AlphaServer 4100 CPU fan

[Johnny Billquist]

On 2015-07-20 17:31, Adrian Graham wrote:
> Hi,
>
>> 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?
>
> Yes, I put them down as +12V, GND, Pulse.
>
> Original fan: http://f0p.co.uk/AS4100original.JPG
> Replacement: http://f0p.co.uk/AS4100replacement.JPG
>
> I'm guessing the original was slightly more 'special' than the replacement
> which is just a cooling fan...

I would definitely suspect the pulsing rather than one 0.01A difference...

I'm sure there are several different constructs for the pulse signal...

	Johnny

>
> Cheers
>
> Adrian
>
> On 20 July 2015 at 16:17, Jon Elson <elson at pico-systems.com> wrote:
>
>> 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?
>>
>> Jon
>>
>
>
>


-- 
Johnny Billquist                  || "I'm on a bus
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