION 4 THEORY OF OPERATION (Continued)
Transport Control . . .
Stop and Braking Logic
Initial Turn On
Brake Release . . .
End-of-Tape
(EaT) .
Record Stop
Dynamic Braking
Tape
Lifter Logic
Lift Defeat Logic
Play Logic ...
Record Logic . .
Fast Forward Logic
Rewind Logic . . .
Tape Tension Control and
Servo.
Tension Error Amplifier
Play/Record Mode
Rewind Mode
Fast Forward . .
Stop
.....
End-of-Tape
Search-to-Cue
and Tape Timer
Tape Timer
..... .
Search-to-Cue . . . . .
Reel Motor Drive Amplifiers
Capstan Servo . . . . . .
Block-Diagram Description
Circuit Description
Power Supply . . .
39-Vdc Regulator
Bias Oscillator
27-Vdc Regulator
15-Vdc Regulator
5-Vdc Regulator .
SECTION 5 MAINTENANCE
General . .
Test Equipment
Cleaning . . .
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TABLE OF CONTENTS (Continued)
TITLE
SECTION 5 MAINTENANCE (Continued)
Demagnetization ..... .
Lubrication. . . . . . . . .
Scrape-Flutter Idler Lubrication
Maintenance Adjustments . . .
Power Supply . . . . . . .
39-Volt Regulator Adjustment
15/27-Volt Regulator Adjustment -
27-Volt Section . . . . . . . .
15/27-Volt Regulator Adjustment -
15-Volt Section . . . . . . . .
Overcurrent Protection Adjustment
5-Volt Regulator Adjustment
Motor Drive Amplifier
Transport Control . . . . .
Preliminary Setup . . . .
Tension Sensor
Arm Calibration
Normalizing
Reel Servos
Tension Adjustments .
Capstan Servo
System. .
Search-to-Cue/Tape Timer
Checkout . .
.. .
Adjustment
... .
Alignment of Photo-Isolators
Mechanical Adjustments. . . .
Takeup
Reel Brake Adjustment
Brake Check and Adjustment
Brake Solenoid
Air Damping
Supply Reel Brake Adjustment
Capstan Servo
Motor . . . .
Tape
Lifter Assembly Adjustments
Tape
Lifter Solenoid Air Damping
Head Assembly
Pinch Roller
Check . . .
Adjustment
End-of-Tape
Arm
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AMPEX 4890400-02

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AMPEX 4890400-02
TABLE OF CONTENTS (Continued)
TITLE
SECTION 5 MAINTENANCE (Continued)
Audio Adjustments .,',.,
7-1/2-ln/S Reproduce Alignment
7-1/2 -15 In/S Record Alignment
15-30 In/S Reproduce Alignment
15-30 In/S Record Alignment,
Distortion Measurement , .
Noise and Erasure Depth .
Bias
Amp Module Alignment
Troubleshooting , , , . , .
Possible Corrective Actions
Causes of Tape Speed Error
Causes of Noise . . . . ,
Causes of Distortion
Causes of Flutter ..,..
Flutter Troubleshooting Hints
Transport
Control , .
Audio Switching
Audio Signal . , , ,
Reproduce
Amplifier
Record Amplifier
Bias Amp Module
Power Supply , , .
Removal and Replacement
Control Box Assembly
Disassembly
Toggle Switch Removal and Replacement
Pushbutton Switch Removal and Replacement
LED Removal and Replacement
Reassembly ,
Reel Motors
Capstan Motor
Head Assembly
Tension Sensor
Pinch Roller Assembly
End-of-Tape Arm and Tape Threading Switch,
Search-to-Cue and Tape Timer Assembly
Tape Lifter Assembly . , , . ,
Power Supply , , , , , , , ,
Motor Drive Amplifier Assembly
Meter Panel Assembly "',
",
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TABLE OF CONTENTS (Continued)
TITLE
SECTION 6 PARTS LISTS AND SCHEMATICS
Indentured List of Assemblies
Numerical List
of Assemblies
Numerical List
of Schematics
APPENDIX A
Integrated Circuits .
APPENDIX B
Transport Control PWA 4050706 Alignment
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AMPEX 4890400-02

