[time-nuts] Z3805A cooling requirements?

SAIDJACK at aol.com SAIDJACK at aol.com
Wed Dec 12 01:20:10 UTC 2012

a fan is about the worst thing you can do for your Z3805 it will  
significantly worsen the stability of the output frequency. The oven inside does  get 
warm, that's why it is an oven :)
The power consumption will go down once it heats itself up, the unit is  
designed to work without a fan sitting on a desk etc. Just make sure the vent  
holes are not clogged.
Sounds like your Z3816 had a failure that caused the units power  supply to 
In a message dated 12/11/2012 16:22:10 Pacific Standard Time,  
stewart.cobb at gmail.com writes:

This may  be a newbie question, but I'm a newbie, so:

Do the HP telecom GPSDOs  (Z38xx) require external airflow for cooling?
They don't have built-in  fans, but they sorta look like they depend on a
rack-level cooling fan,  which a telecom rack would almost certainly have.

I ask because I  bought a Z3816 awhile back which worked for about a week
and then failed. I  traced the failure to an internal power supply brick,
which had a big  finned heat-sink attached but nevertheless smelled
overheated and was  shorted internally.

I never found a replacement power brick, and I  don't have time to mess with
it right now, so I recently bought a Z3805A.  It, too, looks like it's
working, but it started to feel awfully warm after  a few hours, so I
unplugged it for now.

It probably wouldn't take  much of a fan to bring the internal temperature
down close to ambient, and  the fan could be powered easily enough from the
supply rails. But that  might create a temperature gradient where the
designers didn't intend one.  Or it might cause problems I don't even know
about yet.

At the  moment, the Z3805A is in a fan-less 19-inch rack with a bunch of
other  equipment, in a lab environment. Should it have its own  fan?


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