Technical data

General Failure Indications
Table 4-1. Self-Test LED General Failure Indications
Failure Indications
via Upper Two LEDs
State Indication Only
Required Device Missing or
DTACK Failure
Failing Device
LED Pattern
General Description of Failure
ooss ssss,
Where ss ssss Indicates State of
Power-up
o.dd dddd,
where dd dddd Indicates Device
.odd dddd.
where dd dddd Indicates Device
Special
Codes ••••••••
(Special Case Highest Priority Codes) LEDs Never Accessed
(or
Unused Code)
State or Device Codes
Via Lower 6 LEDs
Miscellaneous (Highest Priority)
Internal Peripheral Failure
(Medium
Priority)
I/O Failure
(Lowest Priority)
30 Troubleshooting
0 •••••••
LEDs Failed to DTACK
0000 0.0.
Timer on processor board has failed
or is missing.
LED Pattern
General Description of Failure
xxoo ffff
Where ffff indicates
Failure (xs are
don't-care bits)
xxo. pppp
Where pppp is Peripheral Number
xx.s ssss
Where s ssss is Select Code