Re: [time-nuts] repairing General Technology (Tracor) 304-B rubidium standard
On 2/19/2013 12:54 PM, Magnus Danielson wrote: On 19/02/13 19:36, Ed Palmer wrote: Hi Stu, Did you find the long message threads from April May of last year where I was trying to fix my 304-B? Look for Antique Rubidium Standard, General Technology Corp model 304b and Antique Rb Standard. Lots of good info from guys like Magnus Danielson, Paul Swed, Ed Breya and others. To cut to the chase, no I haven't got it working. The second harmonic is still missing. I haven't given up. I still have a few puzzles to work out. I work on it for awhile, decide I need more equipment, wait for it to show up on the auction site, wait for it to be delivered, fix it and/or learn about it, make some measurements, get frustrated and walk away for awhile, repeat until wallet is empty and workshop is full. :-) Answers to your current questions are interspersed below. We'll talk more, but it's probably best if we take it offlist. I'll contact you directly. On 2/19/2013 12:36 AM, Stewart Cobb wrote: Guys, I'm repairing a 1960's vintage lab-grade rubidium standard, General Technology Corporation model 304-B. Apparently Tracor bought GTC soon after this unit was made, because references to this as a Tracor 304-B seem to be more common. I've made some progress, but now it seems like time to consult the hive mind. The unit appears clean, but it doesn't lock. I've read through old comments on the list regarding this unit, and I've downloaded a copy of the manual and schematics available at *http://sundry.i2phd.com/ServiceManual_304b.pdf* That file seems to contain a complete copy of the manual text, but some schematics are missing. In particular, the schematics for the sweep/acquisition board (A8) and the three boards inside the physics package (the lamp oscillator (A13), the SRD driver (A12), and the photocell preamp (A11)) are not shown. Does anyone know where to find copies of those schematics? I have a hard copy of the manual. I'll scan those schematics and send them to you. Could you put them on a suitable server? I don't know what server would be suitable. It's not like there are hordes of people who are desperately waiting to get their hands on this manual. Any suggestions? A frequency counter (GPSDO reference) shows that the crystal oven warms up as expected. The output can be centered on 5 MHz and the sweep circuit covers a symmetrical range around 5 MHz as expected. Really? That surprises me. Drift in the OCXO should have caused an issue over this much time. On my unit, some kind soul adjusted the oscillator via the adjustment on the oscillator itself. Unfortunately, that changes the oven temperature which does change the frequency, but it also moves the oscillator away from the crystal's turnover point. It still works, but for proper operation, the oscillator has to be opened and components changed to bring the oscillator back to it's proper frequency at the proper temperature. The ovens for the lamp and filter cell appear to warm up properly as well, judging from test points available on the A1 oven controller board. The test point voltages don't quite match the ones in the PDF manual, but it looks like those readings were typed into each individual manual after being read off the particular unit that came with that manual. That's one of the remaining puzzles on my unit. It appears that one of the thermistors on my unit has drifted badly and the RF cavity (and therefore the resonance cell) are running about 20C colder than they should. My next round of testing will investigate that. That would indeed help to keep the Rb-85 and Rb-87 peaks misaligned, with weak return signal as result. I tested the temperature early in my investigations. Raising or lowering the temperature reduced the maximum amplitude of the error signal so I left it alone. But the current temperature of 56C seemed suspiciously low. The correct temperature isn't stated in the manual. I was finally able to find the data for the thermistor and the current hot resistance should correlate to a temperature of ~72C which seems much more reasonable. So I'm going to boost the temperature to that level and then go hunting for a signal. The test point on the A5 board shows that 155 Hz resonance detector modulation is within spec. The A6 filter-amplifier board test points show the system attempting (and failing) to detect 155 Hz and 310 Hz resonance signals coming back from the photocell. The manual says that the A7 RF pre-driver board (the x14 multiplier) should be supplying 70 MHz at +13 dBm to the SRD driver inside the physics package. That would be about 2.8Vpp, assuming a 50-ohm system. Instead, it's supplying a clean 70 MHz at about 100mV into a 50-ohm load. My best guess is that the final amplifier transistor on that board is blown, possibly from being operated with only a scope probe as a load (infinite VSWR). Replacement transistors are on order. Any other thoughts? I've measured my A7
Re: [time-nuts] repairing General Technology (Tracor) 304-B rubidium standard
Could you put [scans of the manual] on a suitable server? I don't know what server would be suitable. * * * Any suggestions? http://www.ko4bb.com/Manuals/01%29_Upload_Instructions.php Best regards, Charles ___ 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.
