Scully 280B Series Instructions for use

-ADDENDUM
p
MODEL: __ M_ o_d_e_I_2_8_0_B_ S_e_r_ ie _s_ R_e_c_o_r_d_e_r _/ _R ..:!,. e__r_o_d_u_c_ er ______ Date : May 18, 1978
PUBLICATION AFFECTED : Instruction and Maintenance Manual 02
ADDENDUM NO. --
REASON FOR ADDENDUM __ Pr _ ovide instructions for decoding CODE block on system
labels (name plate),
The following information is provided on how to "decode" the CODE block on system label
for Model 280B Series Recorder/Reproducer . The purpose of these instructions is to en-
sure that the user supplies the factory with the correct information, on his particular re-
corder/reproducer, from the name plate affixed to the recorder. This is of utmost impor
ance when ordering spare parts or concerns service information. Figure 1 depicts a typic
name plate for a Model 280B and what the CODE numbers represents.
®Scully 280 B I
Professional Recorder/Reproducer
I~~~~~~~~
~
r 01
02
~~~ ~ ______ ~~~ __ ~~---~~XX 03
DICTAPHONE CORP . MTN . VIEW. CA MADE IN U.S . A.
04
05
06
NAB 3.
75 - 7.5 IPS
NAB 7. 5 - 15 IPS
IE C 7. 5 - 15 IPS
NAB 15 -AES 30 IPS
IEC 15 -AES 30 IPS
DIN/IEC 3.75 - 7.5 IPS
-FT
Mono Full Track (.25")
01
Mono Half Trac}; : (.25")
02
Stereo Two-Track (.25")
03
Quad Four-Track (.50")
24
Stereo Four-Track (.25")
44
Quad Four-Track (.25")
NOTE:
This addendum should become a permanent part of the manual until such time as the man a
is revised (reprinted). This addendum should be placed at the front of the manual.
1 1
Sheet __ of __
........ _®Dictaphone
Audiol Electronics Division

.-------I ~ Scull,#-------------------.
Recording Instruments
Model 2808 Series
Recorder IReproducers
Instruction and Maintenance Manual
AUDIO/ELECTRONICS DIVISION OF DICTAPHONE CORPORATION
475
Ellis Street, Mountain View, California 94043 U.S.A.
[phone]
TLX 345524
Serial No.:_ ___ _
Catalog No.
200612 · 03
Julv 1977
Date Rece ived: ____ _
Printed in U.S.A .

WARRANTY
SCULLY RECORDING INSTRUMENTS
DICTAPHONE VOICE FREQUENCY COMMUNICATIONS INSTRUMENTS
Dictaphone Corporation
WARRANTY CONDITIONS: THERE ARE NO WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING ANY
WARRANTY OF MERCHANTABILITY, BEYOND THOSE STATED HEREIN
OR WHICH EXTEND BEYOND THE
DESCRIPTION OF THE EQUIPMENT.
Dictaphone warrants the products of its manufacture to be free from defects in workmanship and material
under normal and proper useand service for the appropriate periods specified below. Dictaphone assumes no
obligation to repair or replace equipment which has been altered or repaired by other than Dictaphone ap-
proved
procedure; been subject to misuse, misapplication, improper maintenance, negligence or accident;
had its serial number or any part thereof altered, defaced, or removed; or been used with parts other than those
approved by
Dictaphone (except standard tapes, transistors, diodes, fuses or lamps).
DICTAPHONE'S OBLIGATIONS ARE LIMITED TO REPAIR
OR REPLACEMENT OF BROKEN OR DEFECTIVE
PARTS OR,
AT THE OPTION OF DICTAPHONE, TO REFUND OF THE PURCHASE PRICE. THE FOREGOING
ARE PURCHASER'S EXCLUSIVE REMEDIES. DICTAPHONE ASSUMES NO LIABILITY FOR SPECIAL OR CON-
SEQUENTIAL DAMAGES.
All
Dictaphone and Scully instruments are warranted to be free from defects in materials and workmanship for
one year to the original using purchaser except for motors and heads such as tape Reproduce, Record and
Erase Heads,
which are warranted for 90 days. Dictaphone will replace all parts free of charge for 90 days.
Thereafter,
Dictaphone will replace all parts, except for motors and heads, free of charge, except for labor,
during the balance of the warranty period.
The original using buyer must properly fill out and send the warranty card to the factory within ten days from
delivery to establish beginning of warranty period . Failure to do so will require evidence of the bill of sale to
establish warranty claim.
In all warranty transactions involving equipment sold through a Dictaphone or Scully franchised dealer, dis-
tributor, or exporter, it is the responsibility of the dealer , distributor, or exporter to repair or replace the defec-
tive parts.
Dictaphone will provide said agent with replacement parts covered under the warranty .
