Disassembly And Assembly; Access To The Display Unit Circuitry; Keyboard Information - Tektronix 4010 Maintenance Manual

Block Diagrams and Circuit Diagrams. These diagrams
and their associated descriptions provide an understanding
of Terminal operation on a circuit as well as component
level. The information contained therein is essential to
efficient location of trouble.
Component Layout Illustrations. These appear in the
Diagrams section and can be used as aids for locating
components.
Interconnecting Wire Lists. A listing of cables, jacks and
plugs, as well as an explanation of their use, is provided at
the beginning of Section 6. Wire colors are also provided,
using the standard code for resistors.
Semiconductor Information. An illustration of semi-
conductors appears near the beginning of the Diagrams
section, and can be used for pin identification. An
integrated circuit test clip is recommended for use in
troubleshooting the in-line integrated circuits, since it
makes their leads easily accessible.
Troubleshooting Procedure
To troubleshoot the basic Terminal, remove all accessory
cards and the interface card. Then check operation by
doing the Performance Check. Stop where the Terminal
fails to respond properly, and troubleshoot the referenced
area, using block diagrams, schematics, and associated
descriptions. Replacement of suspected circuit cards is
recommended as a fast means of confirming suspicions. If
the Performance Check works satisfactorily in the basic
Terminal, install option cards and the interface card one at
a time and repeat the Performance Check until it fails. Then
troubleshoot the last-inserted option card and the circuits
with which it interacts.
Obviously, not all troubles can be high-lighted by the
Performance Check or Calibration Procedure. However,
they should prove beneficial in most cases, and should go a
long way in guiding a technician to the trouble area.
Recommended Troubleshooting Equipment
A Logic Extender Card, TEKTRONIX Part No.
067-0653-00, is an efficient tool for circuit analysis. This
card can be used as an independent plug-in card to make all
minibus signals available to the Technician, providing level
indicators for most of the lines. In addition, it provides a
feature for injecting high or low level logic signals into the
signal lines. The card can also be used as a extender for
other circuit cards, and then permits interruption of any or
all signals to the card wh ich is attached to it.
REV. C, APR. 1976
Servicing-4010 Maintenance
Another extender card is available under TEKTRONIX
Part No. 067-0664-00. This card can be installed into the
minibus to make bus lines available at test points, and can
also be used as an extender for cards installed in the
minibus.
A -15 V to +400 V DC voltmeter and a 10 MHz
frequency response oscilloscope are recommended test
equipment for troubleshooting low-voltage and logic
circuits. A -4000 V DC meter is required for trouble-
shooting the high voltage circuits.
I
WARNING
I
Dangerous voltages exist within the pedestal and
display units. Normal electrical safety precautions
should be observed at all times when working around
exposed circuits within these units.
When troubleshooting the power supply circuits, a
resistive dummy-load should be connected in place of the
Terminal circuits. This avoids accidental damage to other
circuits in the Terminal. Recommended loads are as
follows:
Power Supply Connector Load
+15 V J70
30
n,
15 W
-15 V J73 30
n,
15 W
+5V J72 1
n,
50 W
DISASSEMBLY AND ASSEMBLY
Access to the Display Unit Circuitry
For access to the circuits within the display unit, remove
the three screws at the top of the rear surface. Then lift the
top panel up and forward.
The high voltage shield must be removed to obtain
access to the majority of the circuits on the High Voltage
and Z Axis circuit board. To remove it, first remove the left
side panel (as viewed from the front!. Then remove the
three screws from the shield. Lift the shield out the side of
the unit.
Keyboard Information
Perform the following procedure to get at the keyboard
circuits:
(1) Remove four screws from underneath the front
of the keyboard.
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