Re: [time-nuts] repairing General Technology (Tracor) 304-B rubidium standard
On 19/02/13 07:36, Stewart Cobb wrote: Guys, I'm repairing a 1960's vintage lab-grade rubidium standard, General Technology Corporation model 304-B. Apparently Tracor bought GTC soon after this unit was made, because references to this as a Tracor 304-B seem to be more common. I've made some progress, but now it seems like time to consult the hive mind. The unit appears clean, but it doesn't lock. I've read through old comments on the list regarding this unit, and I've downloaded a copy of the manual and schematics available at *http://sundry.i2phd.com/ServiceManual_304b.pdf* That file seems to contain a complete copy of the manual text, but some schematics are missing. In particular, the schematics for the sweep/acquisition board (A8) and the three boards inside the physics package (the lamp oscillator (A13), the SRD driver (A12), and the photocell preamp (A11)) are not shown. Does anyone know where to find copies of those schematics? The main power supply voltage on my unit seems to have been deliberately adjusted lower than spec (18.54 V actual, versus 20 +/- 0.1V specified in the manual). Replacing a resistor on the regulator board (that had smoked from overload due to the low voltage) didn't change the voltage much. I had to crank the trimmer across half of its range to get the voltage back within spec. Nothing in the regulator circuitry seemed to have drifted enough to change the setpoint that much. Is there a reason why a tech would have deliberately set this voltage lower than spec, or did it just drift down over the years? A frequency counter (GPSDO reference) shows that the crystal oven warms up as expected. The output can be centered on 5 MHz and the sweep circuit covers a symmetrical range around 5 MHz as expected. The ovens for the lamp and filter cell appear to warm up properly as well, judging from test points available on the A1 oven controller board. The test point voltages don't quite match the ones in the PDF manual, but it looks like those readings were typed into each individual manual after being read off the particular unit that came with that manual. The test point on the A5 board shows that 155 Hz resonance detector modulation is within spec. The A6 filter-amplifier board test points show the system attempting (and failing) to detect 155 Hz and 310 Hz resonance signals coming back from the photocell. The manual says that the A7 RF pre-driver board (the x14 multiplier) should be supplying 70 MHz at +13 dBm to the SRD driver inside the physics package. That would be about 2.8Vpp, assuming a 50-ohm system. Instead, it's supplying a clean 70 MHz at about 100mV into a 50-ohm load. My best guess is that the final amplifier transistor on that board is blown, possibly from being operated with only a scope probe as a load (infinite VSWR). Replacement transistors are on order. Any other thoughts? Trimming might have drifted. OK signal in? On a HP5060 (similar vintage) I had to start by tuning the crystal filter of the OCXO to get a strong 5 MHz. I ended up having trouble with the multiplier board. Obviously, the box won't lock until the RF input is the right level. But it also requires the Rb lamp to light. Corby Dawson posted to the list back on 12 November 2009: Tracor bulbs fail with a different mechanism and last maybe 10 years. Anyone know what that different failure mechanism is? Is it repairable in an ordinary lab, like the heat-gun trick for LPRO bulbs? If not, is it feasible to build a Frankenstein replacement using something like an LPRO or FEI bulb? Is it possible to tell whether the lamp is lit without opening the physics package? If not, are there any tricks to opening the physics package? Any precautions to take before doing so? The photodetector should detect the lamp intensity as a DC component. The modulation doesn't cut out much of the light, so the 155 Hz and 310 Hz is there only when things are properly aligned. The tricky part is that not only the frequency needs to be aligned, but also the temperature of the lamp with the temperature of the filter and resonance cell. Check the oven settings on it. The temperature alignment is needed to make the optical pumping align up and work well, if you don't too little pumping is achieved, and too few atomis is in the right state to later alter state with your applied signal and hence gives a much weaker signal. Any other comments on how to get this box working again? Check the return signal yourself. It could be that you have the 155 Hz and 310 Hz, but you need to re-align the phase of the synchronous detector, but this only comes after getting the 70 MHz operating again. Cheers! --Stu Side note: This unit was built during the era of elastic seconds (roughly, the 1960's). It contains a board (A9) which digitally offsets the output frequency in increments of roughly 7E-10, without changing the rubidium resonance frequency or the C-field. There's also a note in
Re: [time-nuts] repairing General Technology (Tracor) 304-B rubidium standard