When necessary
to return parts or equipment for replacement or repair, please write, wire or phone the Division
Service
Department in Mountain View for return authorization , supplying the following:
a. Identify the part in question using the part number and description in the parts manual list.
b. Identify the type, model number and serial number of the unit in which it is used, giving the date of purchase
and name of distributor or supplier.
c. Describe the nature of the defect and reason for replacement or service.
PLEASE
DO NOT return any part of equipment until specifically requested to do so. Unless otherwise agreed,
transportation charges to return parts or equipment must be prepaid.
AUDIO/ELECTRONICS DIVISION OF DICTAPHONE CORPORATION
475 ELLIS STREET, MOUNTAIN VIEW, CALIFORNIA 94043 • TELEPHONE [phone]

Model 280B
CONTENTS
Page
SECTION 1. GENERAL INFORMATION ....... . . . .. ... . ......... ... 1-1
1.1
GENERAL ................ .. .... . ................... , 1-1
1.2 TAPE
TR A NSPORT ................................... 1-4
1.3 ELEC
TRO NIC ASSEMBLY. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-4
1.4 HEAD ASSEMBLY . .. . . . ... .. ........................ 1-4
1.5 OPTIONAL AND ACCESSORY EQUIPMENT. . . .. .. ... . .... 1-4
SECT ION 2. INSTALLATION . .. ... ... .. . ............. .. .......... 2-1
2.1 GEN
ERA L ... . . ... . . .. . ............................ . 2-1
2.2 UNPACKING ..... .. ................................ 2-1
2.3 CONSOLE MOUNTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.4 R AC K M OUNTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-1
2.5 CABLI G
INTERCO NN ECTIONS. . . . . . . . . . . . . . . . . . . . . .. 2-3
SECTION 3. OPERATION ...................... . ... ..... . ....... . 3-1
3.1
GENERAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-1
3.2 TAPE T
HREADI NG. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-1
3.3 S
ELE CTI G SPEED AND APPLYING POWER. . . . . . . . . . . .. 3-1
3,4 PLAYBACK MODE .. . .... ... .. . .... . ... . .... . ...... .. 3-1
3.5 STOPPING
THE UNIT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-1
3.6 RECORD MODE ........... . .... .. .... .. .... . . . .... " 3-1
3.7 SYNC
MODE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-3
3.8 EDIT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-3
SECTION 4. PREVE NTIVE IVIAINTENANCE .. . ...................... 4-1
4.1 GENE
RAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-1
4.2 CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-1
4.3 LUBRI A TI ON ............ . ............. . ........... 4-1
4.4
DEMAGNETIZING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-1
SECTION 5. FUNCT IONAL CHECKS AND ADJUSTMENTS. . . . . . . . . . . .. 5-1
5.1
GENERAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-1
5.2 Functional Che ck ......... . . . .... .. .. . ............... , 5-1
SECTION 6. THEORY OF OPERATION . .... ... . .... .. .... ... ....... 6-1
6.1
ELECTRONICS ASSEMBLY .......................... " 6-1
6.2 RECORD MODE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-1
iii

iv
Model 280B
CONTENTS (Continued)
Page
SECTION 6. THEORY OF OPERATION (Continued) . ........... . ....... 6-1
6.3 PLAY MODE ........................................ , 6-1
6.4 SYNC MODE ........................................ , 6-1
6.5 SQUELCH CIRCUIT
.......................... . ...... " 6-1
6.6 TAPE TRANSPORT ASSEMBLY. " ... ... ............... , 6-1
6.7 CONSTANT
TENSION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-1
6.8 TRANSPORT LOGIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-1
SECTION 7. MAINTENANCE......................... . ............ 7-1
7.1 MECHANICAL ADJUSTMENT
.......................... . 7-1
7.2 BRAKE ADJUSTMENT
......................... . ... . .. . 7-1
7.3 Tape Head Assembly Adjustments ....................... . . 7-1
7.4
Motion Sense
Adjustment ....... .. ............ . ........ . 7-3
7.5
Tension Posts
.......... . ..... .. ..... . .... . ........... . 7-3
7.6
Pinch Roller Adjustment ........... . .... . .............. . 7-6
7.7
Constant Tension Adjustment ........................... . 7-8
7.8 ATL
Adjustments .......... ... ....................... .
7-9
7.9 CHECKOUT AND ALIGNMENT
PROCEDURES ........ . . . . .
