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I
N
N
Table 4-2.
Symptom
13. The parity error sym-
bol is the only char-
acter displayed in. the
receive mode.
Digital Circuits, Symptom Troubleshooting Chart (Continued)
b.
c.
Check Procedure
On the display, the characters
K, F, and 5 are painted in char-
acter slots one, two, and three of
the first line.
Connect an oscilloscope probe to
pin 8 of Al2 and repeat
step~.
Observe a level change on the
scope.
Connect an oscilloscope probe
to pin 61 and a second probe to
pin 3 of A12.
Sync the scope
from pin 61 of A 12 and repeat
step a.
Send the character K
aboutl0 times.
Repeat step 12.
Co rrective Action
If the level does not change,
replace the A14 board.
If the level does change.
perform check.£.
If the presentation on the
scope is correct, replace
Al3.
If neither level changes,
replace the All board.
If the display presentation is
correct, the trouble is not in
the Display Terminal.
If the
presentation is incorrect.
repeat step 7b.
If the
0A
clock pulses are 833 ::1::10
!-L
s
apart, replace the AIZ board.
If not, adjust
Rl6 on A 14.
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