Texas Instruments 990 - Page 134

Step
Symptom
Cursor Error 1
2
Cursor Error 2
3
Cursor Error 3
Table 2-13. Fault Isolation of Apparent Cursoir Address Problems
Probable Cause
CRU interface logic,
cursor address buff er,
cursor address register
Cursor command
decode logic
CRU interface logic,
cursor address buffer,
cursor address register,.
cursor command
decode logic
Troubleshooting Proceduire
Use CU-SL verb to con-
tinuously increment and
decrement.
Use CU-I verb to position
cursor and continuously
load selected address.
Use CU-A verb to position
cursor and CD-SL verb to
continuously increment
and decrement cursor
address.
Normal Indication
If Abnormal
Sync on NWOCRIOL
(U93-10 (U22-6 for
2nd controller)).
Examine CA, 0-10.
Syn1:; or NWlCRIOL
(U93--11 (U22-5 for
2nd controller)).
Examine CRB, 0-A,Q.
Sync on NWOCRlOL
(U93-10 (U22-6 for
2nd controller)).
Examine CA, 0-10.