Re: [time-nuts] hp 10544A and 10811A ovenized oscillators
Hi A failed ( = cold) oven on either a normal OCXO should give you a “tens of ppm” sort of frequency error. At 10 MHz that would be over 100 Hz. Fractions of a ppm are less likely to be oven issues. Bob > On Nov 5, 2018, at 1:01 PM, Dr. Frank wrote: > > Walter, > > did you check on both failing oscillators, that the ovens work properly > afterwards, or that the cases still get warm? > > I once had a failing 10811, where the NTC was defect, maybe also after a > longer unused time. > > As the heater draw an excessive current on turning on, (about 500mA for the > 10811), maybe the thermal fuse blew up, but due to the peaking current, not > due to temperature. > > I find it quite unusal, that the oscillator / XTAL itself should make a jump > like this. > After 48h at most, it should return to its recent frequency trimming, within > < 1E-8, or less.. as these guys are really old. > > That's the typical behavior of all three 10811, which I own (inside 5370B, > 5335A, and one external). > > Frank > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] hp 10544A and 10811A ovenized oscillators
Wow, I am surprised they allowed two weeks of playing around on an SSBN. I would have thought that on something like that the Navy would just replace it immediately. I was only in one once and I was real impressed by the professionalism of the crew. 73 - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 848-245-9115 -Original Message- From: time-nuts On Behalf Of Glenn Little WB4UIV Sent: Saturday, November 3, 2018 7:10 PM To: time-nuts@lists.febo.com Subject: Re: [time-nuts] hp 10544A and 10811A ovenized oscillators I had to "fix" a HP Cesium standard oscillator while on an SSBN. The problem was a failed op amp in the control circuit for the crystal oscillator. Due to lack of parts, the "fix" was to run the standard open loop with nothing controlling the crystal oscillator. Using an oscilloscope to compare the good standard with the open loop standard, I I was able to adjust the failed standard oscillator. It took over two weeks of adjusting the failed standard oscillator to keep the Lissajous pattern stable. The oven was off for a total of less than an hour during troubleshooting. Prior to failure the standard operated correctly for many months. I was surprised as to the amount of time for the oscillator to settle down. Glenn ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] hp 10544A and 10811A ovenized oscillators
I had to "fix" a HP Cesium standard oscillator while on an SSBN. The problem was a failed op amp in the control circuit for the crystal oscillator. Due to lack of parts, the "fix" was to run the standard open loop with nothing controlling the crystal oscillator. Using an oscilloscope to compare the good standard with the open loop standard, I I was able to adjust the failed standard oscillator. It took over two weeks of adjusting the failed standard oscillator to keep the Lissajous pattern stable. The oven was off for a total of less than an hour during troubleshooting. Prior to failure the standard operated correctly for many months. I was surprised as to the amount of time for the oscillator to settle down. Glenn On 11/2/2018 4:44 PM, Mark Sims wrote: How long had the osc been powered up since taking it out of storage? It can take an OCXO typically 4-6 weeks of constant power-on after long-term storage before the drift settles down. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. -- --- Glenn LittleARRL Technical Specialist QCWA LM 28417 Amateur Callsign: WB4UIVwb4...@arrl.netAMSAT LM 2178 QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR "It is not the class of license that the Amateur holds but the class of the Amateur that holds the license" ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] hp 10544A and 10811A ovenized oscillators
HI I have had experience with two 10811 oscillators which turned out to have the same problem. Inside there is a gold plated ferule mounted in teflon at the junction of the tuning diode and the transistor, obviously considered a very high impedance point, or may be just sensitive to leakage. In both cases the joint was not soldered. A touch of solder and they behaved perfectly. Before, they did not respond to the adjusting voltage. Thinking about it again, maybe the diodes were variable, so they assembled the oscillator so that the oven could operate, to see if they covered a tuning range test. If they did not they could change the diode. If they forgot, they did not go back and solder the joint. I have been feeling bad for some years as I bought a 10811 from a ham on the popular trading site, and when I complined that it was out of range and would not tune he refunded my money. A few months later, when a previously good unit failed, and I did a post mortem, I found the problem, and checking the first bad unit it had the same problem. When I looked for the ID of the guy who sold it to me I could not find it, and I feel I owe him the price. After all he was a ham, not some shonky dealer. So if two samples in four units I have had the fault, it is worth checking if troubles appear. cheers, Neville Michie > On 3 Nov 2018, at 06:15, Bob kb8tq wrote: > > Hi > > The change is suspiciously close to the electrical tuning range of a typical > HP OCXO. > The answer may be a failure of the bias on the EFC line ….. > > Bob > >> On Nov 2, 2018, at 2:51 PM, Walter Shawlee 2 wrote: >> >> I have several of these as the -010 high stability timebase options >> in my various HP counters, and generally they work very well, with >> usual errors under 0.01Hz and very minor drift over time. >> >> a few months ago, I had a power interruption, and black out for a few hours, >> along with the usual erratic restart from the power company. shortly >> afterwards, I built a nice little >> homemade TM500 plug-in OCXO unit to fit on my bench, and without giving it >> much thought, used >> my bench standard (an