Re: [time-nuts] Is a crystal likely to change frequency by 3% ?
On 13 Sep 2014 01:23, Alexander Pummer alex...@ieee.org wrote: just open the box, look for the wires which going to the magnet which drives the minute hand and measure the period time -- not the frequency, it is to low yes analog quarz clock slows down as the battery get old, you will be surprised, that the driver pulse's period time dos not change, but sometimes the divider chain or the mechanic skips a pulse, as the battery voltage drops further suddenly the clock mechanic or the electronic will stop working, takes less current so the battery recovers a bit, because the magnet did not used power for a while, and will run again for a while, the pause between two run time will be larger and larger so the clock looks like going slower 73 Alex So if it the mechanics skips a pulse, one really needs some method of measuring the position of the hands and recording that. In any case, the explanation you give is different to Dave McGuire. Maybe the second hand is more likely to slip if trying to fight gravity (between 30 and 0 seconds) and less likely when gravity helps (between 0 and 30 seconds) It would be interesting to see a detailed study of this. Dave ___ 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] Is a crystal likely to change frequency by 3% ?
On 13 Sep 2014 04:39, David McGaw n1...@dartmouth.edu wrote: The battery probably was going weak and the oscillator coming out of full control by the crystal. The tuning-fork crystal used in RTCs is not as high-Q as a MHz crystal. I have noticed clocks using these can go quite slow at low voltage. The crystal acts more like an inductor in this case and resonates with the increased junction capacitance at low voltage. David Two very different explanations from two different people about why clocks slow when the battery gets old. BTW Dave, please reply by my private email about whether you want the loads measured before I send them, given the VNA is at Keysight for calibration. Dave ___ 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] Is a crystal likely to change frequency by 3% ?
On Sat, Sep 13, 2014 at 8:08 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: So if it the mechanics skips a pulse, one really needs some method of measuring the position of the hands and recording that. Better modern quartz movements, have circuitry in the pulse driver that senses reluctance during the drive and will adjust the drive level down to save battery power if mechanical drag is low, and when the drag level is high (maybe fighting against gravity) even re-do the failed advances. The mechanical WWVB movements also have sensors for calibrating position of hour/minute/second hands (usually at a single fixed point on the dial). Tim. ___ 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] Is a crystal likely to change frequency by 3% ?
Hi In this era of “everything runs at GHz” it’s a bit tough to reach back to the sort of process used for watch IC’s. The idea is to optimize for low power / low leakage. They make enough of them that an application specific process can be used. The divide side of the chip may have an Fmax of 60 KHz at full battery voltage. By the time the battery gets to 1/2 voltage, the Fmax may have dropped to 30 KHz. The boundary is never an exact thing. It’s a “probability of working” kind of limit. Lots of possibilities. Bob On Sep 12, 2014, at 6:52 PM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: Dr David Kirkby Managing Director Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT, United Kingdom Registered in England and Wales as company number 08914892 http://www.kirkbymicrowave.co.uk/ Tel 07910 441670 / +44 7910 441670 (0900-2100 GMT) On 12 Sep 2014 12:18, Bob Camp kb...@n1k.org wrote: Hi Hi, If this is an RTC, it’s probably running off of a battery when the machine is powered down. It is far more likely that the oscillator is dropping out (stopping) rather than shifting frequency. Good point, I never thought of that. I have however noticed that analogue quartz clocks slow as the battery goes flat. But maybe too they stop and start. It would make an interesting experiment to check it, but one would need some method of logging the time from the hands. Conceptually that is not difficult, but it needs more work than I want to do. One could do it with a video camera and a fair bit of work writing the software. Probably easier is logging battery voltage and current as that should show if it starts and stops. ___ 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.
Re: [time-nuts] Is a crystal likely to change frequency by 3% ?