Hi Keep in mind that the Tracor's came out before the Teflon coated bulbs. Without the Teflon, the Rb will combine with the glass of the bulb. The ones I have seen slowly turn a black. As they darken, the light transmission drops enough to stop the standard. Since it's a chemical reaction, there is no simple way to reverse it. Bob On Feb 19, 2013, at 1:36 AM, Stewart Cobb stewart.c...@gmail.com wrote: Guys, I'm repairing a 1960's vintage lab-grade rubidium standard, General Technology Corporation model 304-B. Apparently Tracor bought GTC soon after this unit was made, because references to this as a Tracor 304-B seem to be more common. I've made some progress, but now it seems like time to consult the hive mind. The unit appears clean, but it doesn't lock. I've read through old comments on the list regarding this unit, and I've downloaded a copy of the manual and schematics available at *http://sundry.i2phd.com/ServiceManual_304b.pdf* That file seems to contain a complete copy of the manual text, but some schematics are missing. In particular, the schematics for the sweep/acquisition board (A8) and the three boards inside the physics package (the lamp oscillator (A13), the SRD driver (A12), and the photocell preamp (A11)) are not shown. Does anyone know where to find copies of those schematics? The main power supply voltage on my unit seems to have been deliberately adjusted lower than spec (18.54 V actual, versus 20 +/- 0.1V specified in the manual). Replacing a resistor on the regulator board (that had smoked from overload due to the low voltage) didn't change the voltage much. I had to crank the trimmer across half of its range to get the voltage back within spec. Nothing in the regulator circuitry seemed to have drifted enough to change the setpoint that much. Is there a reason why a tech would have deliberately set this voltage lower than spec, or did it just drift down over the years? A frequency counter (GPSDO reference) shows that the crystal oven warms up as expected. The output can be centered on 5 MHz and the sweep circuit covers a symmetrical range around 5 MHz as expected. The ovens for the lamp and filter cell appear to warm up properly as well, judging from test points available on the A1 oven controller board. The test point voltages don't quite match the ones in the PDF manual, but it looks like those readings were typed into each individual manual after being read off the particular unit that came with that manual. The test point on the A5 board shows that 155 Hz resonance detector modulation is within spec. The A6 filter-amplifier board test points show the system attempting (and failing) to detect 155 Hz and 310 Hz resonance signals coming back from the photocell. The manual says that the A7 RF pre-driver board (the x14 multiplier) should be supplying 70 MHz at +13 dBm to the SRD driver inside the physics package. That would be about 2.8Vpp, assuming a 50-ohm system. Instead, it's supplying a clean 70 MHz at about 100mV into a 50-ohm load. My best guess is that the final amplifier transistor on that board is blown, possibly from being operated with only a scope probe as a load (infinite VSWR). Replacement transistors are on order. Any other thoughts? Obviously, the box won't lock until the RF input is the right level. But it also requires the Rb lamp to light. Corby Dawson posted to the list back on 12 November 2009: Tracor bulbs fail with a different mechanism and last maybe 10 years. Anyone know what that different failure mechanism is? Is it repairable in an ordinary lab, like the heat-gun trick for LPRO bulbs? If not, is it feasible to build a Frankenstein replacement using something like an LPRO or FEI bulb? Is it possible to tell whether the lamp is lit without opening the physics package? If not, are there any tricks to opening the physics package? Any precautions to take before doing so? Any other comments on how to get this box working again? Cheers! --Stu Side note: This unit was built during the era of elastic seconds (roughly, the 1960's). It contains a board (A9) which digitally offsets the output frequency in increments of roughly 7E-10, without changing the rubidium resonance frequency or the C-field. There's also a note in the manual saying that annual changes to the definition of the second may require replacing the rubidium resonance cell in the physics package with a new cell calibrated for the new second in the new year. Leap seconds bring their own problems, but compared to dismantling your lab instruments every year, they're a breeze. ___ 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] repairing General Technology (Tracor) 304-B rubidium standard
Stewart, Tracor units use a high voltage pulse to start the lamp. You should be able to hear the relay that drives the pulse clicking around every 10 seconds or so until the lamp lights up. Tracor lamp failures are not rejuvinatable (is that really a word). However I have in the past installed Efratom lamps into some 304D units. Corby ___ 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.
