[time-nuts] Z3805A cooling requirements?

[Stewart Cobb]

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?

Cheers!
--Stu