there is only one magnet, which drives the fastest moving arm -- the pointer for the seconds -- the other arms are connected via gears, by the way that case with the weak periodically recovering battery is an observed one, I connected a paper chart recorder to the clock and recorded the battery voltage change and the driver pulses of the magnet -- the recorder was not able to follow the individual pulses, but the envelope 73 Alex On 9/13/2014 5:08 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: On 13 Sep 2014 01:23, Alexander Pummer alex...@ieee.org wrote: just open the box, look for the wires which going to the magnet which drives the minute hand and measure the period time -- not the frequency, it is to low yes analog quarz clock slows down as the battery get old, you will be surprised, that the driver pulse's period time dos not change, but sometimes the divider chain or the mechanic skips a pulse, as the battery voltage drops further suddenly the clock mechanic or the electronic will stop working, takes less current so the battery recovers a bit, because the magnet did not used power for a while, and will run again for a while, the pause between two run time will be larger and larger so the clock looks like going slower 73 Alex So if it the mechanics skips a pulse, one really needs some method of measuring the position of the hands and recording that. In any case, the explanation you give is different to Dave McGuire. Maybe the second hand is more likely to slip if trying to fight gravity (between 30 and 0 seconds) and less likely when gravity helps (between 0 and 30 seconds) It would be interesting to see a detailed study of this. Dave ___ 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.
Re: [time-nuts] Is a crystal likely to change frequency by 3% ?
Interesting topic! Of course I no longer wear a watch since such a habit after advancing well into retirement seems pointless but I did want to point out that perhaps you could include the Bulova Accutron in your studies. Long ago I fell on ice and landed on my wrist with the result that my space model accutron never ran again . But a year ago I asked my wife where it was and she produced it which was then entrusted to a local horologist who studied it and said he couldn't get the parts to repair it. But after he had examined it I found that it did, indeed, start running again--for a time. But then it stopped and I gave up since others skilled in the art simply wanted more for a repair than I wanted to give. But I will still admit that from time to time a watch is a good thing and I find that the seven dollar models I can buy today keep time much better than the old Accutron ever did! Encouraging regards, Lee - Original Message - From: Alexander Pummer alex...@ieee.org To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 13, 2014 6:44 AM Subject: Re: [time-nuts] Is a crystal likely to change frequency by 3% ? there is only one magnet, which drives the fastest moving arm -- the pointer for the seconds -- the other arms are connected via gears, by the way that case with the weak periodically recovering battery is an observed one, I connected a paper chart recorder to the clock and recorded the battery voltage change and the driver pulses of the magnet -- the recorder was not able to follow the individual pulses, but the envelope 73 Alex ___ 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] Is a crystal likely to change frequency by 3% ?
On 12 Sep 2014 03:35, Alex Pummer a...@pcscons.com wrote: No that is to much, except if you overdrive it and you are so lucky that after it broke it is still working on a different frequency, but I would suggest check your frequency counter too, because 3% off of a clock frequency wold make the clock almost unusable not just for time nuts... 73 KJ5UHN This was a follow up post to something I wrote a year ago. I think you have misunderstood me. 1) The clock is in a commercial instrument - HP 8720D vector network analyzer. 2) When I got the instrument the internal clock which gives the date and time was loosing about a day per month, which is roughly 3% from a quick mental calculation. That was an unacceptable 3) Now it keeps within a few seconds per month. I have not bothered checking the actual frequency of the oscillator with a counter or logging the time reported by the clock on a regular basis, but it is now sufficiently accurate for my usage. I only use it to record the date and time I take a measurement with the network analyzer. Given a typical set of measurements takes a minute or so, worrying about the exact time is pointless. There must be at least 3 independent oscillators in this machine. 1) Real time clock. 2) 10 MHz standard oscillator. 3) Optional high stability 10 MHz oscillator. I don't know if that is an oven or not. I know last time it was calibrated by Agilent is was off about 0.25 Hz. When the VNA was calibrated by Agilent a year ago, the accuracy of the RTC was not checked. There is no published specification for it. The standard 10 MHz oscillator was within spec. I don't recall the error. The optional 10 MHz high stability oscillator was in error by about 0.25 Hz. The specification is +/- 1 Hz. I don't know if that is an oven or not. There's nothing to indicate the oven is cold, but given the specifications of the instrument are based on a one hour warmup period, maybe HP thought there was no point in indicating if the oven is cold. Or maybe there's no oven. Dave, G8WRB ___ 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] Is a crystal likely to change frequency by 3% ?
