The Z3815A here has (right now) 3.4us/24h of holdover uncertainty and -7.0ns PPS relative to GPS. The health monitor and the self test show OK everywhere. It is ON since 12, 2011.
On Wed, May 29, 2013 at 1:03 PM, Bob Camp <li...@rtty.us> wrote: > Hi > > Well, probably as good as the manual … we have the guy who designed it (Rick > Karlquist) lurking around here somewhere. I don't think I've ever seen a > manual. > > How long have you had the 3815? If not so long, I'd contact the seller. You > have indeed convinced me to quickly fire up the next one I have coming in. > > Bob > > > On May 29, 2013, at 2:14 AM, Mark C. Stephens <ma...@non-stop.com.au> wrote: > >> Wow the 2 black heatsinks on the puck are really hot - too hot to touch. >> I don't think that would be normal deign. >> They are probably the excessive current sink culprits. >> Anyone got a manual for the e1398a OCXO? >> >> >> -marki >> >> -----Original Message----- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >> Behalf Of Mark C. Stephens >> Sent: Wednesday, 29 May 2013 12:36 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Z3815A >> >> I believe these were all rescued from the Tip (Dump, Trash) judging by the >> water damage and bent cases. >> >> Mine had been tested in Japan and had approximate co-ordinates in it: >> https://www.google.com/search?q=34+44'+N+135+21'+E&oq=34+44'+N+135+21'+E >> >> Initially I had a OCXO communication error which I fixed by a :syst:pres >> (shrug, I thought it was pretty major at the time, I can tell you!) >> >> At the moment it's in an air scrubbed and temperature controlled room, >> naked, without its case. >> Both heatsinks are just slightly warm to the touch. >> However the Puck is fairly warm.. >> >> I still have "Holdover Uncertainty Predict: --" which is a bit of a worry. >> >> Also the 1PPS TI is always about -100ns relative to GPS, which is way out >> there.. >> >> >> -marki >> >> >> >> >> -----Original Message----- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >> Behalf Of Stewart Cobb >> Sent: Wednesday, 29 May 2013 8:13 AM >> To: time-nuts@febo.com >> Subject: Re: [time-nuts] Z3815A >> >> 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. >> >> >> _______________________________________________ >> 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. _______________________________________________ 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.
