Autonetics RECOMP II User manual

RECOMP
•
COMPUTER
S·E RV ICE
MANUAL
Autonetlce ~ Industrial Products
A DIVISION OF NORTH AMERICAN AVIATION . INC 3584 WILSHIRE BOULEVARD. LOS ANGELES 5. CALIFORNIA

RE
MPII
• • • • •
• • •
. ........... ...... ... .......... ... .....
• • •••••
• • •• •••
•• • •• •
COMPUTER
SERVICE
MANUAL
20 August 1959
Autonetlcs ~ Industrial Products
A DIV'ISION OF NORTH AMERICAN AVIATION, INC, 3584 WILSHIRE BOULEVARD, LOS ANGElES 5, CAliFORNIA
188

11
SYSTEM TESTER
REFER TO TEST
EallPMENT SERVICE
MANUAL PUB 508-T-9
TYPEWRITER
REFER TO INPUT-
OUTPUT SERVICE
MANUAL PUB 508-T-8
TYPEWRITER
ASSEMBLY
PHOTOELECTRIC
TAPE READER
ASSEMBLY
TAPE
READER
COMPUTER
REFER TO COMPUTER
SERVICE MANUAL
PUB 508-T -7
TYPEWRITER
POWER SUPPLY
AND CONTROL
DESK
CONSOLE
r-::I
L::J
REFER · TO INPUT-OUTPUT
SERVICE MANUAL PUB 508-T-8
RECOMP II System Block Diagram
DESK
COMPUTER
•
CONTROL CONSOLE
REFER TO INPUT-
OUTPUT SERVICE
MANUAL PUB 508-T-8
COMPONENT TESTER
REFER TO TEST
EallPMENT SERVICE
MANUAL PUB 508-T-9
NOTE : SYSTEM SERVICE MANUAL
PUB 508-T-6 CONCERNS COMPONENTS
ONLY WHEN CONNECTED TOGETHER AS
A SYSTEM.
RC7-183
508-T-7

PREFACE
This manual is 1 of a set of 5 published by Autonetics to provide main-
tenance information on the RECOMP II computer system.
System Service Manua~: Publication No. 508-T-6
Computer Service Manual: Publication No. 508-T-7
Input-Output Service Manual: Publication No. 508-T-B
Test Equipment Service Manual: Publication No. 508-T-9
System Refe rence Schematic s: Publication No .. 508 - T - 11
The block diagram of figure 1 illustrate s each system component and shows
its applicable service manual. In brief, the scope of each RECOMP II service
manual is as follows:
System Service Manual: This manual describes the general concept of
RECOMP II maintenance and provides operating instructions for checkout of
the computer system using the system tester and both manual and automatic
test routines. The goal of these system test procedures is to isolate mal-
functions to a specific operational area or system component.
Computer Service Manual: This manual describes the operational com-
ponents located.in the computer assembly, including memory unit, power
circuits, and signal circuits. It also provide s maintenance instructions and
adjustments for computer components, and gives a detailed set ,Of test pro-
cedures for computer circuit boards using the component tester.
Input-Output Service Manual: This manual describes the operational
characteristics ·of RECOMP II input-output equipment (control console, type-
writer, tape reader, and tape punch). It also provides maintenance and test
instructions for these input-output devices and the associated desk assembly.
Test Equipment Service Manual: This manual describes the functional
characteristics of the system tester and component tester. It also provides
maintenance and test instructions for these two RECOMP II test equipments.
System Reference Schematics: This publication provides a set of
schernatics, assembly drawings, wiring charts, and signal charts for each
system component; i. e., computer, desk, control console, tape reader,
typewriter, and tape punch.
508-T-7
- iii -

Preface
Introduction
General
Operational Characteristics
Power Requirements .
Physical Characteristics
Functional Description
General
Memory
Power Circuits
Signal Circuits
"
Trouble Analysis and Adjustments
, , '
General
Memory
Power Circuits
Signal Circuits
General Maintenance Information
CONTENTS
,Removal and Replacement of Components •
Computer Connector Signal Chart
Circuit Board Connector Signal Charts .
-
iv -
Page
iii
I
I
I
2
2
4
4
4
12
22
42
42
45
53
63
96
96
100
100
50B-T-7