Hi If this is an RTC, it’s probably running off of a battery when the machine is powered down. It is far more likely that the oscillator is dropping out (stopping) rather than shifting frequency. One way it might do this is to stop for a relatively brief period, battery recovers, and then start back up again. Another way it might do this is to go into a squedge mode (audio speed blocking) at low voltage levels. Bob On Sep 12, 2014, at 4:09 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: On 12 Sep 2014 03:35, Alex Pummer a...@pcscons.com wrote: No that is to much, except if you overdrive it and you are so lucky that after it broke it is still working on a different frequency, but I would suggest check your frequency counter too, because 3% off of a clock frequency wold make the clock almost unusable not just for time nuts... 73 KJ5UHN This was a follow up post to something I wrote a year ago. I think you have misunderstood me. 1) The clock is in a commercial instrument - HP 8720D vector network analyzer. 2) When I got the instrument the internal clock which gives the date and time was loosing about a day per month, which is roughly 3% from a quick mental calculation. That was an unacceptable 3) Now it keeps within a few seconds per month. I have not bothered checking the actual frequency of the oscillator with a counter or logging the time reported by the clock on a regular basis, but it is now sufficiently accurate for my usage. I only use it to record the date and time I take a measurement with the network analyzer. Given a typical set of measurements takes a minute or so, worrying about the exact time is pointless. There must be at least 3 independent oscillators in this machine. 1) Real time clock. 2) 10 MHz standard oscillator. 3) Optional high stability 10 MHz oscillator. I don't know if that is an oven or not. I know last time it was calibrated by Agilent is was off about 0.25 Hz. When the VNA was calibrated by Agilent a year ago, the accuracy of the RTC was not checked. There is no published specification for it. The standard 10 MHz oscillator was within spec. I don't recall the error. The optional 10 MHz high stability oscillator was in error by about 0.25 Hz. The specification is +/- 1 Hz. I don't know if that is an oven or not. There's nothing to indicate the oven is cold, but given the specifications of the instrument are based on a one hour warmup period, maybe HP thought there was no point in indicating if the oven is cold. Or maybe there's no oven. Dave, G8WRB ___ 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.
Re: [time-nuts] Is a crystal likely to change frequency by 3% ?
Dr David Kirkby Managing Director Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT, United Kingdom Registered in England and Wales as company number 08914892 http://www.kirkbymicrowave.co.uk/ Tel 07910 441670 / +44 7910 441670 (0900-2100 GMT) On 12 Sep 2014 12:18, Bob Camp kb...@n1k.org wrote: Hi Hi, If this is an RTC, it’s probably running off of a battery when the machine is powered down. It is far more likely that the oscillator is dropping out (stopping) rather than shifting frequency. Good point, I never thought of that. I have however noticed that analogue quartz clocks slow as the battery goes flat. But maybe too they stop and start. It would make an interesting experiment to check it, but one would need some method of logging the time from the hands. Conceptually that is not difficult, but it needs more work than I want to do. One could do it with a video camera and a fair bit of work writing the software. Probably easier is logging battery voltage and current as that should show if it starts and stops. ___ 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] Is a crystal likely to change frequency by 3% ?
just open the box, look for the wires which going to the magnet which drives the minute hand and measure the period time -- not the frequency, it is to low yes analog quarz clock slows down as the battery get old, you will be surprised, that the driver pulse's period time dos not change, but sometimes the divider chain or the mechanic skips a pulse, as the battery voltage drops further suddenly the clock mechanic or the electronic will stop working, takes less current so the battery recovers a bit, because the magnet did not used power for a while, and will run again for a while, the pause between two run time will be larger and larger so the clock looks like going slower 73 Alex On 9/12/2014 3:52 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: Dr David Kirkby Managing Director Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT, United Kingdom Registered in England and Wales as company number 08914892 http://www.kirkbymicrowave.co.uk/ Tel 07910 441670 / +44 7910 441670 (0900-2100 GMT) On 12 Sep 2014 12:18, Bob Camp kb...@n1k.org wrote: Hi Hi, If this is an RTC, it’s probably running off of a battery when the machine is powered down. It is far more likely that the oscillator is dropping out (stopping) rather than shifting frequency. Good point, I never thought of that. I have however noticed that analogue quartz clocks slow as the battery goes flat. But maybe too they stop and start. It would make an interesting experiment to check it, but one would need some method of logging the time from the hands. Conceptually that is not difficult, but it needs more work than I want to do. One could do it with a video camera and a fair bit of work writing the software. Probably easier is logging battery voltage and current as that should show if it starts and stops. ___ 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.
Re: [time-nuts] Is a crystal likely to change frequency by 3% ?