Re: [time-nuts] repairing General Technology (Tracor) 304-B rubidium standard
Hi Stu, Did you find the long message threads from April May of last year where I was trying to fix my 304-B? Look for Antique Rubidium Standard, General Technology Corp model 304b and Antique Rb Standard. Lots of good info from guys like Magnus Danielson, Paul Swed, Ed Breya and others. To cut to the chase, no I haven't got it working. The second harmonic is still missing. I haven't given up. I still have a few puzzles to work out. I work on it for awhile, decide I need more equipment, wait for it to show up on the auction site, wait for it to be delivered, fix it and/or learn about it, make some measurements, get frustrated and walk away for awhile, repeat until wallet is empty and workshop is full. :-) Answers to your current questions are interspersed below. We'll talk more, but it's probably best if we take it offlist. I'll contact you directly. On 2/19/2013 12:36 AM, Stewart Cobb wrote: Guys, I'm repairing a 1960's vintage lab-grade rubidium standard, General Technology Corporation model 304-B. Apparently Tracor bought GTC soon after this unit was made, because references to this as a Tracor 304-B seem to be more common. I've made some progress, but now it seems like time to consult the hive mind. The unit appears clean, but it doesn't lock. I've read through old comments on the list regarding this unit, and I've downloaded a copy of the manual and schematics available at *http://sundry.i2phd.com/ServiceManual_304b.pdf* That file seems to contain a complete copy of the manual text, but some schematics are missing. In particular, the schematics for the sweep/acquisition board (A8) and the three boards inside the physics package (the lamp oscillator (A13), the SRD driver (A12), and the photocell preamp (A11)) are not shown. Does anyone know where to find copies of those schematics? I have a hard copy of the manual. I'll scan those schematics and send them to you. The main power supply voltage on my unit seems to have been deliberately adjusted lower than spec (18.54 V actual, versus 20 +/- 0.1V specified in the manual). Replacing a resistor on the regulator board (that had smoked from overload due to the low voltage) didn't change the voltage much. I had to crank the trimmer across half of its range to get the voltage back within spec. Nothing in the regulator circuitry seemed to have drifted enough to change the setpoint that much. Is there a reason why a tech would have deliberately set this voltage lower than spec, or did it just drift down over the years? I can't think why the voltage would be intentionally adjusted down. Probably just drift. A frequency counter (GPSDO reference) shows that the crystal oven warms up as expected. The output can be centered on 5 MHz and the sweep circuit covers a symmetrical range around 5 MHz as expected. Really? That surprises me. Drift in the OCXO should have caused an issue over this much time. On my unit, some kind soul adjusted the oscillator via the adjustment on the oscillator itself. Unfortunately, that changes the oven temperature which does change the frequency, but it also moves the oscillator away from the crystal's turnover point. It still works, but for proper operation, the oscillator has to be opened and components changed to bring the oscillator back to it's proper frequency at the proper temperature. The ovens for the lamp and filter cell appear to warm up properly as well, judging from test points available on the A1 oven controller board. The test point voltages don't quite match the ones in the PDF manual, but it looks like those readings were typed into each individual manual after being read off the particular unit that came with that manual. That's one of the remaining puzzles on my unit. It appears that one of the thermistors on my unit has drifted badly and the RF cavity (and therefore the resonance cell) are running about 20C colder than they should. My next round of testing will investigate that. The test point on the A5 board shows that 155 Hz resonance detector modulation is within spec. The A6 filter-amplifier board test points show the system attempting (and failing) to detect 155 Hz and 310 Hz resonance signals coming back from the photocell. The manual says that the A7 RF pre-driver board (the x14 multiplier) should be supplying 70 MHz at +13 dBm to the SRD driver inside the physics package. That would be about 2.8Vpp, assuming a 50-ohm system. Instead, it's supplying a clean 70 MHz at about 100mV into a 50-ohm load. My best guess is that the final amplifier transistor on that board is blown, possibly from being operated with only a scope probe as a load (infinite VSWR). Replacement transistors are on order. Any other thoughts? I've measured my A7 output at +12 dBm. I've also found that the level isn't critical. Levels as low as +5 dBm didn't reduce the amplitude of the error signal. Obviously, the box won't lock until the RF input
