System Status; Thermal Sensing And Cooling - HP Compaq dc7600 MT Technical Reference Manual

4.5.3 System Status

These systems provide a visual indication of system boot, ROM flash, and operational status
through the power LED and internal speaker, as described in Table 13.
d
.
System Status
S0: System on (normal operation)
S1: Suspend
S3: Suspend to RAM
S4: Suspend to disk
S5: Soft off
Processor thermal shutdown
Processor not seated / installed
Power supply overload failure
Memory error (pre-video)
Video error
PCA failure detected by BIOS (pre-video)
Invalid ROM checksum error
Boot failure (after power on)
Bad option card
NOTES:
Beeps are repeated for 5 cycles, after which only blinking LED indication continues.
[1] Repeated after 2 second pause.
[2] Beeps are produced by the on-board piezo speaker, NOT the chassis speaker.

4.5.4 Thermal Sensing and Cooling

All systems feature a variable-speed fan mounted as part of the processor heatsink assembly. All
systems also provide or support an auxiliary chassis fan. All fans are controlled through
temperature sensing logic on the system board and/or in the power supply. There are some
electrical differences between form factors and between some models, although the overall
functionally is the same. Typical cooling conditions include the following:
1. Normal—Low fan speed.
2. Hot processor—ASIC directs Speed Control logic to increase speed of fan(s).
3. Hot power supply—Power supply increases speed of fan(s).
4. Sleep state—Fan(s) turned off. Hot processor or power supply will result in starting fan(s).
The RPM (speed) of all fans is the result of the temperature of the CPU as sensed by speed
control circuitry. The fans are controlled to run at the slowest (quietest) speed that will maintain
proper cooling.
✎
Units using chassis and CPU fans must have both fans connected to their corresponding headers
to ensure proper cooling of the system.
Technical Reference Guide
Table 4-13.
System Operational Status LED Indications
PowerLED
Steady green
Blinks green @ .5 Hz
Blinks green @ .5 Hz
Off – clear
Off – clear
Blinks red 2 times @ I Hz [1]
Blinks red 3 times @ I Hz [1]
Blinks red 4 times @ I Hz [1]
Blinks red 5 times @ I Hz [1]
Blinks red 6 times @ I Hz [1]
Blinks red 7 times @ I Hz [1]
Blinks red 8 times @ I Hz [1]
Blinks red 9 times @ I Hz [1]
Blinks red 10 times @ I Hz [1]
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Beeps [2] Action Required
None None
None None
None None
None None
None None
2 [2] Check air flow, fans, heatsink
3 [2] Check processor presence/seating
4 [2] Check voltage selector, devices, sys. bd
5 [2] Check DIMMs, system board
6 [2] Check graphics card or system board
7 [2] Replace system board
8 [2] Reflash BIOS ROM
9 [2] Check power supply, processor, sys. bd
None Replace option card
System Support
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