hp 435B-K26 power/frequency reference with an internal >> 10544A) to cal it. all seemed good. >> >> soon after, I was working on an hp 5334A counter, and added a 10811A as as >> upgrade from my >> spares and suddenly, I had a big 1.3Hz error at 10Mhz when I cross checked >> it to my bench references AND a rubidium. I brought over my recently cal'd >> rubidium from the upstairs lab, and yes, there was now clearly a big step >> error. my upstairs 5335A with a 10811A had the same step effect! >> >> these 2 units are always on for stability, so both got cycled the same way >> during the power failure. >> >> it seems that the power failure cycle had bumped the internal 10544A >> oscillator inside the 435 by that amount, as well as the 10811A inside the >> 5335A. I have never seen that effect before, both the ovenized osicllators >> from hp have been very reliable for me, so I thought I would put that info >> out in case anyone else has seen this effect and knows the cause. >> >> using the rubidium (which I keep off until I need it, and wait for at least >> 2 hours for best settling), I reset everything back to a flat 10Mhz, and all >> was well, except that the first 10811A I put in the 5334A conked out (oven >> still fine, but the oscillator went dead, giving the dreaded "no osc" >> message on the counter). another spare fixed that, and two days of drift >> testing to get everything back where it belongs. anybody want the bad >> 10811A? >> >> anyway, just thought the information might be handy for others. the EFC >> range on the 10811A/10544A is *only 1Hz*, so such a big jump is unusual to >> say the least. it required the main coarse adjustment to fix. >> The 435B-K26 is a pretty remarkable widget if you ever see one, it makes a >> great 10Mhz reference and 1mW power reference in one little box, very useful >> for an RF bench. One of hp's rare and forgotten treasures. >> >> all the best, >> walter >> >> -- >> Walter Shawlee 2 >> Sphere Research Corp. 3394 Sunnyside Rd. >> West Kelowna, BC, V1Z 2V4 CANADA >> Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca >> We're all in one boat, no matter how it looks to you. (WS2) >> All you need is love. (John Lennon) >> But, that doesn't mean other things don't come in handy. (WS2) >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list --
Re: [time-nuts] hp 10544A and 10811A ovenized oscillators
Hi. I don't have a good answer to why both of your oscillators would have drifted at once after the power cutout. However, I would be very interested in taking a look at the bad 10811A. I have always been fascinated by these and have wanted to take one apart (and try and understand/fix it) for several years but I have never been (un?)lucky enough to get my hands on a broken one. I am happy to pay for shipping if you are interested. Matthew > On Nov 2, 2018, at 11:51 AM, Walter Shawlee 2 wrote: > > anybody want the bad 10811A? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] hp 10544A and 10811A ovenized oscillators
Hi The change is suspiciously close to the electrical tuning range of a typical HP OCXO. The answer may be a failure of the bias on the EFC line ….. Bob > On Nov 2, 2018, at 2:51 PM, Walter Shawlee 2 wrote: > > I have several of these as the -010 high stability timebase options > in my various HP counters, and generally they work very well, with > usual errors under 0.01Hz and very minor drift over time. > > a few months ago, I had a power interruption, and black out for a few hours, > along with the usual erratic restart from the power company. shortly > afterwards, I built a nice little > homemade TM500 plug-in OCXO unit to fit on my bench, and without giving it > much thought, used > my bench standard (an hp 435B-K26 power/frequency reference with an internal > 10544A) to cal it. all seemed good. > > soon after, I was working on an hp 5334A counter, and added a 10811A as as > upgrade from my > spares and suddenly, I had a big 1.3Hz error at 10Mhz when I cross checked it > to my bench references AND a rubidium. I brought over my recently cal'd > rubidium from the upstairs lab, and yes, there was now clearly a big step > error. my upstairs 5335A with a 10811A had the same step effect! > > these 2 units are always on for stability, so both got cycled the same way > during the power failure. > > it seems that the power failure cycle had bumped the internal 10544A > oscillator inside the 435 by that amount, as well as the 10811A inside the > 5335A. I have never seen that effect before, both the ovenized osicllators > from hp have been very reliable for me, so I thought I would put that info > out in case anyone else has seen this effect and knows the cause. > > using the rubidium (which I keep off until I need it, and wait for at least 2 > hours for best settling), I reset everything back to a flat 10Mhz, and all > was well, except that the first 10811A I put in the 5334A conked out (oven > still fine, but the oscillator went dead, giving the dreaded "no osc" message > on the counter). another spare fixed that, and two days of drift testing to > get everything back where it belongs. anybody want the bad 10811A? > > anyway, just thought the information might be handy for others. the EFC > range on the 10811A/10544A is *only 1Hz*, so such a big jump is unusual to > say the least. it required the main coarse adjustment to fix. > The 435B-K26 is a pretty remarkable widget if you ever see one, it makes a > great 10Mhz reference and 1mW power reference in one little box, very useful > for an RF bench. One of hp's rare and forgotten treasures. > > all the best, > walter > > -- > Walter Shawlee 2 > Sphere Research Corp. 3394 Sunnyside Rd. > West Kelowna, BC, V1Z 2V4 CANADA > Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca > We're all in one boat, no matter how it looks to you. (WS2) > All you need is love. (John Lennon) > But, that doesn't mean other things don't come in handy. (WS2) > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