Re: [time-nuts] repairing General Technology (Tracor) 304-B rubidium standard
On 19/02/13 19:36, Ed Palmer wrote: Hi Stu, Did you find the long message threads from April May of last year where I was trying to fix my 304-B? Look for Antique Rubidium Standard, General Technology Corp model 304b and Antique Rb Standard. Lots of good info from guys like Magnus Danielson, Paul Swed, Ed Breya and others. To cut to the chase, no I haven't got it working. The second harmonic is still missing. I haven't given up. I still have a few puzzles to work out. I work on it for awhile, decide I need more equipment, wait for it to show up on the auction site, wait for it to be delivered, fix it and/or learn about it, make some measurements, get frustrated and walk away for awhile, repeat until wallet is empty and workshop is full. :-) Answers to your current questions are interspersed below. We'll talk more, but it's probably best if we take it offlist. I'll contact you directly. On 2/19/2013 12:36 AM, Stewart Cobb wrote: Guys, I'm repairing a 1960's vintage lab-grade rubidium standard, General Technology Corporation model 304-B. Apparently Tracor bought GTC soon after this unit was made, because references to this as a Tracor 304-B seem to be more common. I've made some progress, but now it seems like time to consult the hive mind. The unit appears clean, but it doesn't lock. I've read through old comments on the list regarding this unit, and I've downloaded a copy of the manual and schematics available at *http://sundry.i2phd.com/ServiceManual_304b.pdf* That file seems to contain a complete copy of the manual text, but some schematics are missing. In particular, the schematics for the sweep/acquisition board (A8) and the three boards inside the physics package (the lamp oscillator (A13), the SRD driver (A12), and the photocell preamp (A11)) are not shown. Does anyone know where to find copies of those schematics? I have a hard copy of the manual. I'll scan those schematics and send them to you. Could you put them on a suitable server? A frequency counter (GPSDO reference) shows that the crystal oven warms up as expected. The output can be centered on 5 MHz and the sweep circuit covers a symmetrical range around 5 MHz as expected. Really? That surprises me. Drift in the OCXO should have caused an issue over this much time. On my unit, some kind soul adjusted the oscillator via the adjustment on the oscillator itself. Unfortunately, that changes the oven temperature which does change the frequency, but it also moves the oscillator away from the crystal's turnover point. It still works, but for proper operation, the oscillator has to be opened and components changed to bring the oscillator back to it's proper frequency at the proper temperature. The ovens for the lamp and filter cell appear to warm up properly as well, judging from test points available on the A1 oven controller board. The test point voltages don't quite match the ones in the PDF manual, but it looks like those readings were typed into each individual manual after being read off the particular unit that came with that manual. That's one of the remaining puzzles on my unit. It appears that one of the thermistors on my unit has drifted badly and the RF cavity (and therefore the resonance cell) are running about 20C colder than they should. My next round of testing will investigate that. That would indeed help to keep the Rb-85 and Rb-87 peaks misaligned, with weak return signal as result. The test point on the A5 board shows that 155 Hz resonance detector modulation is within spec. The A6 filter-amplifier board test points show the system attempting (and failing) to detect 155 Hz and 310 Hz resonance signals coming back from the photocell. The manual says that the A7 RF pre-driver board (the x14 multiplier) should be supplying 70 MHz at +13 dBm to the SRD driver inside the physics package. That would be about 2.8Vpp, assuming a 50-ohm system. Instead, it's supplying a clean 70 MHz at about 100mV into a 50-ohm load. My best guess is that the final amplifier transistor on that board is blown, possibly from being operated with only a scope probe as a load (infinite VSWR). Replacement transistors are on order. Any other thoughts? I've measured my A7 output at +12 dBm. I've also found that the level isn't critical. Levels as low as +5 dBm didn't reduce the amplitude of the error signal. Once sufficient, levels should be set somewhat below peaking, and preferably for best stability. Signal level shift causes frequency shift. It's a bit obscure actually. Anyway, if you can have a servo-loop to maintain a stable level over time, it will reduce the drift. Any other comments on how to get this box working again? Invest copious amounts of time, money, and frustration. Odds of success are unknown, but probably not great. The effort will either keep you out of the bar or drive you to it. But you will learn lots about how a Rb standard works! ;-) Indeed. You guys are lucky, on one of my rubidiums I have a
