Technical data

9050 Diagnostics 5-5
LEDs
Stack LEOs
• Directly controlled by stack boards.
• Lit for 112 second at start of Board Self-Tests (if a board occupies the slot).
• LEDs indicate stack board failure during board self-tests.
• LED corresponding to 1M byte RAM boards will blink during self-test.
• More than one LED lit; lowest number that is lit corresponds to the failed self-test.
• One LED lit; indicates failed board.
110 Card Cage LEOs
• Controlled by loader self-test program via SCM board.
• Loader self-tests turn on LEDs for 112 second at start of self-tests.
• Self-tests check 110 status lines for pass or fail. Failure of 110 channel, lights the corresponding
LED.
• Reset switch provides an error code for the failed card. Error code gives the same information
as message on display device. Reset switch toggles LEDs between failure
and 110 error code.
Status LEOs
Internal Bias (IB)
• Turned on when + 12 volt internal bias voltage is present (AC applied to main power supply).
• IB on indicates power applied to computer.
• 18 on indicates fuse is good.
• IB on indicates the computer is turned on
• 18 on indicates the interlock switch is engaged.
Power On ( + 5 Volt)
• Driven by + 5 volt power supply.
• Indicates main power supply is on.
• Off when power not available to main power supply (lB LED is off).
• Off during overtemperature condition.
• Off during over or under voltage condition (either main power supply or stack power supply).
Self-Test
• Turned on when board self-tests are initiated by SCM.
• Turned off after OS self testing is complete.
Load
• Turned on when boot loader code is loaded into RAM.
• Turned off after operating system is loaded and before control is transferred to the operating
system.
Run
• Controlled by SCM.
• Turned on after completion of OS self-tests.