7-9
7.10
Test Equipment Required ..... ... .... .. ............... . . 7-10
7.11
Preliminary
Procedures ................................ . 7-10
7.12 Playback Alignment ........... . ........ . ........ . ..... . 7-10
7.13
Record Alignment
............. . ...................... . 7-12
7.14
Record Bias
Set .......................... . ........... . 7-12
7.15
Record Calibrate Alignment
............................. . 7-16
7.16
Record Equalization
................................... . 7-16
7.17
Erase
Alignment ............ . ............. . ........... . 7-16
7.18
Depth of Erase ....................................... . 7-16
7.19 Signal-to-Noise
Ratio ......................... . ........ . 7-16
7.20
Distortion .... . ................................... .. . 7-16
7.21
Flutter ............................................. . 7-17
SECTION 8. SCHEMATIC DIAGRAMS AND PARTS LIST .............. 8-1
8.1 GENERAL ........ " ....... . ........ . ... .. ....... .. 8-1

Model 280B
ILLUSTRATIONS
Page
1-1 Professional
Recorder/Reproducer Series 280B . . . . . . . .. 1-1
1-2
Remote Control Unit Accessory. . . . . . . . . . . . . . . . . . . .. 1-5
2-1
Mounting Dimensions .. ... ....................... 2-2
2-2
Interconnection Diagram. . . . . . . . . . . . . . . . . . . . . . . . .. 2-4
2-3
Power Supply Jumper . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-5
3-1
Controls and Indicators. . . . . . . . . . . . . . . . . . . . . . . . . .. 3-2
3-2
Tape Threading Path . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-3
6-1
System Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-2
6-2
Transport, Bottom View. . . . . . . . . . . . . . . . . . . . . . . . . .. 6-3
7-1
Brake Adjustments ..... . ......................... 7-2
7
-2 Suggested Method of Adjusting Brake Torque. . . . . . . . .. 7-3
7
-3 Head Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-4
7-4
Motion Sense Adjustment . ..... .. . . ............... 7-5
7-5
Tension Post Adjustments .. ....................... 7-6
7-6
Pinch Roller Adjustment. . . . . . . . . . . . . . . . . . . . . . . . .. 7-6
7-7
Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-7
7
-8 Constant Tension Adjustment Procedures. . . . . . . . . . . .. 7-8
7
-9 Constant Tension Assembly ....................... , 7-9
7-10 ATL Adjustment ..... .. ......................... 7-9
7-11
Initial Test Setup ......... . ...................... 7-10
7-12 Electronics Assembly, Top View. . . . . . . . . . . . . . . . . . .. 7-11
7-13
Equalization PWA Adjustments. . . . . . . . . . . . . . . . . . . .. 7-12
7-14 Record/Playback Amplifier PWA Adjustment
and Test Points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-13
7-15
Regulator, Bias Oscillator and Amplifier PWA .......... 7-14
7-16 Bias Amplifier PWA Adjustment and Test Points .. . ... " 7- 15
8-1 Transport Logic, Schematic Diagram· . . . . . . . . . . . . . . .. 8-3
8-2
Regulator, Bias Oscillator and Amplifier PW A ......... 8-5
8-3 Bias
Amplifier PW A, Schematic Diagram. . . . . . . . . . . . .. 8-7
8-4
Record/Playback Amplifier PWA, Schematic Diagram. . .. 8-9
8-5
Record/Playback Equalization PWA ................. 8-11
8-6
Motherboard PWA Schematic Diagram ............... 8-13
8-7 Primary Power Supply, Schematic Diagram ........... 8-15
8-8 Relay Control Chassis Interconnect ................. 8-17
8-9 Erase Head Matching Board Schematic Diagram ........ 8-19
8-10
Motion Direction Sensor PWA ..................... 8-21
8-11
Squelch PWA ............ . ..................... 8-21
8-12 Remote Control .................. . . ... ......... 8-22
8-13 Line Amplifier PWA Monitor and Speaker Assembly .... 8-23
8-15 Transport Assembly (1 of 2) . . . . . . . . . . . . . . . . . . . . . .. 8-31
v

vi
Model 280B
ILLUSTRATIONS (Continued)
8-15
Transport Assembly (2 of 2) ..................... .
8-32
8-16
Transport Subassembly (sheet 1 of 2) .............. .
8-35
8-16
Transport Subassembly, (sheet 2 of 2) .............. .
8-37
8-17
Interconnecting Cable Assembly .................. .
8-39
8-18
Tape Break Switch Assembly ................. .. .. . 8-41
8-19
Transport Control Chassis Assembly ..... . ......... .
8-43
8-20
Capstan
Motor Kit ............................. .
8-45
8-21 Pinch Roller Assembly ................ . ......... . 8-47
8-22
Dancer Assembly ........................ ..... . .
8-49
8-23 Tape Break Arm Assembly ...................... . . 8-51
8-24 Head Bridge Assembly
..................... .... . . 8-55
8-25
Pinch
Roller Connecting Rod Assembly ........... . . .
