Wednesday, 11 May 2016

Dell 2950 Server - Fan Modification - Part 1

This is the first in a series I'm putting together, not to tutor, but to chronicle my altering the Dell 2950 servers I've just received to quieten them down.

The fans can be seen with the orange plastic handles.

I negotiated for the servers from a recycling shop, and got two for £80.  When the first two arrived, I was very happy with the look of them, one is 6 x 3.5" bays, one has 9 x 2.5" bays, but other than that they look in really good shape.

Inside they're clean, not perfect, but good.  Unfortunately someone not in the know has "set them up for shipping", so I have a bent front cheek on one unit, and then the memory in both is wrong, one has a single stick of 2GB RAM... and the other has 3 sticks of 512MB... First off, the servers ONLY take matched pairs, they complain without at least a matched pair... So from these sticks I can only manage to get 1GB as 2x512MB installed at the moment.

And then the big problem, was that one of the machines only has a single CPU installed, I only selected these as they were to come with two quad core CPU's...

But the vendor very kindly sent a replacement machine, unfortunately this machine has been dropped, so the rear of the case is very mangled.  But, never mind, that third machine is going to become a donor for spare parts on the other two!

So, what is the fan mod?  Well, I've read three different tutorials, taken a look at my unit, and watches lots of videos on the topic of quietening Dell server fans in general, but the 2950 specifically.

It is a two stage mod, the first is hardware, to fit a resistor to the red (power) cable on the four main input fans within the case.  This makes them run more slowly, and hence more quietly.

The problem with this is that the RPM meter then records a far lower rate, and so the system monitor/BIOS starts to complain that it has a defective fan, or four!...

This leads to the second stage of the modification, which is to modify the BIOS to stop this, by lowering the internally stored alert rates.

To prepare for the first step I removed my fans, and set about soldering the new resistors into place, I've started out with 47ohm 0.5W resistors, which are pretty high, some people have said they've had issues with fitting such a high resistance, in that the fan got way too slow.  So I have both 27 and 39 ohm resistors winging their way to me.

Once all four fans were soldered, I wrapped the fixes in insulation tape (I have no shrink wrap)... Refitting them of course left them running a lot slower, but the machine was not happy.

Therefore I'll move onto the next step, which is to fix the BIOS... See you all soon, to report how I get along.
Original Hand Wand Style Iron, which exploded

Oh, and during this step, I had the rubbish £10 soldering iron I was using explode (again), so I've gone and splashed out on a £50 digital one from Maplin, look out for a review of that soon!  (It soldered pretty well for a novice/hobbyist like me!)
Nice new Solder Station

Checking the work for continuity and then wrapping insulation.

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