20 Jul
2015
20 Jul
'15
8:37 a.m.
On 2015-07-20 17:31, Adrian Graham wrote:
Hi,
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
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... 
Cheers
Adrian
On 20 July 2015 at 16:17, Jon Elson <elson at pico-systems.com> wrote:
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
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