[time-nuts] repairing General Technology (Tracor) 304-B rubidium standard
Guys, I'm repairing a 1960's vintage lab-grade rubidium standard, General Technology Corporation model 304-B. Apparently Tracor bought GTC soon after this unit was made, because references to this as a Tracor 304-B seem to be more common. I've made some progress, but now it seems like time to consult the hive mind. The unit appears clean, but it doesn't lock. I've read through old comments on the list regarding this unit, and I've downloaded a copy of the manual and schematics available at *http://sundry.i2phd.com/ServiceManual_304b.pdf* That file seems to contain a complete copy of the manual text, but some schematics are missing. In particular, the schematics for the sweep/acquisition board (A8) and the three boards inside the physics package (the lamp oscillator (A13), the SRD driver (A12), and the photocell preamp (A11)) are not shown. Does anyone know where to find copies of those schematics? The main power supply voltage on my unit seems to have been deliberately adjusted lower than spec (18.54 V actual, versus 20 +/- 0.1V specified in the manual). Replacing a resistor on the regulator board (that had smoked from overload due to the low voltage) didn't change the voltage much. I had to crank the trimmer across half of its range to get the voltage back within spec. Nothing in the regulator circuitry seemed to have drifted enough to change the setpoint that much. Is there a reason why a tech would have deliberately set this voltage lower than spec, or did it just drift down over the years? A frequency counter (GPSDO reference) shows that the crystal oven warms up as expected. The output can be centered on 5 MHz and the sweep circuit covers a symmetrical range around 5 MHz as expected. The ovens for the lamp and filter cell appear to warm up properly as well, judging from test points available on the A1 oven controller board. The test point voltages don't quite match the ones in the PDF manual, but it looks like those readings were typed into each individual manual after being read off the particular unit that came with that manual. The test point on the A5 board shows that 155 Hz resonance detector modulation is within spec. The A6 filter-amplifier board test points show the system attempting (and failing) to detect 155 Hz and 310 Hz resonance signals coming back from the photocell. The manual says that the A7 RF pre-driver board (the x14 multiplier) should be supplying 70 MHz at +13 dBm to the SRD driver inside the physics package. That would be about 2.8Vpp, assuming a 50-ohm system. Instead, it's supplying a clean 70 MHz at about 100mV into a 50-ohm load. My best guess is that the final amplifier transistor on that board is blown, possibly from being operated with only a scope probe as a load (infinite VSWR). Replacement transistors are on order. Any other thoughts? Obviously, the box won't lock until the RF input is the right level. But it also requires the Rb lamp to light. Corby Dawson posted to the list back on 12 November 2009: Tracor bulbs fail with a different mechanism and last maybe 10 years. Anyone know what that different failure mechanism is? Is it repairable in an ordinary lab, like the heat-gun trick for LPRO bulbs? If not, is it feasible to build a Frankenstein replacement using something like an LPRO or FEI bulb? Is it possible to tell whether the lamp is lit without opening the physics package? If not, are there any tricks to opening the physics package? Any precautions to take before doing so? Any other comments on how to get this box working again? Cheers! --Stu Side note: This unit was built during the era of elastic seconds (roughly, the 1960's). It contains a board (A9) which digitally offsets the output frequency in increments of roughly 7E-10, without changing the rubidium resonance frequency or the C-field. There's also a note in the manual saying that annual changes to the definition of the second may require replacing the rubidium resonance cell in the physics package with a new cell calibrated for the new second in the new year. Leap seconds bring their own problems, but compared to dismantling your lab instruments every year, they're a breeze. ___ 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.
