I'm powering my Z3815A from 48V, the telecom standard voltage.
On Wed, May 29, 2013 at 12:12 AM, Stewart Cobb <stewart.c...@gmail.com> wrote: > Your Z3815A may need more cooling than it's getting, especially if you have > it resting "horizontally" as it looks like it should. I bought one of > those "kits from China" about a year and a half ago. Powered it up, waited > for it to lock ... and it was dead within a week, with the unmistakable > smell of overheated electronics. One of the Vicor power bricks inside > (probably) overheated and shorted out. Here's what I learned: > > The Z3815A board was designed to go into a VXI-like mainframe, with a > carefully specified amount of cooling airflow. I think that particular > board was designed to require that airflow, and overheats without it. > There's a group in Australia which has experience with these boxes, and I > got the impression from my contacts with them that they see the Vicor > bricks fail pretty regularly. That would imply that they're not getting > the cooling they need, because Vicor bricks in other applications are > pretty reliable in my experience. > > You can see a photo of the original Z3815A on TVB's website here: > > <http://www.leapsecond.com/museum/z3815a/> > > The Z3815A I got from China was in a different case, just two bent pieces > of sheet aluminum. The case _looks_ official, with the right label on the > front and silkscreen on the back. But the board inside had a lot more crud > and corrosion than the nice clean case did, and parts of the plastic edge > connector on the back of the board were broken. Worst of all, the coaxial > cable from the antenna connector ended in a one-inch flying lead soldered > to the board. The "shield" of the coax cable ended in another flying lead, > soldered to ground somewhere else. (Any RF engineers reading this are > probably cringing now.) I'm pretty sure that no one at HP designed or > approved that connection. Once I saw it, I understood why the GPS receiver > appeared to be "deaf." Even connected to a very good antenna, it never saw > more than 4 satellites, and even those had weak signals. > > Did someone in China find a cache of bare Z3815 boards in a scrapyard > somewhere, and fab an official-looking case to match? I don't know, but it > might be the way to bet. Meanwhile, take the lid off your Z3815A and feel > the heatsinks on the power bricks. If they're too hot to touch, they're > too hot; give them some air. > > Cheers! > --Stu > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.