[time-nuts] Replacement fan in SR620

Magnus Danielson magnus at rubidium.dyndns.org
Sun Feb 2 16:07:31 EST 2014


On 02/02/14 21:34, Charles Steinmetz wrote:
> Magnus wrote:
>
>> These days I would assume that heat-pipes would be used to move heat
>> to a large external heat-sink. It's fairly cheap these days.
>
> I have looked into heat pipes for several projects, and in the end have
> never used them.  The main problem is that almost every solution is
> customized.  No trouble if you make PC motherboards or consumer-grade
> stereo amplifiers 50,000 at a time.  But most instruments are made in
> quantities of 5,000 or fewer, and it takes many years to make (sell)
> even that number.  With production numbers that low, the bean counters
> want the design and tooling costs amortized over the first year's
> production -- maybe only 100-500 units -- which can raise the retail
> price by a factor of 2-10.  At least that's what I've found.
>
> Also, most heat-pipe systems are gravity-fed, so if someone turns your
> product on its side they can burn it down.  (I almost always operate my
> "portable" spectrum analyzer (HP8591E) standing on its rear feet with
> the screen pointing up.  I can foresee someone with limited bench space
> setting an SR620 on its side.)

Good point.
The SR620 doesn't "stand" on the back very well, maybe on it's side, but 
that helps to close the little air intake there is...

Decided to finally toss the original box for my SIA-3000. It's just big 
and messy. Not tossing the SIA-3000 itself, it's a keeper.

Cheers,
Magnus




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