AlphaServer 4100 CPU fan

Jon Elson elson at
Mon Jul 20 10:17:43 CDT 2015

On 07/20/2015 09:23 AM, Adrian Graham wrote:
> Folks,
> I didn't realise there'd been a clasiccmp server meltdown, wondered why I
> wasn't getting mails :)
> We still have a few AS4100s out there in the field and CPU fans are
> becoming scarce, so being canny we sourced some *almost* identical
> replacements to no avail.
> Original spec for the fan is 12V 0.17A, our replacements are 12V 0.18A and
> the console still reports them as failed. I've sanity checked by using a
> processor board with a good fan and still nothing. Could the 0.01A cause
> THAT much of an issue? The wiring is a good 3" longer too but I didn't
> think that would cause problems either.
Do the original fans have speed sensors?  There were several 
different versions of this.  Some fans have an OK signal, 
some give a pulse once per rev.  Did the original fans have 
3 wires?


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