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This section contains all alignment, adjustment, and
removal procedures
nece~ry
to maintain IBM 3277
Display Stations. It also contains service checks and
checkout procedures to determine whether adjustments are
required and to verify the accuracy of any adjustments
made.
5.1 CHECKS
5.1.1 Display Station Test Using Test Pattern 1
A comprehensive test of the display station and all attached
features is performed by using diagnostic Test Pattern
1
and
the procedures described in the following paragraphs. The
step-by-step procedures describe the sequence in which the
various operations should be performed and the results
expected of each operation.
The tests should be performed
in the sequence
presented, because each test is dependent on data left on
the screen from preceding tests. The observations described
in paragraph 5.1.1.1 apply to all display stations. Further
testing depends on what features are attached to the display
station.
If a problem is discoverect while performing this oper-
ational test, refer to the Symptom
I
ndex or the Trouble-
shooting Diagrams to resolve the problem.
5.1.1.1 Initialization and Observations
1. Load Test Pattern 1 on display station being checked.
(See paragraph 2.2.1 for instructions for loading Test
Pattern 1.) SYSTEM AVAILABLE is the only indicator
that should
be
on after pattern is loaded.
2. Take display station offline by removing control unit
signal cable. Jack is located at front of display station,
under front cover. Do not turn power off while
removing cable or Test Pattern 1 wi" be lost.
3. Compare image on screen with expected image shown in
Diagram 2-4. The "NON DISPLAY" field should
be
blank. Top two rows are displayed in normal intensity,
next two rows are displayed in high intensity, and half
of last row is displayed in high intensity.
4. Check for only one cursor. Cursor should be in first
character position of second row of displayed data.
5. Check quality of displayed image. Image should not be
tilted or blurred, and characters should be formed
properly with correct inter-row spacing.
6. Vary Brightness control. Set it where high intensity
characters have proper brightness.
Section 5. Checks, Adjustments, and Removals
7. Vary Contrast control. Set it where normal intensity
characters contrast with high intensity characters at
desired level.
5.1.1.2 Security Keylock Test (Optional Feature)
1. Turn security key off (vertical position). All data should
disappear from screen, INPUT INHIBITED indicator
should light, and cursor should remain displayed.
2. Turn security key on. Original data should reappear on
screen, and INPUT INHIBITED indicator should go out.
5.
1. 1.3 Tests from Keyboard (Optional Feature)
Press the RESET key. The display image should appear as
shown in Diagram 2-4, with the cursor located under the
character C in the second row of displayed data. No
indicators should
be
on.
1.
Key in the
row
of alphabetic characters and the one
space exactly as they appear in the row above. All
characters should enter correctly, and cursor should
move under I after Space bar is pressed.
2. Move cursor under C of CK in second row of displayed
data, using
~
(Right) key.
3. Press INS MODE key. INSERT MODE indicator should
light.
4.
Press
A
key. Field should now appear
A~K.
5. Press FIELD MARK key. (Use B key on Ope.ator
Console keyboard.) Field should now appear A;
~K
(AB£K).
6. Press C key. The data should not change, but the
INPUT INHIBITEQ indicator should come on (in
addition to the INSERT MODE indicator, which has
remained on.)
7. Press RESET key. Both indicators should go out.
8. Press DEL key. The C should disappear, and the field
should now appear
A;~ (AB~)'
9. Press
+-I
key (New Line). Cursor should move under C
character in fourth row of displayed data.
10. Enter the special characters as they appear in the row
above, shifting where required. Cursor should appear
under 0 character after last special character enters.
11. Enter the digits 0 through 9 and the characters, . - and
A as they appear in the row above. (On Data Entry
keyboards, use the , over
*
and . over $ keys to enter
the , and . characters.) The following results should
occur:
a.
Typewriter and Operator Console keyboards with-
out numeric lock feature - all characters should
enter.
Checks, Adjustments, and Remova..
5·1
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