Figure
1.
2.
3.
4.
·5.
6.
7.
B.
9.
10.
lL
12.
13.
14.
15.
16.
17.
lB.
19.
20.
21.
22.
23.
24.
25.
26.
27.
2B~
29.
30.
31.
32.
33.
34.
35.
36.
37.
3B.
ILLUSTRATIONS
RECOMP II System Block Diagram.
Computer As sembly. Exterior Views
Computer Assembly. Interior Views
Cross-Sectional Diagram of Magnetic Memory
Air Thrust Bearing Diagram.
Write Head Construction .
Flux Diagram of Perpendicular Recording.
Read Head Construction Diagram
Reading of Perpendicularly Recorded Digits
Waveforms in Writing and Reading .
Permanently Recorded Clock Track Waveform
..
Head Positions on Magnet Disk (Systems 501 through 520)
..
'.
Head Positions on Magnet Disk (Systems 521 and Subsequent) .
Simplified Power Control Schematic.
Power Control Circuits Block Diagram
-100- Volt Power Supply B'lock Diagram
-lB- Volt Power Supply Block Diagram.
-12-Volt Power Supply Block Diagram
-6- Volt Power Supply Block Diagram
75- Volt Power Supply Block Diagram
6-Volt Power Supply Block Diagram
O. 75-Volt Power Supply Block Diagram
..
Location and Color Coding of Computer Etched Boards, Panel
Assembly No. 1.
Location and Color Coding of Etched Boards Panel Assembly
No.2.
Clock Circuit Waveforms and Approximate Voltages.
Clock Boards No. 1 and No. 2 Block Diagram.
Typical Diode" And" Gate Schematic
Typical Diode II And-And" Gate Schematic .
Use of IIAnd-Or" Gates in a .1- Word Arithmetic Register
Typical" And-Or
ll
Gate Schematic
Flip-Flop Block Diagram.
Read Switching Network Block Diagram .•
Read Amplifier Block Diagram .
Write Circuit Block Diagram.
Write Head Selection Matrix . ..
Loop and Register Write Amplifier Block Diagram
Information Channel Write Amplifier ·Block Diagram
Etched Circuit Board Extractor .
50B-T-7
Page
ii
. 2
3
5
6
6
7
8
9
9
10
11
12
13
16
17
18
19
20
21
21
22
23
24
26
27
2B
29
30
31
32
34
35
36
37
:39
40
45
-·v -

ILLUSTRATIONS (Cont)
Figure
39. Clock Wave Shape
40. Origin Wave Shapes
41. Strobe for Normal Pulse
42. Strobe Setting for Wide Pulse with Some Jitter
43. Read Switching Network Adjustment Points
44. Oscilloscope Template for Write Switch Checkout
45. Calibration Template, Clock Board No.1,
Outputs 1 and 2
46. Calibration Template, Clock Board No.1,
Outputs 3 and 4
47. Calibration Template, Clock Board No.1,
Output 5
48. Calibration Template, Clock Board No.2,
Pulse Output .
49. Use of Etched Circuit Board Extractors
50. Computer Connector Signal Chart .
51. Circuit Board Connector Signal Chart No. 1
52. Circuit Board Connector Signal Chart No. 2
53. Circuit Board Connector Signal Chart No. 3
54. Circuit Board Connector Signal Chart No. 4
55. Circuit Board Connector Signal Chart No. 5
56. Circuit Board Connector Signal Chart No. 6
-
vi -
Page
47
47
52
52
73
79
88
91
92
95
99
103
104
105
106
107
108
109
508-T-7

TABLES
Page
1.. Internal Test Points
43
2. Channel Selector Flip-Flop Settings for Main
Memory Gain Adjustment
48
3. Flip-Flop TI and Preamplifier Connections
50
4. Channel Length Indications
51
5. Pulse Coincidence 51
6. Power Supply Voltages
54
7. Power Transformer Voltages
54
8. Gate Selector Positions
64
9. Clamp Diodes Test
68
10. Individual Diodes Test .
69
11. Individual Resistors Test 70
508-T-7
-vii-

