Tektronix 4010 Maintenance Manual page 113

GENERAL INFORMATION
Introduction
The description of Terminal concepts and circuit oper-
ation is separate from the block diagrams and circuit
schematics. This allows the reader to have the diagram
available while reading the. text. When troubleshooting,
select the proper schematic diagram for the board number
installed in your instrument. Assembly numbers (Ax) on
the schematic diagrams and the board numbers (670-0000-
00) are a guide to the parts listing for the board in the
Electrical Parts List. Assembly numbers are also given on
the Connector and Wiring Diagram Fig. 6-1.
This section also contains a Wire List, and a Dictionary
of Line Titles that will prove beneficial in understanding
logic flow on the Interconnection Mother Board (minibus).
A Wire List Explanation shows how to use the Wire List in
conjunction with the Connectors and Wiring Diagram (Fig.
6-1) and the Interconnecting Mother Board diagrams. The
Dictionary of Line Titles should be read before any of the
block diagram or circuit descriptions. The Wire List Expla-
nation should be read before attempting to trace signals
between schematics.
Diagrams and Circuit Description Information
The circuit descriptions with the block diagrams and
schematics will allow those not familiar with 4010 oper-
ation to progress from a basic understanding to a fairly
detailed understanding of 4010 concepts and operation. It
is recommended that those unfamiliar with 4010 operation
read the following block diagrams and their respective
descriptions in the following order.
1. Terminal/Computer Communication Concepts. This
block diagram (on DATA FLOW tab) with its description
will acquaint you with the basics of Terminal/computer
operation. It will also introduce for the first time the basic
electrical sections of the Terminal, namely, Keyboard,
Terminal Control Logic and the Display Unit.
2. Terminal Data Flow Block Diagram and Description.
This block acquaints you with the basic data flow within
the 4010. It shows the tie-in of the major electrical com-
ponents for the Alphanumeric Mode, the Graphic Plot
Mode, and the Graphic Input Mode.
REV. C, APR. 1976
Circuit Description-4010 Maintenance
3. Alphanumeric Block Mode Diagram and Description.
This block shows the operation and logic tie-in of TC-1 and
TC-2 in the Alpha Mode.
4. Graphic Modes Block Diagram and Description. This
block provides the logic tie-in of TC-1 and TC-2, for
Graphic Plot and Graphic Input Mode operation.
5. Display Unit Block Diagram and Description. This
block diagram and description gives a basic understanding
of the circuitry associated with the Display Unit.
The above block diagrams and associated descriptions
will, in most cases, aid in isolating a problem to a specific
circuit card. Should you desire to further isolate the
problem they will provide you with enough information as
to where to go next.
DICTIONARY OF LINE TITLES
General
The following is a description of interconnecting (mini-
bus) signals and the explanation of their purpose and
operation. Signals are shown in their active states. Those
with bars indicate that the source must pull the signal line
low to be active. Those without bars indicate that the
source must pull the signal line high to be active.
Data to and from the Terminal/
computer.
Indicates data is to be sent as a full
8-bit byte (do not add parity).
Means data is about to be sent to
the minibus by the computer
(Interface). Must be sent at least 5
microseconds before data is placed
on BIT1-8 lines and must remain
low until after the trailing edge of
the strobe(s) associated with the
transfer.
6-1