The battery probably was going weak and the oscillator coming out of full control by the crystal. The tuning-fork crystal used in RTCs is not as high-Q as a MHz crystal. I have noticed clocks using these can go quite slow at low voltage. The crystal acts more like an inductor in this case and resonates with the increased junction capacitance at low voltage. David On 9/12/14 6:52 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: Dr David Kirkby Managing Director Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT, United Kingdom Registered in England and Wales as company number 08914892 http://www.kirkbymicrowave.co.uk/ Tel 07910 441670 / +44 7910 441670 (0900-2100 GMT) On 12 Sep 2014 12:18, Bob Camp kb...@n1k.org wrote: Hi Hi, If this is an RTC, it’s probably running off of a battery when the machine is powered down. It is far more likely that the oscillator is dropping out (stopping) rather than shifting frequency. Good point, I never thought of that. I have however noticed that analogue quartz clocks slow as the battery goes flat. But maybe too they stop and start. It would make an interesting experiment to check it, but one would need some method of logging the time from the hands. Conceptually that is not difficult, but it needs more work than I want to do. One could do it with a video camera and a fair bit of work writing the software. Probably easier is logging battery voltage and current as that should show if it starts and stops. ___ 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.
Re: [time-nuts] Is a crystal likely to change frequency by 3% ?
On 26 Nov 2012 14:12, David Kirkby david.kir...@onetel.net wrote: I've got an HP 8720D VNA. This has been out of support from Agilent for 8 years, so its getting on a bit. There's a clock in the instrument which keeps the date and time. This is losing about 1 day per month (rough guess), so it has slowed by a bit over 3%. I'm guessing this is likely to be a battery running flat, but are there any other likely causes? I know crystal can jump in frequency, but I'm guessing not by 3%, but perhaps if there was stress in the crystal, it might be. I just noticed this old post of mine. Whatever did cause it to slow about 3% no longer does. It now keeps good time - although definitely not time-nut standard. It probably keeps within a couple of seconds per month, which is good enough. Dr David Kirkby Managing Director Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT, United Kingdom Registered in England and Wales as company number 08914892 http://www.kirkbymicrowave.co.uk/ Tel 07910 441670 / +44 7910 441670 (0900-2100 GMT) ___ 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] Is a crystal likely to change frequency by 3% ?
No that is to much, except if you overdrive it and you are so lucky that after it broke it is still working on a different frequency, but I would suggest check your frequency counter too, because 3% off of a clock frequency wold make the clock almost unusable not just for time nuts... 73 KJ5UHN Dr.Dipl.Ing. Alexander Pummer PCS Consultants Pleasanton CA 94588 On 9/11/2014 3:33 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: On 26 Nov 2012 14:12, David Kirkby david.kir...@onetel.net wrote: I've got an HP 8720D VNA. This has been out of support from Agilent for 8 years, so its getting on a bit. There's a clock in the instrument which keeps the date and time. This is losing about 1 day per month (rough guess), so it has slowed by a bit over 3%. I'm guessing this is likely to be a battery running flat, but are there any other likely causes? I know crystal can jump in frequency, but I'm guessing not by 3%, but perhaps if there was stress in the crystal, it might be. I just noticed this old post of mine. Whatever did cause it to slow about 3% no longer does. It now keeps good time - although definitely not time-nut standard. It probably keeps within a couple of seconds per month, which is good enough. Dr David Kirkby Managing Director Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT, United Kingdom Registered in England and Wales as company number 08914892 http://www.kirkbymicrowave.co.uk/ Tel 07910 441670 / +44 7910 441670 (0900-2100 GMT) ___ 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] Is a crystal likely to change frequency by 3% ?
I've got an HP 8720D VNA. This has been out of support from Agilent for 8 years, so its getting on a bit. There's a clock in the instrument which keeps the date and time. This is losing about 1 day per month (rough guess), so it has slowed by a bit over 3%. I'm guessing this is likely to be a battery running flat, but are there any other likely causes? I know crystal can jump in frequency, but I'm guessing not by 3%, but perhaps if there was stress in the crystal, it might be. It does not help the fact I can't find a service manual for this instrument. It's also a fairly expensive bit of kit (I paid $16,000 a few months back), so I'm not keen to screw it up. If need be, I'll write a bit of code which sets the clock from my computer whenever the GPIB is used. I've no need for precision time keeping on this, but it would be nice to have a copy of the date and time on any printouts. That's not possible when the clock runs so slow. On the off chance anyone does have a service manual for an 8720D, please let me know. I'll buy a copy if need be. There is not one on the Agilent web site - only the user manual. Dave ___ 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] Is a crystal likely to change frequency by 3% ?