INTRODUCTION
GENERAL
This manual provide s a de scription of the operational components
located in the computer assembly, including memory, power circuits, and
signal circuits. It also provides maintenance and repair instructions for these
components, including detailed test procedures for the etched circuit boards
using the component tester. In most cases, the functional tests described in
the RECOMP II System Service Manual must be performed before the instruc-
tions contained in this manual are used.
OPERATIONAL CHARACTERISTICS
The RECOMP II computer (figures 2 and 3) is a general purpose digital
. computer that utilizes the binary number system for all internal operations.
The input equipment used to address the computer consists of: photoelectric
paper-tape reader, electric typewriter, and control panel keyboard. Output
equipment include s visual readout via the control panel, typewriter, and
teletype -coded paper -tape punch.
The computer memory is a rotating magnetic disk. It has a capacity of
4080 nonvolatile words plus two 8-word, rapid access loops. Nonvolatile refers
to the fact that even during power interruptions the disk retains the recorded
information. Also on the disk memory unit are the permanently recorded timing
tracks (clock and origin), and five I-word arithmetic registers.
A RECOMP word consists of 41 binary digits. One digit is used for a
synchronizing bit and is not available for programming. A word can either be
a number (sign plus 39 significant digits) or a command. (In actual operation,
there will be 2 commands to 1 word.)
There are five basic types of commands in RECOMP II: arithmetic,
transfer (conditional or unconditional), store, interchange, and input or output.
ACCESS TIME
Access time for main information channels is 0.52 millisecond minimum.
and 16.9 milliseconds maximum. Access time for the high-speed loops is 0.95
millisecond maximum for reading and 2.34 milliseconds maximum. for writing.
OPERATION TIME
Operation time (excluding access time) for addition or subtraction is O. :52
millisecond. Multiplication and division require 10.4 milliseconds (exclt:j.ding
access time.) Transfer control requires 0.78 millisecond.
508-T-7
- 1 -

POWER REQUIREMENTS
The power requirements for the computer are 115 volts, 60 cps, single-
phase at 400 watts (excluding input/output equipment.)
PHYSICAL CHARACTERISTICS
Size: 23 inches wide, 21 inches long, and 16.5 inches high (excludes
input/output equipment)
Weight: 196 pounds (excludes input/ output equipment)
Structure: Welded aluminum (steel in later models)
Finish: White. cocoa brown. madrone. and pale straw gold enamel (or anodize)
.
~~=;- _ +- ___ 1 --TYPEWRITER AND
TAPE PUNCH CONNECTOR
(J23)
COMPUTER REAR VIEW
CONSOLE
C ONNECTORS (J24 ,
J25, J26, J27 )
, -;;;- _oCOMPUTER MAIN POWER
CONNECTOR (J28)
Figure 2. Computer Assembly - Exterior Views
RCI-I79
- 2 - 508-T-7

POWER SUPP L Y
AND CONT R OL
r. IRCUI T l>U' AR~S --,
SYS TE M
T
EST ER
JAC KS
508-T-7
POWER } Kl K2
CONTROL KS' K6'
RELAYS .
INTERLOCK SWITCH S2
POWER TRA NSF ORM ER
K3. K4
POWER CON TROL
RELAYS
Fig u re 3.
Computer Assembly - In t e r ior View s
J6
17
J8 SYSTEM
J9
no
TESTER
JAC KS
(CHOKES)
MEMORY
CONNECTORS
RC I-177
- 3 -

FUNCTIONAL DESCRIPTION
GENERAL
This section describes mechanical and electrical functional characteristics
of operational components located in the computer assembly.
The computer central framework houses a magnetic disk memory, second-
ary power supplies, and two blowers. Hinged to both sides of the central frame-
work are castings that form the sides of the computer, and mounted on the
outside of these castings are all etched circuit boards except power supply
circuit boards. The inside of each casting supports the interconnecting wiring
for the circuit boards. Receptacles for the system tester connectors
mounted on the unhinged ends of each casting.
MEMORY
The RECOMP II memory consists basically of a magnetic disk rotating
past fixed read and write heads. Information is stored on the disk in the form
of flux patterns representing binary digits. When the disk is rotating, an air
bearing provides an air gap of approximately 50 microinches between the record-
ing surface of the disk and the read and write heads.
MECHANiCAL OPERATION
Principal parts of the memory assembly are illustrated in figure 4. A
flexible diaphragm attaches the disk to the rotor. The rotor is mounted to a
nonrotating shaft with ball bearings held in place by snap rings. The shaft is
supported by 2 parallel diaphragms, I located in the inner edge of the 'head-
plate and I in the lower part of the frame. The solenoid coil is contained
in a housing fixed to the frame. The solenoid plate (armature) is m.ounted to
the lower end of the shaft. The shaft is spring -loaded between the solenoid
plate and solenoid housing collar. Untill power is applied to the solenoid, the
shaft is held at its lowest extremity by"the spring. Information can neither be
written on nor read from the disk because of th,e separation between disk and
headplate when the shaft is in this position. The shaft is held at its lowest
extremity while the disk motor is run up to speed. The motor is a split-phase
induction.:.type incorporating a capacitance start with an operating speed of 3450
revolutions per m.inute. When the m.otor and disk reach operating speed, the
solenoid is energized and forces the shaft toward theheadplate against the
preloaded spring.
- 4 -
508-T-7