8-57
8-26
ATL
Solenoid Assembly ................... . . ... . 8-59
8-27
Primary Power Supply ..................... ... .. . 8-63
8-28
Torque Motor & Brake Assembly, Supply .......... . 8-65
8-29
Torque Motor and Brake Assembly, Take-Up ........ . 8-67
8-30
ATL Linkage Assembly
......................... . 8-69
8-31 Turntable Reel Assembly Parts Location ............ . 8-70
8-32
Transport Control Logic PW A . . . . . . . . . . . . . . ...... . 8-75
8-33
Switch Plate Assembly
.......................... . 8-77
8-34
Transport Control Logic Harness Assembly .......... . 8-79
8-35
Transport Control Power Harness Assembly ......... . 8-81
8-36
Capstan
Motor Assembly ........................ . 8- 83
8-37 Scrape Filter Assembly ...................... . .. .
8-85
8-38
Record Head Assembly ....................... . . . 8-87
8-39 Playback Head Assembly
........................ .
8-89
8-40 Head Cable Assembly .
... ....................... . 8-91
8-41 Erase
Head Assembly ........................... . 8-93
8-42
PWB and Erase Head Cable Assembly, Full-Track ..... . 8-95
8-43
PWB and Erase Head Cable Assembly, 4-Track ....... . 8-97
8-44
Power Supply PW A ............................ . 8-99
8-45
Torque Motor Assembly ........................ . 8-101
8-46
Torque Motor Brake Plate Assembly ............... .
8-103
8-47
Motion Direction Sensor PW A .................... . 8-104
8-48
Solenoid Brake Plate Assembly .................... .
8-105
8-49 Brake
Plate Assembly. ' .......................... .
8-106
8-50
Electronics Assembly, Primary .................... .
8-107
8-52
Electronics Chassis Subassembly .................. . 8-111
8-53
Bias Amplifier,
Schematic Diagram ................ .
8-115
8-54
Motherboard PW A ............................. .
8-119
8-55
Regulator, Bias Oscillator and Amplifier PWA ........ .
8-125
8-56
Record/Playback Control Panel Assembly ........... .
8-129
8-57
Record/Playback Equalization PW A ................ .
8-133
8-58
Record/Playback PWB Subassembly ............... . 8-135
8-59
Control Panel Harness .......................... .
8-137
8-60 Squelch
PW A ... ' .............................. .
8-139

Model 280B
ILLUSTRATIONS (Continued)
TABLES
8-61 Record/Playback Amplifier PWA .................. .
8-62 Console Assembly
............................. .
8-66
Remote Control Assembly .. ..... .. ............. . .
8-68
Monitor Speaker Panel Assembly .................. .
8-69 LAA
500 Line Amp PW A .... . ......... . ........ .
8-70 Tension Sensor PW A ..................... ... .. . .
8-71 Light
Sensor Assembly .......................... .
1-1 Models
of 280B Series Recorder/Reproducer .. .. ..... .
1-2
Specifications ................................. .
2-1
Pow er Supply Jumper .......................... .
6-1
Transport Logic Operation ....................... .
8-1
Schematic Diagrams and Parts List . .. .... . ........ . .
8-2 Abbreviations
... . ............................. .
8-3
Manufacturers Code Numbers and Addresses ......... .
8-143
8-145
8-153
8-155
8-157
8-159
8-160
1-2
1-2
2-3
6-5
8-24
8-161
8-163
vii

Model 280B
General Information
SECTION 1
GENERAL INFORMATION
1.1 GENERAL
The Scully 280B Recorder/Reproducer, Figure 1-1,
is a professional magnetic tape recorder designed
primarily for use in recording studios, broadcast-
ing stations, and other applications that require
exacting performance specifications and reliability
standards. The complete Wlit consists of a tape
transport mechanism and electronics assembly.
The equipment can be mounted in a console or
a standard 19-inch (48.26 cm) equipment rack.
The configurations of the 280B Series are listed
in Table 1-1. Complete specifications for the 280B
Series are contained in Table 1-2.
