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3.1
SYMPTOM
INDEX
USAGE
The Symptom Index lists trouble symptoms that could be
encountered on 3277 Display Stations and features. Illus-
trations that show both correct and incorrect display
images are also contained in this section. Use the Symptom
Index and illustrations as the first step in a systematic
method of resolving display station problems. The index is
divided into six major categories:
1. Display malfunctions.
2. Keyboard malfunctions.
3. Selector light-pen malfunctions.
4. Power malfunctions.
5. CPU error indications.
6. Operator identification card reader malfunctions.
Some categories are divided into subcategories, making it
easier to relate the trouble experienced to the correct item
in the index.
Beginning with 1A
1,
the first item that most
closely describes the display station trouble should be used.
Categories and specific items are identified by a one-, two-,
or three-letter/number code (e.g., 1 A 1, 2G, or 4) in the left
column of the index. The code specifies the entry point
into the Troubleshooting Diagrams in Section 4.
The right column of the Symptom I ndex specifies action
to take to remedy the display station problem. That
column directs the Customer Engineer to a section trouble-
shooting diagram sheet or specifies a logic card (or cards) to
change. When more than one card is listed, isolate the
failing card by card swapping from among those specified.
Change the failing card and return the others to stock. The
right column may also specify an adjustment procedure in
Section 5.
Diagrams 3-1 through 3-24 show both correct and some
incorrect display images. The symptom I ist refers to these
illustrations to aid in identifying display station symptoms.
As an aid to rapid repair, diagrams that show incorrect
display images also specify the repair action.
Section 3. SYmptom Index
3.2 DEVELOPING SYMPTOMS
Display station malfunctions should be isolated offline
unless the trouble occurs only when operating online
through the control unit to the host CPU. Failures of this
type are listed in Category 5 (CPU Error Indications).
Display station operations that require a formatted buffer
for failure symptoms to become evident are:
1. Selector light-pen operations.
2. Display intensity control (high intensity and non-
display).
3. Protected and numeric field operations.
4. Tab operations.
5. Erase input and erase field operations.
Test Pattern 1 contains fields that test these operations.
The test pattern may be loaded from the system as an RFT
or OL T. Symptoms that require a formatted buffer are
marked with an asterisk
(*)
in the Symptom Index.
Offline symptoms should be developed by performing
the following tl..'5t sequence after the I/O signal cable is
removed.
1. Turn power on. (Always begin from a power-on reset
condition.)
2. Test cursor move keys
--+,
t, ..t.,
+-,
~
,
~,
+-' •
3. Test CLEAR key.
4. Enter four or five characters.
5. Press Tab
(~)
key.
6. Press Backspace
(+-)
four times.
7. Enter four characters.
8. Press Backspace
(+-)
four times.
9. Press INS MODE.
10. Enter four or five characters.
11. Test DEL key.
Stop the test sequence and go to the Symptom Index
when the first failure occurs.
Symptom Index
3-1
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