Because the shaft, rotor, and disk move as a single body, the disk is forced
near the headplate (approximately 50 microinches). Information can now be
stored and extracted.
In operating position, an air thrust bearing maintains the spacing between
the rotating diskCl-nd the headplate. The air bearing consists of eight grooved
radial sections, the configurations of which are 45 degrees each (8 x 45 == 360
degrees) in. width around the circular surface of the headplate (figure 5). As
the disk rotates, air moves in the direction from A to E, expanding in the
grooved sections and compressing in the flat sections. Any tendency of the
disk to touch the headplate is offset by the pressure of the air 'at compression
points .
. READ AND WRITE HEADS
Magnetic read and write heads are used for recording information on and
reproducing information from the magnetic disk. They are mounted in slots in
SliAFT .. DlAPHRAGM
SOLENOID HOUSING
SOLENOID COIL
--"~"';L'UA1}J:;1J SPRING
NONROT."TING SliAFT
Figure 4. Cros s-Sectional Diagram of Magnetlc Memory
HEADS
CONNECTOR
RCl-10l
508-T-7 -5 -

DISK MOTION
HEADPLATE
; RCl-olS3
Figure 5. Air Thrust Bearing Diagram
the headplate. The write head (figure 6) consists of (1) a centertapped coil of
copper wire, (2) a metal core formed of thin, high-permeability T-laminations,
(3) two fairly high permeability, low-loss magnetic blocks, and (4) ceramic
inserts. Th.e pole tip which consists of the edges of the laminations provides
the writing area.
Information is written on the disk "perpendicularly," as diag~ammed in
figure 7 ... When the coil is energized, flux concentrates at the end of the pole
tip and enters the iron oxide recording material. Because this material is of
CERAMIC
·INSERT
Figure 6. Write Head Construction
CERAMIC INSERT
POLE TIP
- 6 - 508-T-7

low permeability as compared to that of the backing material, the flux does not
spread out. It flows downward, setting up vertical magnets in the iron oxide,
and then enters the high-permeability backing material. Here it spreads out,
then reenters the recording medium. Completion of the flux path takes place
through the magnetic blocks and back to the center leg of the T-laminations.
The demagnetizing effect of the return nux on the magnets already produced is
very slight because the return flux is highly diffused.
Current through the write head is in the form. of square wave pulses flowing
through one-half of the coil toward the center tap for a binary-l signal and·
through the other half toward the center tap for a binary-O signal. This type of
recording is termed "nonreturn to zer::>" because the recording current is
either at a negative or positive level but never at zero level. The flux pattern
induced in the recording medium is shown in figure 10. Positive square wave
inducing pulses are magnetized as square waves with rounded corners, that is,
lesser intensity at the leading'and trailing edges.
The read head (figure 8) cO<1.sists of (1) a single-ended coil, (2) a metal
core formed of T-laminations, and (3) two fairly high-permeability, low-loss
magnetic blocks shaped to form a shielding extension near the pole tip. In
reading, the read head senses only the changes in the magnetized state of
the recording material. Essentially triangular voltage pulses result
POLE
LAMINA TIONS
COIL
HIGH
PERMEABILITY
BACKING
MATERIAL
TO WRITE SIGNAL
POWER AMPLIFIERS
MAGNETIC
BLOCK
LOW
PERMEABILITY
RECORDING
Figure 7. Flux DiagraITl of Perpendicular Recording
RCl-l51
508-T-7 - 7 -

COIL
POLE TIP
RCl-l~9
Figure 8. Read Head Construction Diagram
from the reading. a positive pulse representing a change from binary 0 to binary
1 and a negative pulse representing a change from binary 1 to binary O. For a
succession of similar binary digits, the first digit is reproduced as a pulse and
succeeding digits have a 0 -volt level. The magnetic block extensions at the
base shield the coil from adjacent recorded digits, thereby permitting only one
digit pattern at a time to be read. (See figures 9 and 10. )
ERASE HEADS
The erase heads are similar to the read and write heads in physical dimen-
sions and appearance. The difference is that the erase heads have a permanent-
magnet wire along the center instead of a T -type pole piece with coil. The magnet
wire is now the central pole piece. Magnetic lines issuing from this pole piece
return through the magnetic blocks, as for the read and write heads. The
strength and polarity of this magnetic field is such that all changes of flux are
removed from the disk as it passes under the erase heads.
CHANNELS
The memory disk is divided into channels which consist of concentric
tracks 0.025 inch wide and separated from each other by 0.015 inch. The
channels are utilized as follows:
- 8 -
508-T-7