Figure
1·1. Professional Recorder/Reproducer Series 280B
1·1

1-2
General
Information
Model 280B
Table 1-1. MODELS OF 280B SERIES RECORDER/REPRODUCER
MODEL
NUMBER
DESCRIPTION
TAPE WIDTH
(INCH)
280B-FT One-Channel, Full-Track (Mono) 0.25
280B-l
One-Channel, Two-Track (Half-Track Mono)
0.25
280B-2 Two-Channel, Two-Track (Stereo)
0.25
280B-4 Four-Channel, Four-Track (Quad)
0.50
280B-24 Two-Channel, Four-Track (Quarter-Track
Stereo)
0.25
280B-44
Four-Channel, Four-Track (Quad)
0.25
Table 1-2. SPECIFICATIONS
Frequency Response Using 3M 206 tape, or equivalent:
in/s
cm/s Frequency Response
30.00 76.2
±2 dB at 50 Hz to 20 kHz
15.00 38.10
±2 dB at 30 Hz to 18 kHz
7.50 19.05 ±2 dB at 30 Hz to 15 kHz
3.75 9.52
±2 dB at 30 Hz to 10 kHz
Signal-to-Noise
Ratio
Using 3M 206 tape, or equivalent, at peak record
level of 500 nWb/m, with weighted noise and
equalization:
Full Half Two
Four Four
in/s
Track
Track
Track Track Track
0.25"
0.25" 0.25"
0.50"
0.25/1
30.00
72 dB 68 dB
68 dB 68 dB 65 dB
15.00
72 dB 68 dB
68 dB 68 dB 65 dB
7.50 72 dB
68 dB 68 dB 68 dB
65 dB
3.75
68 dB 64 dB
64 dB 64 dB 61 dB
Flutter and Wow Weighted
peak flutter (ANSI S4.3, 1972; lEC 386, 1972)
in/s
DC Servo
AC Motor
30.00 0.04%
15.00 0.04%
0.08%
7.50 0.05%
0.10%
3.75 0.10% 0.20%

Model 280B
General
Information
Table 1-2. SPECIFICATIONS (Continued)
Distortion
Head and Track
Configuration
Speed Accuracy
Standard Operating
Level (Playback Fluxivity)
Start and Stop Time
Wind Time
Reel Sizes
Inputs
Outputs
Power Requirements
Tape Widths
Tape Speeds (Two)
Motors
Brakes
Alignment ControIs
500-Hz
third harmonic using 3M206 Tape or equivalent;
at peak record level (500 nWb/m), less than 3%; at stan-
dard operating level, less than 0.6%.
See Table 1-1.
±0.1%
with DC Servo; ±0.2% with AC motor throughout
reel at all speeds, using 1.5 mil tape.
3.75 and 7.50 in/s: 200 nWb/m at 1000 Hz
7.5,
15 and 30 in/s: 250 nWb/m at 1000 Hz
0.25-in
tape: at 15 in/s reaches nominal speed, ±0.1%, in
200 ms with a full supply reel. From Play tape moves less
than 1.5 inches (3.81 cm) after pressing STOP. At wind
speed, tape stops in less than 5 seconds.
Less
than 60 seconds for 2400-foot (730.5-meter) NAB
type A reel, 0.25-inch tape
To l1.5-inches (28.2 cm) (CCIR)
Floating Bridging: 10 Kilohms impedance; minimum
level, 200 mV
+24 dBm into 600 ohm Load (output impedance 60 ohms)
105 to 125 or 220 to 240 Volts, 50/60 Hz.
Power Consumption at 117 Vac: 60 Hz
223 VA for 1 & 2 Channel
328 VA for 4 Channel
0.25 and 0.50-inch
3.75 in/s and 7.5 in/s, or 7.50 in/s, 15 in/s and 30 in/s with
optional servo. Equalization switches automatically with speed.
Capstan: Direct drive hysteresis synchronous (Phase-lock
servo
optional).
Reel: Induction torque motor (2)
Dynamic plus disc
Equalization controls (2 Record, 4 Play), Bias Adjust, Record
Cal., Sync Level, Play Cal., Bias Level Set
1-3

General Information
Model 280B
Table 1-2. SPECIFICATIONS (Continued)
Bias and Erase
Frequency
160 kHz
Erase Efficiency
Greater than 75 dB at 1 kHz below 500 nWb/m
Remote Control Duplicates transport controls, except that ATL
defeat is provided by holding down either of the
fast function buttons.
NOTE: Specifications subject to change without notice or obligation.
1.2 TAPE TRANSPORT
The tape transport handles 0.25-inch (6.35 mm) or
0.50-inch (12.70 mm) magnetic tape on reels up to
11.5 inches (28.2 cm). Tape control functions in-
clude
tape take-up TENSION (reel-size) switch;
Fast Forward and Fast Reverse, STOP, START,
and Edit pushbuttons; and a CAPSTAN High/Low
speed select switch. An automatic tape lifter (ATL)
is provided to minimize tape and head wear during
Fast Forward (FF) and Rewind (FR) modes. For
fast cueing, a manual defeat of the ATL functions
is also provided. The pushbuttons are lighted to in-
dicate visually
actual transport mode of operation.
1.3 ELECTRONIC ASSEMBLY
The electronic assembly contains: the record/play-
back control panel and amplifier assemblies; a regula-
tor, bias oscillator,and
amplifier prin ted wiringassem-
bly
(PWA); and a permanently mounted electronics
motherboard assembly. An equalization PWA plugs
into each record/playback amplifier PWA Equaliza-
tion is switched automatically when tape .speed is
selected. A
RECORD READY switch on the record/
playback control panel allows recording on any or all
channels. Each
record/playback control panel con-
tains a vu
meter that indicates playback or record
levels. One record/playback control assembly is provi-
ded for each channel. One regulator, bias oscillator,
and amplifier PWA provides dc voltages and biassig-
nals
for one or two channels. An additional bias
Amplifier
PWA is used for four-channel systems.
