Hi Do you (or your assistant) have a cell phone? Where was it when the original issue occurred?
Yes, it’s a bit of a long shot, but I *have* seen test data messed up by the phone in a tech’s pocket. We finally worked it out when the speaker on the test computer started chirping as the cell phone did it’s “check into the mothership” thing. Bob > On Dec 17, 2016, at 1:56 PM, Pete Stephenson <[email protected]> wrote: > > On 12/15/2016 3:05 AM, Pete Stephenson wrote: >> Hi all, >> >> I have a Thunderbolt and am running Lady Heather 5. I've been seeing >> odd drops of ~0.7 degrees Celsius that slowly recover over around 10 >> minutes or so. This has happened 19 times in the last 36 hours. > > [snip] > > Hi all, > > I'm pleased -- but a little frustrated -- to report that I've been > unable to reproduce the issue after a few days of trying. A screenshot > of the happy Thunderbolt as shown by Lady Heather is attached. > > At first, I thought the issue might have been a dodgy USB-to-serial > dongle, so I connected the Tbolt directly to the computer's hardware > serial port (which normally is connected to another device). The issue > immediately cleared up. > > However, when I later reconnected the Tbolt to the same USB-to-serial > adapter (which uses a genuine FTDI chip) the problem did not recur. > > The power supply is a used, Cisco power supply provided by the Chinese > eBay vendor that sold me the Thunderbolt. My digital multimeter showed > that the voltages provided were, while not dead-on -12V, +12V, and +5V, > were within the specs required by the Thunderbolt's manual. > > Additionally, I probed the power pins with my oscilloscope both while > the Thunderbolt was powered off and also when I disconnected the power > connector. Visually, the traces appeared smooth, with no visible ripple > or spikes. The FFT function on the scope showed no spikes or anything > unusual between DC and 5 MHz (I didn't bother checking beyond that). > > Since the Thunderbolt had been turned off for a few months to save > electricity, I thought that perhaps the issue only occurred when the > unit was started after being cold. I unplugged it and let it cool > overnight, then started it again. Again, nothing unusual. It's working fine. > > The only other thing I can think that might have caused an issue is I > had recently connected another USB device (an Arduino Pro Micro > programmed as an EDtracker: http://www.edtracker.org.uk/) that had been > previously setup to use the same COM port number as the FTDI adapter. > Although Windows should prevent (or at least warn about) such conflicts, > it did not. It's possible that the output of the EDtracker was getting > mixed in with the serial data from the Thunderbolt and causing > corruption that Lady Heather interpreted as temperature and DAC excursions. > > Unfortunately, I can't seem to replicate the issue, so I'm out of ideas. > > In short: everything I can think to check seems to be ok. > > Thanks to all for the help and suggestions, but I think this issue is > resolved for the time being. > > Cheers! > -Pete > <screenshot.png>_______________________________________________ > 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.