David Try here, they have the service guide but no component level info available that I can see. _http://na.tm.agilent.com/8720/document.htm_ (http://na.tm.agilent.com/8720/document.htm) Regards Nigel GM8PZR In a message dated 26/11/2012 14:12:55 GMT Standard Time, david.kir...@onetel.net writes: I've got an HP 8720D VNA. This has been out of support from Agilent for 8 years, so its getting on a bit. There's a clock in the instrument which keeps the date and time. This is losing about 1 day per month (rough guess), so it has slowed by a bit over 3%. I'm guessing this is likely to be a battery running flat, but are there any other likely causes? I know crystal can jump in frequency, but I'm guessing not by 3%, but perhaps if there was stress in the crystal, it might be. It does not help the fact I can't find a service manual for this instrument. It's also a fairly expensive bit of kit (I paid $16,000 a few months back), so I'm not keen to screw it up. If need be, I'll write a bit of code which sets the clock from my computer whenever the GPIB is used. I've no need for precision time keeping on this, but it would be nice to have a copy of the date and time on any printouts. That's not possible when the clock runs so slow. On the off chance anyone does have a service manual for an 8720D, please let me know. I'll buy a copy if need be. There is not one on the Agilent web site - only the user manual. Dave ___ 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.
Re: [time-nuts] Is a crystal likely to change frequency by 3% ?
Hi Simple answer - no. More complicated answer - you can see a crystal jump to a spur, but they are going to be *above* the main mode for a normal clock crystal. If that happens, the clock will run to fast, not to slow. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David Kirkby Sent: Monday, November 26, 2012 9:12 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Is a crystal likely to change frequency by 3% ? I've got an HP 8720D VNA. This has been out of support from Agilent for 8 years, so its getting on a bit. There's a clock in the instrument which keeps the date and time. This is losing about 1 day per month (rough guess), so it has slowed by a bit over 3%. I'm guessing this is likely to be a battery running flat, but are there any other likely causes? I know crystal can jump in frequency, but I'm guessing not by 3%, but perhaps if there was stress in the crystal, it might be. It does not help the fact I can't find a service manual for this instrument. It's also a fairly expensive bit of kit (I paid $16,000 a few months back), so I'm not keen to screw it up. If need be, I'll write a bit of code which sets the clock from my computer whenever the GPIB is used. I've no need for precision time keeping on this, but it would be nice to have a copy of the date and time on any printouts. That's not possible when the clock runs so slow. On the off chance anyone does have a service manual for an 8720D, please let me know. I'll buy a copy if need be. There is not one on the Agilent web site - only the user manual. Dave ___ 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.
Re: [time-nuts] Is a crystal likely to change frequency by 3% ?
Have you contacted ArtekMedia for any manual information? Also, have you checked/posted a question to the VNA Agilent Forum? -John == I've got an HP 8720D VNA. This has been out of support from Agilent for 8 years, so its getting on a bit. There's a clock in the instrument which keeps the date and time. This is losing about 1 day per month (rough guess), so it has slowed by a bit over 3%. I'm guessing this is likely to be a battery running flat, but are there any other likely causes? I know crystal can jump in frequency, but I'm guessing not by 3%, but perhaps if there was stress in the crystal, it might be. It does not help the fact I can't find a service manual for this instrument. It's also a fairly expensive bit of kit (I paid $16,000 a few months back), so I'm not keen to screw it up. If need be, I'll write a bit of code which sets the clock from my computer whenever the GPIB is used. I've no need for precision time keeping on this, but it would be nice to have a copy of the date and time on any printouts. That's not possible when the clock runs so slow. On the off chance anyone does have a service manual for an 8720D, please let me know. I'll buy a copy if need be. There is not one on the Agilent web site - only the user manual. Dave ___ 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.
Re: [time-nuts] Is a crystal likely to change frequency by 3% ?
On 26 November 2012 16:00, J. Forster j...@quikus.com wrote: Have you contacted ArtekMedia for any manual information? No. First I'll try to get a free one! Also, have you checked/posted a question to the VNA Agilent Forum? Yes. Only a few hours ago (just before I posted on time-nuts I think), so still chance that will come up with something. -John Dave ___ 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.
