Hi Bob,
I jumped into pForth: p4th D > pr_adc_avg 12A: 11.86 5V: 4.99 12C: 12.14 -12A: -11.28 -12C: -11.31 -12E: -11.17 Oscillator current: 118.91 Antenna current: 17.04 So Power looks pretty average (yay!) But whats up with current drift = 0.0e+00 / day below? p4th D > pll_rep start ptr = 0 stop_ptr = 27 max loop time = 1000 ffom = 0 tfom = 1.0e-06 secs last efc average = 0.0 current drift = 0.0e+00 / day I wonder if that is why I have no Pred Unc? -marki -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bob Camp Sent: Wednesday, 29 May 2013 9:03 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Z3815A 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 <[email protected]> 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: [email protected] [mailto:[email protected]] > 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: [email protected] [mailto:[email protected]] > On Behalf Of Stewart Cobb > Sent: Wednesday, 29 May 2013 8:13 AM > To: [email protected] > 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 -- [email protected] To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
