OIS 140 series diagnostic LEDs

There are LEDs on the front of the OIS Master processor that indicate the status of the PROM diagnostics. There are also eight lamps on the CPU board that provide a detailed description of the error.

Front panel LED indicators

When LED 1 is off, it indicates a non-fatal error (drive or workstation is not powered on).
LEDS 1 2 3 4
 Error Description
0 0 0 1
 No slave on line, master will not IPL until at least one device is powered on.
0 0 1 0
 No disk in floppy drive and IPL from floppy was selected.
0 0 1 1
 SMD drive not powered on/ not on-line
0 1 0 0
 Hawk drive not powered on/ not on-line
0 1 0 1
 Run-time error, press Reset button
1 0 0 0
 CPU board error (7501 or 7684)
1 0 0 1
 Data Link board (7503 or 7504)
1 0 1 0
 Floppy/Hawk board (7502)
1 1 0 0
SMD (7505/7506) or Winchester board (7950/7653)
1 1 1 0
 Expanded memory board (7685)
1 1 0 1
 Software error (often damaged system volume)
1 1 1 1
 Parity error (7501) can be caused by failed voltage regulator also.

Internal LEDs on CPU board

CPU board errors:

Hex Code
 DL7-DL4
 DL3-DL0
 Description
10
 0001
 0000
 Data Bus Error
20
 0010
 0000
 MPE Bit does not flag parity errors
30
 0011
 0000
 NMI does not generate from parity error
40
 0100
 0000
 Main memory parity error
50
 0101
 0000
 Memory error, 1st read of read/write/read sequence
65
 0110
 0101
 CTC Time Out occured
75
 0111
 0101
 CTC priority error
80
 1000
 0000
 Memory error, 2nd read of read/write/read sequence
94
 1001
 0100
 Incorrect interrupt vector generated
a4
 1010
 0100
 No interrupts generated
b4
 1011
 0100
 Incorrect number of interrupts generated
c0
 1100
 0000
 Illegal PROM address error.

Data Link board errors:
16
 0001
 0110
 R/W Control registers error
36
 0011
 0110
 Cannot select a slave
46
 0100
 0110
 Cannot IPL a slave
56
 0101
 0110
 1-byte slave read error
76
 0111
 0110
 Data link time out doing block transfer
86
 1000
 0110
 No data link busy interrupt generated
96
 1001
 0110
 Data buffer parity error doing block transfer
a6
 1010
 0110
 Incorrect data found after block transfer

Floppy/Hawk board errors:
17
 0001
 0111
 R/W Control registers error
27
 0010
 0111
 IPL from floppy status error
47
 0100
 0111
 Cannot find track 0 on floppy
77
 0111
 0111
 No sector pulse interrupt
97
 1001
 0111
 Sector counter never indicates sector
18
 0001
 1000
 R/W Control registers error (Hawk)
38
 0011
 1000
 Drive select register error
48
 0100
 1000
 Hawk drive does not restore
58
 0100
 1000
 Restore takes greater then 500ms
68
 0110
 1000
 No interrupt on Seek Complete
78
 0111
 1000
 No sector pulse interrupt
88
 1000
 1000
 IPL from Hawk status error
98
 1001
 1000
 Sector counter never indicates sector 0

CMD/SMD or Winchester board errors:
19
 0001
 1001
 R/W Control registers error (SMD)
29
 0010
 1001
 Seek operation failed to cause interrupt
39
 0011
 1001
 Seek operation returned bad status
49
 0100
 1001
 Incorrect interrupt vector on seek
59
 0101
 1001
 Read operation failed to cause interrupt
69
 0110
 1001
 Read IPL sector returned bad status (Includes ECC error)
1E
 0001
 1110
 R/W Control registers error (Winchester)
2E
 0010
 1110
 Drive does not become ready
3E
 0011
 1110
 No seek interrupt on RTZ
4E
 0100
 1110
 Track 0 not set after RTZ
5E
 0101
 1110
 Timeout on IPL read
6E
 0110
 1110
 Status error on IPL read
7E
 0111
 1110
 Cannot find sector 0
8E
 1000
 1110
 Head/Select forced error
9E
 1001
 1110
 No seek interrupt on seek

There are other codes for software/configuration errors, and expanded memory board errors. They will be added here soon.

Back