Silencing a 3com 3300

I have a 3com 3300 switch at home, very nice to have for VLANs and enough
ports.

But for home use it has one disadvantage. Noise. It is geared towards
being used in cramped cabling spaces where it needs to blow a lot of air
to get itself cool.

In a home, that is too much noise.

First step: finding instructions how to open it.
(Thanks to Neil Hoggarth)

- Remove rack mount flanges
- Invert the case
- Remove 4 torex bolts from the underside
- Open plastic tabs (careful) and lift system from case

Second step: finding the fans

It has 2 Papst 612 NG fans on the inside (12V, 200mA). Size: 60x60x25 mm.

And a generally nice and clean design on the inside too.

Papst has a really nice website with catalogs (pdf format)
of their products. So I downloaded the catalog.

It denies the 612 NG fan. It does show several other 612-fans (all
60x60x25 mm and 12 volt supply). The most interesting in this row
is the fan with built-in automatic speed control by temperature,
either the 612 NGMI (sleeve bearing) or the 612 NMI (ball bearing).

Update: bought a new 612 NGN fan. It now uses only one fan (is
enough, given the temperature of the outgoing air). The main cause
of the noise seems to be the way the fan is seated in the housing,
which leaves a lot of room for resonance.