HIGH PERMEABILITY
BACKING MATERIAL
TO RE.,.D SIGNAL
PREAMPLIFIER
MAGNETIC BLOCK
(SECTIONAL VIEW)
DIGIT BEING READ
Figure 9. Reading of Perpendicularly Recorded Digits
1. Sixty-four permanent- storage information channels, which store 64
words per channel. (The channels are identified by read heads numbered
octally MO through M77 and corresponding write heads numbered octally W0
through W77' Channel 77 contains only 48 addressable word spaces because the
last 16 addresses are assigned to the rapid-access loops L and V, loop L having
the addresses 7760 to 7767, and loop V having the addresses 7770 to 7777.
2. One clock channel (C) which contains permanently recorded sine
waves (figure 11) for synchronization of computer circuits.
508-T-7
BINARY
DIGIT
WRITE
CURRENT
FLUX
PATTERN
READ HEAD
VOLTAGE
o
Figure 10.
o o o o o o o
Waveforms in Writing and Reading
- 9 -

3. One origin channel Xor which contains a permanently rec;:orded pulse
for initial synchroni~ation of computer circuits and for resetting the digit
counter.
In addition, one channel provides storage space for the following loops
and registers:
1. Four recirculating I-word ·arithmetic registers (accumulator A, num-
ber register B, r.emainder register R, and auxiliary register X).
2. One reCirculating I-word control register (command register Z).
3. " Two high-speed 8-word recirculating loops (L and V), which can copy
and store any 8 consec\1tive words from any of the 64 information storage
channels, An additional read head i.s located four words from the ':IVrite head
on channelsL and V. This head provides acce,ss to information stored between
the read and write heads on the 8-word loops, thereby reducing the access time
for re,adout.
Each channel, register, and loop has a read head and write head. (See
figure 12.) The read heads are separated from the write heads by 180 degrees
for the information channels, clock channel, and origin channel. On the outer-
most channel. the read and write heads are spaced approximately I-word
length for the I_word A. •. B. R. X, and Z registers. The read and write, heads
are spaced at 8-word lengths for the L and V loops with an additional read head
spaced at 4-word lengths. A permanent magnet erase head on the outermost
channel. which contains the recirculating registers and loops. separates the end
of each register or loop from the start of the next. By this location of the erase
head. information read from one register is erased before the same area of the
disk passes under the write head of the next register.
DISK MOTION"-..--_.._..,
- ..
Note: Clock channel contains 26Z4
magnetized sine wave cycles,
41 cycles per word sector
Figure 11. Permanently Recorded Clock Track Waveform
.; 10 - 508-T-7

LEGEND:
l-WORD REGISTERS: B, X, R, A, Z
a-WORD REGISTERS: L, V
64-WORD CHANNELS: MAIN MEMORY
CHANNELS NUMBERED OCTALLY 0 TO 77,
CLOCK CHANNEL (C), ORIGIN CHANNEL (~OR)
M = MAIN MEMORY READ HEAD
W = MAIN MEMORY WRITE HEAD
SUBSCRIPT R = READ HEAD
SUBSCRIPT W = WRITE HEAD
ERASE = ERASE HEAD
RCl-.lOO
Figure 12. Head Positions on Magnetit Disk (System s 50l'through 520)
The placement of the heads illustrated in figure 12 is applicable only to the
memories originally installed in systems 501 through 520. Figure 13 shows
the hea~plate design for systems subsequent to 520, wherein the channels are
"pushed out" to provide for a greater diameter, and thus a greater circumfer-
ence, for the inner tracks.
This greater circumference reduces the pos sibility of the origin pulse
being too wide in terms of duration and also reduces the possibility of amplitude
modulation occuring on information stored in the inner channels. Principles
of operation, however, are the same as previously described in this sectioh,
and all connection details and logic details are the same for both headplate
c onfigu ra t ion s.
Memories with this "push out" design may eventually replace those now
installed if replacement is warranted under normal operating conditions.
508-T-7
- 11 -