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A~PEX 4890400-02
LIST OF ILLUSTRATIONS
Location of Components (Front)
Location of Components (Rear)
Tape
Transport Assembly
Transport Control Assembly . .
Motor-Drive Amplifier Assembly
Head Assembly (Typical)
Electronics Assembly (Typical)
Control Box Assembly
Meter Panel Assembly
Power
Supply . . . .
TITLE
Input/Output Connector Panel
Input/Output Cable Wiring. .
Capstan Servo PWA ....
Search-to-Cue and Tape Timer PWA
Tape Threading Path . . . . . .
Head
Usage for Different Operating Modes
MM-1200 Block Diagram . . . . _ . .
Record Signal Path Partial Schematic . . .
S/Sync and Repro Signal Path Partial Schematic
Audio Control Partial Schematic _ . . . . . .
Divider Voltages with Neutral Control Signal (REPRO)
Divider Voltages with +27V Control Signal (S/SYNC)
Divider Voltages with Ground Control Signal (I NPUT)
Control Panel Simplified Schematic, Channel 1 Shown
Stop and Braking Logic Partial Schematic
Play and Record Logic Partial Schematic
Fast
Forward and Rewind Logic
Tension Servo
Circuits Partial Schematic
Tape
Timer Block Diagram . . . . . .
Search-to-Cue Block Diagram . . . . .
Reel Motor Drive Amplifier Simplified Schematic
Capstan Servo Block Diagram . . . . . . .
Capstan Phase Comparator, Typical Waveform
Power Supply Block Diagram . . . . . .
Power Supply Test Points and Adjustments
MDA PWA Test Point Location . . . . .
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LIST OF ILLUSTRATIONS Continued)
TITLE
Transport Control PWA, Control Locations
Tension Sensor
Arm Calibration
Tape Tension Adjustments . . . . . .
Positioning Tension Sensor
Arm . . . .
Servo PWA Test Points and Adjustments
Waveform at TP2 on Servo
PWA. . . .
Tachometer Preamplifier Adjustment
Tachometer Preamplifier Adjustment Waveforms With Tape
Moving in the Forward Direction
Transport Adjustment Points
Servo Motor Maintenance
Tape
Lifter Adjustment .
Pinch Roller
Adjustment.
End-of-Tape Arm
Tension Arm Dashpot Assembly.
End-of-Tape Arm and Threading Switch Adjustment
30-Hz to 18-kHz Band Limiting Filter
ASA 'A' Weighted Filter
Control Box Case Removal
Control Box Assembly
Switch PWA Disassembly
Switch Replacement
Transport Disassembly (Top)
Transport Disassembly
(Bottom)
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AMPEX 4890400-02

TABLE
1-1
1-2
2-1
2-2
2-3
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3-2
3-3
3-4
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4-2
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Optional Equipment
Specifications . . .
Power Supply Strapping
Speed Strapping . . .
LIST OF TABLES
TITLE
Tape Speeds for Various Input Frequencies
Control Box Assembly -Controls and Indicators
Search-to-Cue and Tape Timer Controls and Indicators
Electronics Assemblies -Operator Controls
for a Typical Channel
Line Output/Monitor Signals
Audio Switching Bus Levels
High-Frequency Equalization Components.
Test Equipment and Maintenance Materials
Transport Brake Torques .. . . . . .
Electronics Assembly - Alignment Adjustments
Ampex Alignment Test Tapes .....
Rotational Rates (Revolutions/Second) . . . .
Troubleshooting Hints -Transport System
Troubleshooting Hints -
Audio Switching System
Troubleshooting Hints -Power Supply . . . .
AMPEX 4890400-02
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ix/x

13550-1
MM-1200 Multichannel Recorder/Reproducer
1-0
AMPEX 4890400-02