[time-nuts] Replacement fan in SR620

[Volker Esper]

Magnus,

> Yes, and the EBM-Papst 624 matches it well. The Papst seems to have
> much lower noise from the datasheet.

There's yet another problem: the mechanical construction conducts the
fan noise to the case, so the noise is kind of amplified by the case. I
felt somewhat disappointed after replacing the fan, don't expect too much.

I just read the postings of Charles and I, too, was unhappy with the
startup behaviour. I changed the values of the driver circuit, but kept
the sensor in the tunnel. That helped making the motor speed rising
monotonically.

The air inlets are too small - that's true, if you need so much air
flow. We agree that the fan speed is at it's maximum, not at it's
equilibrium. So I tried to separate the heat sources. At the right (and
left) side of the case various voltage regulators heat the side wall. I
placed a heat sink with vertikal fins from the outside on that wall, the
screws of the regulators screwed into the aluminium. I'll  further place
a wall inside the counter right before those heating parts. The
experiment isn't completed yet, but I'm keen enough to claim that it'll
help to stabilize internal temperature particularly at the sensitive
components.

Volker