1-4
1.4 HEAD ASSEMBLY
The head assembly contains three head stacks:
erase,
record, and playback. Refer to Table 1-1.
1.5 OPTIONAL AND ACCESSORY EQUIPMENT
The following optional and accessory equipment
is available for use with the 280B Series Recorders.
•
Remote Control Unit, Figure 1-2: The table
model has a 31-foot long cable with connec-
tor P1l1 installed. The panel mount configu-
ation includes mating connectors and pin ter-
minals for a cable of the desired length up to
50 feet.
• Capstan servo system option: Provides in-
creased speed
accuracy, less flutter and wow,
and improved frequency response. The servo
system is designed around a printed circuit
motor. A crystal oscillator provides the basic
tape speed reference frequency with an opti-
cal tachometer serving as the functional
reference.
• Varisync Model VS-76: Varies tape speed
from any of the preset speeds (3.75, 7.5, 15
or 30 in/s) by +50% to -25% and can lock
the capstan motor speed to a pre-recorded
control track. The Varisync accessory can

Model 280B
General Information
be fitted to all 280 B family of recorders
• Record/reproduce Equalizers, plug-in type,
equipped with a capstan servo option having
one required per channel:
the proper transport control logic printed
wiring assembly. NAB
3.75 or 7.5 in/s
• Monitor
speaker
Speaker
accessory
Accessory: The monitor
is available for single-
NAB
7.5 or 15 in/s
IEC 7.5 or 15 in/s
channel systems. It mounts in the electronics
DIN/lEC 3.75 or 7.5 in/s
assembly and has its own volume control.
NAB AES 16 or 30 in/ (servo-equipped
• Console
Cabinets:
models)
lEC AES 15 or 30 in/s (servo-equipped
One- and two-channel
models)
Four-channel
Special equalizations available.
Figure 1-2.
Remote Control Unit Accessory
1-5/1-6

Model 280B
Installation
SECTION 2
INSTALLATION
2.1 GENERAL
Scully 280B Series equipment is shipped in specially
desig ned packaging and is fully prote ct ed from nor-
mal shipping shock and vibration. After unpacking,
examine the equipment for possible damage before
connecting ac power. Notify the carrier immediate-
ly if any damage is noted. Before throwing away
the packing material, make sure that all invoiced
items are present .
The tape transport and electronics assembly are
regularly shipped in two cartons. The power cord
(plug-in), mounting hardware, flywheel, and Allen
wrenches are located in a hardware bag that is
packed with the transport mechanism. A 10.5-
inch take-up reel is also in the shipping carton.
The 280B is designed to fit in a standard 19-inch
equipment rack, cabinet, or console. Figure 2-1
shows the mounting dimensions of the 280B.
2.2 UNPACKING
A
Lift the transport mechanism out of the car-
ton using the two shipping straps provided for
this purpose.
Do not lift by the motors or their shafts.
B. Remove the straps.
c. Remove the electronics assembly from the
carton.
D. Position the large carton so that the arrow
is point up.
F.. Remove and assemble the console riser and
el e ctron ics shelf.
F. Fa sten this assembly to the top of the console
with the bolts provided.
2.3 CONSOLE MOUNTING
A Mount the transport into the cutout on the
top surface. Tighten the mounting screws.
Remove the capstan flywheel from the hard-
ware bag and mount it on the capstan motor
shaft.
B. Mount the electronics assembly in the elec-
tronics cabinet above the transport. In sys-
tems which have two electronics assemblies,
mount the channels 1 and 2 assembly in the
top rack position.
c. If the electronics drawer has been disconnec-
ted from the rail slides, carefully reinstall the
drawer as follows:
1. Pull the left- and right-hand slides out of
the housing as far as they will go.
2. Position the electronics drawer so that
the drawer rails rest on top of the slides.
3. Gently push the drawer all the way in
until the drawer rail catches drop into
cutouts in the slides.
4. Pull the electronics drawer out to the
service position and check that both
drawer rail catches drop into place.
2-4 RACK MOUNTI NG
A Mount the transport in the equipment rack
U$ing the panel mounting hardware supplied.
The recommended rack placement is for the
electronics assembly to be mounted directly
below the tape transport, or within the limit
of the connecting cables. Remove the fly-
wheel from the hardware bag and mount it
on the capstan motor shaft.
