8642 Common Devices



Front Panel



720 Status LEDs and Information Panel

Status LEDs
Green = proper operation  Yellow = alert condition

LED#
Definition 
Hard disk drive activity 
DASD error 
Processor Complex Error 
Color green (POWER GOOD) 
Color green (POWER Enabled) 
Color green (All subsystems good) 

Error Codes
Corollary Errors (CP,TP,EP,IP,FP,HALT)
PCI Errors  (DDDD DD S 0 VVVV IIII) 
General Errors

Liquid Crystal Display 
  The Liquid Crystal Display (LCD) on the front operator panel contains a 2-line by 16-character LCD (front panel display) driven by the 80C752 microprocessor. The front panel display receives and transmits ASCII characters. The LCD supports the upper-and lower-case ASCII character set.
   Errors detected by the computer might be displayed on the LCD and/or on the standard display attached to the computer. This is helpful when a display is not attached to the computer or the attached display is inoperative. 

LEDs - System Board and Adapter 
   LED(s) are located on planar, bridge, processor, and memory card. 

Component  LED On LED Off 
Planar Slot LEDs: B1 (bridge card slot) During / after normal initialization of bridge card  -SW problem preventing initialization of card 
-Defective LED 
-Defective bridge card 
M1 
(memory card slot)
During initialization of memory card Successful initialization of memory card complete 
M2/P1
(w/ memory card installed)
During initialization of memory card  Successful initialization of memory card complete 
M2/P1
(w/ processor card installed)
During initialization and activity on processor card - No activity on processor 
- SW problem preventing initialization of card 
- Defective LED 
- Defective processor card 
P2 thru P6 
(with processor card installed)
During initialization and activity on  processor card -No activity on processor 
- SW problem preventing initialization of card 
- Defective LED
- Defective processor card 
Micro Channel slots When computer is powered-off  When computer is powered-on 
Bridge card LED During / after normal initialization of bridge card - SW problem preventing initialization of card 
- Defective LED 
- Defective bridge card 
Memory card LED(s) During initialization of memory card Successful initialization of memory card complete 
Processor card LED(s) During initialization and activity on processor card -No activity on processor -SW problem preventing initialization of card 
-Defective LED 
-Defective processor card 



I²C (Inter-Integrated Circuit)
   The I²C (Inter-Integrated Circuit) bus is a serial bus that is used in the PC Server 720 to monitor and control several peripheral functions within the machine. The bus is driven through a VLSI module on the system board. A service processor on the system board (based on the Intel 83C552 micro-controller) controls and monitors these functions within the machine through the I²C bus. These include: 

      The front panel LCD 
      The front panel power controls 
      Detecting the setting of the SCSI ID jumper on the hot-swap backplanes 
      Reading the voltage and temperature sensors on the planar (viewable using NetFinity) 
      Controlling the three fans mounted behind the drive bays 



 

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Ardent Tool of Capitalism - MAD Edition! is maintained by Tomáš Slavotínek.
Last update: 27 Feb 2021 - Changes & Credits | Legal Info & Contact