From: Peter Hsieh (p-hsieh@northwestern.edu)
Date: Tue Oct 05 2004 - 13:26:23 EDT
A few days ago one of the J5600's in the lab shut down with a fan error
message. The LCD on the front of the machine indicates that fan 6, the
right CPU turbocooler fan, was at fault. Upon removal of the side
panel, I found that the fan was difficult to spin, possibly due to dust
buildup. (The left CPU0 fan, in contrast, was easy to spin.) The
service manual indicated that the entire system board tray assembly
should be replaced. As HP has discontinued the Visualize J5xxx line
(and the system is not under a service contract), I attempted to replace
the bad fan on my own. The repair failed. I am trying to determine why
it failed and what I should do.
I obtained a Panaflo DC brushless fan (Model FBA06A12H, DC 12V 0.22A) in
muffin fan configuration and reshaped the plastic to fit the geometry of
the HP turbocooler heat sink. I had to solder the HP connector wires to
the new fan (+ to red, - to black, and S to yellow). The new fan is an
exact fit for the bad fan in the turbocooler housing (which is just a
piece of machined metal). I attached the repaired fan to CPU1 with
PC-grade thermal paste and screwed the entire assembly into the system
board.
When I turn on the system power, both CPU fans spin up. However, the
system powers itself down after approximately 30 seconds without
warning. Disabling CPU1 makes no difference. The system shuts down
whether it is booting or in diagnostic mode. Interestingly enough, if I
unplug the chassis fans from the system board, the system will go all
the way through the boot-up process to the GUI log-in screen before
shutting itself down with fan error messages. I suspect that there is
something wrong with the fan monitoring hardware or software, but I am
not sure what I should do to resolve the problem.
Questions:
1. Has anyone replaced a CPU turbocooler fan on a Visualize
workstation? If so, where did you find the turbocooler? (Apparently HP
dumped a large number into the PC overclocking market in '99, but no one
is selling them now.) What kind of thermal compound did you use? (The
HP compound is hard, unlike the PC thermal pastes on the market.)
2a. Assuming the fan is good, what can I do to test the fan control
electronics? I am guessing that there is some process from the firmware
that monitors fan status and triggers a shutdown if the fan is outside
tolerance (voltage, rpm, etc.) I went through the diagnostic menus but
found nothing that would let me poll the fan status directly. Is there
any way of overriding the monitoring daemon short of doing something
drastic to the firmware?
2b. If the problem is a faulty fan controller board (per J. Fletcher in
[HPADM] [SUMMARY] "bad fan 3" warning on a J6000), is it something I can
replace, or do I need to call HP?
3. If there is no other way to fix the problem other than to replace
the entire system board tray assembly, what's the easiest way to move
data off of the system? Can I just remove the hard disk, plug it into
the drive bay of another J5600, and mount it?
Thanks in advance for any insight you may have on how I can resolve this
problem.
Peter Hsieh
Northwestern University
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