2-1

2-2
Model 280B
Installation
f
2-7/8 MIN . FOR
REEL CLEARANCE
r------ ----- --- ------------,
\_I--r-
(0
o
I
I
:t:
4-3/4
--+15 ~ 3/4
~=d21
J: _
1 1/ 32_-l--.<~ TRANSPORT
2 INCH ~~~~AL ~\L
I _ _ __
J • 19 ASSEMBLY
\"' 1-3/4 MIN . FOR 10.5 IN.OIA. REEL CLEARANCE
CLEARANCE~
~LECTRlNICS ASSY
l ~ l : I[: ~1:;;r"4 1 ll ~~I ~ 1 _ CI==nnI 1L...lL..---1
\ ,... ______ 19 __ _ __ "jj-11I32 10 - - --.l L
CONVERSION TABLE FOR 280B MOUNTING DIMENSIONS
Figure 2-1. Mounting Dimensions
INCHES
11/32
1-1/2
1-3/4
2
2-
1/4
2-7/8
4
METRIC
METRIC
EQUIVALENT
INCHES
EQUIVALENT
8.73 mm 4·3/4 12.07
em
3.811.m 5-1/4 13.34
em
4.45
em 8-1/2 21.59
em
5.08 em 10 25.40
em
5.72 em 15-3/4 38.10 em
7.30 em 19 48.26
em
10.16 em

Model 280B
B. Mount the electronics assembly in the rack
below the tape transport using the mounting
hardware supplied. In units which have two
electronics assemblies, mount them below the
transport with the channels 1 and 2 assembly
above
the channels 3 and 4 assembly. In a four-
amplifier system, the regulator, bias oscillator,
and amplifier PWA is mounted in the channels
1 and 2 assembly. The bias amplifier PW A is
mounted in the channels 3 and 4 assembly.
NOTE
The tape transport will not operate unless
it is connected to the electronics assembly.
2.5 CABLING INTERCOI\INECTIOI\JS
Interconnect the tape transport and the electronics
assemblies as shown in Figure 2-2, and detailed
below:
A
Connect cable W1 from the head bridge sockets
J112, J113, and J114 to head input socket
J125 on the rear of the electronics assembly.
Connect the cable conne c tor marked P125A
to J125A on the upper electronics assembly,
and the connector marked P125B to J125B
on the second electronics assembly, etc.
B. Connect cable W2 between electronics power
connector J109 on the transport control as-
sembly and
the power input connector J126
on the upper electronics assembly.
C.
If two or more electronics assemblies are
used, connect cable W3 between the J123
power transfer connector on all electronics
assemblies.
D. If the remote control assembly is used, con-
nect its cable to remote socket J111 on the
transport control chassis assembly.
Installation
E. Connect cable W4 between ac power plug
J201 on the power supply and a 115-120 volt,
50(60 Hz power source. If the recorder is
operated at a different line voltage, the
jumper plug on the power transformer input
winding, Figure 2-3 and Table 2-1, should be
changed for optimum performance. Assure
proper system grounding and completely
check all cables before applying power.
F. A female XLR type audio connector is required
to connect the output of each amplifier.These
connectors are plugged into LINE OUT recep-
tacles
J120 and J118 provided on the rear of
the electronics assembly.
G. A male XLR type audio connector is required
to connect the input to the amplifier. These
connectors are plugged into LINE IN recep-
tacles
J119 and J117 located on the rear of
the electronics assembly.
Check that the switch (Figure7-7),located
on the power supply, is in the correct
position for the tape width being used.
H. Check that dummy plug P110 is installed in
inverter socket J110 on the transport
assembly.
Table 2-1. Power Supply Jumper
VOLTAGE (Vac)
240
220
125
105
115
CONNECTION
PI to E8
PI to E10
PI to E12
PI to E14
PI to E23
2-3

----- -
2-4
Model 280B
Installation
CONNECTOR OESlWDOH lLGc:NP
JIOt TAPE BREAK
JKl2
",106 TORQUE
,J07 CAPSTAN
JI08 MOTION
TRJIt I III 2
JItO
Jill
JII2
J113
JII4 PLAY ~AD
JII'
Jnl
JII7 LINE
..rillS LINE OUT,
JII9 UHf IN,
JI20 UHf OUT,
JIZ3 POWER
TRK :5 a 4
..H2'
I€AD
J 126 POWER
.1201 A- C.
[!]
\
. ~
wS
..... IH POWER SUPPLY
Jim TORQUE MOTOR - TAK[-LP
JK)4 sa..EHOKl, PfiCH ROli...ER
Jm SOLDtOIQ, AUTO . TAPE LIFTER
~ , Sl.PPLY
MOT OR
DIRECTION SENSOR
Jt09 ELECTRONICS POWER
INVERTER SOCKET. S ER vO ELECTRON ICS
REMOTE SOCKET
ERASE HEAD MIDGE SOCJltET
RECORD HEAD SRIDG[ SOCKET
elUDGE SOCXfT
HEAD PHONES . CHAHNE1..S I AN):5
HEAD ptt()HES. O(A~LS 2 AND 4
~, CHANNEL I
CHANNEL I
CHAHNEl 2:
.- . -- .. - -- ~
® I
POWER
.3
HEAD INPUT
INPUT
JIX
____ JI _" A_ ___ -----.J
ELECTRONICS uNIT 0 0 o o
CH~~~4 . ~ --L. ~r:.ER Jl23 lINE.QUl LI NE IN
2017 40 JI20 014 Jllg
au,.El 2
TftAMSf'ER
'NtUT SOQI;£T
INPUT
PCMER
__ _. ---1
HEAD INPUT
JI25 B I
---- -- ---- - --- J- IIO -I p~o
~ . [J
-_ . ~ I
I
-- -- - - --- - -
~ l
/----
.4
liT VAC SO / SOH.
