Wayne, are you sure your LPRO actually locks? You say you have measured 10.000 MHz but you don't mention the other decimals. Some years ago I characterized some LPROs of mine, and from my notebook I take that, on one sample for instance, prior to lock the frequency swept up and down between (about) 9.999860 and 10.000230. Such a span was rather typical among units. A faulty unit of mine remained stuck at the upper limit without reversing the sweep. This was due to a faulty resistor in one of the two (upper) voltage comparator circuits. Anyway I don't know if this would affect the BITE, but I suggest you to check the other decimals.
Antonio I8IOV > >The BITE signal is the only way to to know if it has a lock... > >Wayne > >> On Mar 22, 2016, at 4:37 AM, Bob Camp <[email protected]> wrote: >> >> Hi >> >> There are probably a dozen or more things that contribute to the BITE output. It could be >> a regulator out of range. It also could be the VCXO nearing tune limit. If the unit locks up and >> seems to work, I’d ignore it and move on. >> >> Bob >> >>> On Mar 21, 2016, at 9:42 PM, Wayne Holder <[email protected]> wrote: >>> >>> I have a surplus LPRO-101 that seems to power up OK. The power draw starts >>> at 1.7 Amps and then, after a few minutes, drops down to 600 mA, or so and, >>> after this startup, the output shows a 10.000 MHz signal thats 's >>> accurately as I can measure it. The lamp voltage is 6.2 volts, which seems >>> within spec. However, the BITE signal that's supposed to indicate lock >>> with a LOW level is always LOW and never changes. The docs say that BITE >>> signal should start at a HIGH level to indicate no lock and then drop to a >>> LOW when lock is obtained. So, this behavior seems all wrong. >>> >>> I opened the case and observed the purple glow of the lamp and probed >>> around IC U401, which buffers the BITE signal, and saw the same signal LOW >>> level. U401 is getting 5 volt power and the inputs to the AND gate used as >>> a buffer for the BITE signal match what I'd expect. But, lacking a proper >>> schematic, I'm not sure how to trace this back to the problem. Has anyone >>> ever seen a symptom like this with an LPRO101? >>> >>> Wayne _______________________________________________ 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.
