[time-nuts] Replacement fan in SR620

[Magnus Danielson]

Charles,

On 02/02/14 21:06, Charles Steinmetz wrote:
> Magnus wrote:
>
>> I agree. You need both, but just tossing in a stronger fan isn't going
>> to cut it either.
>
> Very true.  You need to attack all of the problems to fix it.

Well, maybe not all of them, but there is several key areas that 
together form the basic problem.

We also have ECL dispersed throughout the right side of the board which 
also needs cooling. Most of that can be handled through general cooling 
if only air flows there.

I just checked the lab, and the SR620 standing on the somewhat crowded 
bench and with a SR620 manual laying on top of it was cooler than the 
SR620 sitting up among the other instruments.

As I re-checked the slots for air inlet I was amazed how little there where.

Letting more air in on the back would work if there is large enough air 
at the back, then setting a central baffle so that it at least sweeps 
over the electronics up to the front before being sucked over the CPU 
into the fan.

Also, the fan-noise did not change a lot by drying to damp the top lid, 
so it seems the fan emits it mostly as a direct mode.

The older unit has a high hiss to its fan while the newer has a more 
rattling sound to it.

Cheers,
Magnus