CMLL - P\..U& IDEHTIf'ICATtoN
NOTES:
r!) PUO. ou_v Pl.UG MUST BE INSTALLED AND WITH
JUMPEft IN PLACE
AS SHOWN (200159) WHEN
SERVO IS NOT USED .
CABLES WI-2 AND W3 USED FOR QUAD SYSTEMS ONLY .
SE R VO MO TOR AND ELECTRO NICS SHOWN IS OPTIO NA L.
CAPSTAN MOT OR IS : O"'N( C T( O TO JI 07 WHEN SER VO
MOT OR IS NOT USE O.
CABLE NO
SCUlLY PAlt"'R«) TRANSPOftT END
Ell"""""",, £HI)
[!1·~-2
W2
0
W3
W4
DW5
w6
•
200~6a - 02
200'S8 -03
200673 -01
20084:5-01
160126
20 1 445 -xx
20 1 346-xx
PilI . P1l3. Pll4
.
• 101 -
P201 (TO EX'tA.CJ
--
JI IO
Pt2~CTRK 'S2)
PIZ'(TRK3a.)
.12 •
P12' - PII'
--
- -
Figure 2-2_ Interconnection Diagram

Model 280B
Installation
~~~~=~ ~JUMPER WIRE
SEE DETAIL A
DETAIL A
Figure 2-3. Power Supply Jumper
2-5/2-6

Model 280B
Operation
SECTION 3
OPERATION
3.1 GENERAL
Operating controls for the 280B Series tape trans-
ports are located on the front panel assembly of the
tape transport mechanism. Operating controls for
the amplifiers are located on the record playback
control panel. The transport pushbuttons contain
lamps . to indicate the mode of operation of the
transport.
The control and indicators are illustrated in Figure
3-1.
3.2 TAPE THREADING
Before installing and threading the tape, make sure
that routine procedures for tape path maintenance
have been followed according to the recommended
practice outlined in section 4. Figure 3-2 shows the
tape threading path. Set the TENSION control to
HI for large reels and LO for small reels.
3.3 SELECTING SPEED AND
APPLYING POWER
A. Tum the POWER switch to on. The STOP
pushbutton and the vu meter lamps light to
indicate that power is on.
B. Select
the desired capstan speed (CAPSTAN
HIGH/LOW switch).
The CAPSTAN switch
automatically changes electronic equalization.
~1
Do not change tape speed while
in
the Play mode. Damage to the
machine may result.
3.4 PLAYBACK MODE
A. Thread the recorded tape on the transport.
B. Set the Monitor switch to PLAYBACK.
C.
Set the Function switch to SAFE.
D. Press the START pushbutton.
3.5 STOPPING THE UI\IIT
Press the STOP pushbutton to halt tape motion
from any mode. The 280B automatically stops if
the tape breaks or end-of-tape is reached. This is
provided for by the tape-break ann, located on the
right side of the tape transport.
3.6 RECORD MODE
A. Thread the transport with a blank tape or
a tape previously recorded with program
material no longer required.
NOTE
If the previously recorded tape was
recorded with a different head config-
uration, best results are obtained by
bulk erasing the tape before recording.
B.
Set the Monitor switch to RECORD.
C.
Adjust record level with the RECORD LEVEL
control.
D. Set the Function switch to RECORD READY
for those channels to be used for recording.
E. Press the START push button to start tape
motion.
F.
Press the RECORD pushbutton. The indicator
lamp in the RECORD pushbutton lights (red),
but RECORD READY must also be selected
before the RECORD indicator on the amplifier
lights
and the transport enters the RECORD
mode.
3-1

3-2
Operation
Model 280B
TRANSPORT CONTROLS
1 POWER OFF/ON
2 RECORD
(RED)
3 TENSION
4
ATL DEFEAT LEVER
5
FAST REVERSE (BLUE)
6
FAST FORWARD (BLUE)
7 STOP
(WHITE)
8
START (GREEN)
9 CAPSTAN
LOW/HIGH
10
EDIT (YELLOW)
RECORD/PLAYBACK
CONTROLPAI\IEL
1 RECORD INDICATOR LAMP
2 FUNCTION SELECTOR SWITCH
RECORD
READY (RED)
SAFE (GREEN)
SYNC
(ORANGE)
3 RECORD/PLAYBACK MONITOR
MONITOR SWI TCH
4
PLAYBACK LE VE L
5 RECORD
LEVEL
6 VU METER
Figure 3-1. Controls and Indicators