[time-nuts] Fan for old HP synthesizer

Didier Juges didier at cox.net
Tue Apr 18 20:22:23 EDT 2006

I have 3 HP synthesizers with what looks like the same fan: 8672, 8673 
and 8656, and they are all very loud, the worse being the 8656. On top 
of that, the 8656 fan still runs when the unit is in standby. I have 
thought many times that I wanted to replace it with a 12V model so that 
I could wire it to the switched 12V inside the unit so that it would run 
only when the unit is operating and not in standby, but that particular 
synthesizer draws a lot of power in standby, and I am affraid that it 
really needs cooling even then... So, for now, I turn it off completely 
between uses and until I have my GPS locked frequency reference, I sync 
it to the timebase in the 8673 when I need to.

I just got a 5 MHz ovenized crystal stabilized reference off eBay today, 
and I have a Jupiter receiver, so I am just some soldering away from a 
good frequency standard...

Didier KO4BB

Magnus Danielson wrote:

>When checking the EBM-Papst site (http://www.ebmpapst.us) the 92x92x25 mm fans did not
>reach the same CFM, but those that I found (3212JN and 3214JN) was not doing 117 VAC
>(they where doing 12 VDC and 24 VDC respectively). While Papst isn't all there is to fans
>they are usually a good benchmark on what is available.
>Come to think of it... I have a bunch of big nice Papst 9950 lying around ;O)
>A little bigger (119x119) and eating 230 VAC but good for CFM 68,9 so almost fit. ;O)

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