Re: [time-nuts] MTI 260-0624-D OCXO
Bob, The vendor has said that they did not want the unit back. So... I opened it up. Crudely, I admit. I learned a few things. I was concerned about the outer case heating up too much when I was trying to remove the solder. Turns out that the outer case doesn't touch anything except the pins, so it can get pretty hot without any damage. Unfortunately, I used a bit of brute force to remove the casing after scraping away as much of the solder as I could and after cracking the solder seal with a hammer and screw driver. Even using more heat, I'm not sure of the best way to remove the case. Neither solder wick nor a vacuum desoldering tool is likely to remove all of the solder between the top case and the bottom. Even so, I got the case off. Somewhat bent, even bent the bottom circuit board a bit. I discovered that there is a 2mm hole in the top that allows a variable resistor to be adjusted. You need a pretty long, small screwdriver / adjusting tool to do that, but that is probably for setting the center point. I would try to remove the solder rather than drilling, or drill upside down to prevent solder flakes from falling inside. Also, I found that the -D on my part number appears to correspond to the board revision, which is marked "Rev D". So the -C and -D parts probably have the same specifications. And, on the inside there is a marking "92.0" which I believe would be the set point for this specific crystal. So if I took the crystal out, I would know where to design the set point for a custom unit (currently beyond my skills, but who knows...). >From there, I removed the bottom casing. That caused additional damage, some lifted traces and even one very small part (tiny, SMD, who knows?). But, I then soldered wires directly to the board, making patches for the lifted traces. I plugged it in. I turned it on. Success! I gave it 12v which should supply 2A, but it dropped the voltage down to just over 9V. Even so, I got a nice sine wave out at around 4.999790Mhz according to my (uncalibrated) scope and around 800mV (into 50 ohm, DC). That was with nothing attached to the adjustment pin. After some time, the frequency stabilized at 5.14Mhz and the voltage came back up to 10v. When I attached the adjustment pin to ground, there was no change. When I attached the adjustment pin to Vref (which is at 6.15v), the frequency dropped to 5.10Mhz. So apparently, these units adjust negatively. But also have a very wide adjustment range of 4Hz (8e-7). I am assuming that the adjustment range is 0..6v. I attached the adjustment pin to +10v and the frequency dropped another 3Hz for a 1.4e-6 adjustment range. I don't expect that this specific unit will be very useful given the damage that I caused opening it up. But, probably there were just bad connections internally, so if I were much more careful in the disassembly, I could probably have fixed it. Something to keep in mind for the next unit. I may be wrong for what the variable resistor does. Turning it made no difference in the frequency. I also suspect, but don't know that the difference from 5Mhz is due to the frequency counter being uncalibrated. It could also because I damaged the unit or just because it is very far off from where it should be. Still, I learned a lot, and well worth the time spent. Mike > Hi > The one advantage you have in testing a used OCXO is you have a pretty good > idea of how > you are going to use it. If phase noise does not matter to you … no need to > test. I’d always check > that it tunes on freq with reasonable EFC range left over. I’d also make sure > that it warms up > properly (oven works) and that it has a reasonable output. What goes on the > list past that … > it depends on what you need. > The gear you have will check aging and get it set on frequency fine. It will > check it for “wander” > as your lab heats up and cools down. With a GPSDO and a simple phase lock, a > DVM may be > all you really need to do most of that. You will not have a proper ADEV, but > you will know it works > pretty well (or not ..). > A lightbulb oven / bench / fridge /freezer proces can give you a wide range > TC if you need it. > If you do get into phase noise, a sound card system will get you going. For > ADEV, the 10811’s > tune far enough that a single mixer system with your 53131 will give you good > data. Both > of those will involve some building, but not a lot of money. > There is one thing about the 10811’s: They are not sealed units. They tend to > soak up humidity > when stored in most parts of the country. You may want to run them for a > month or three > before doing any fancy testing. > Bob >> On Feb 18, 2016, at 7:40 AM, Adrian Godwin wrote: >> >> I have a small collection of 10811 and similar oscillators here, collected >> from hamfests rather than china (and mostly pre-ebay). >> >> What sort of testing regime would you put them through ? I don't have >> anything as exotic as a timepod but I do
Re: [time-nuts] MTI 260-0624-D OCXO
Hi The one advantage you have in testing a used OCXO is you have a pretty good idea of how you are going to use it. If phase noise does not matter to you … no need to test. I’d always check that it tunes on freq with reasonable EFC range left over. I’d also make sure that it warms up properly (oven works) and that it has a reasonable output. What goes on the list past that … it depends on what you need. The gear you have will check aging and get it set on frequency fine. It will check it for “wander” as your lab heats up and cools down. With a GPSDO and a simple phase lock, a DVM may be all you really need to do most of that. You will not have a proper ADEV, but you will know it works pretty well (or not ..). A lightbulb oven / bench / fridge /freezer proces can give you a wide range TC if you need it. If you do get into phase noise, a sound card system will get you going. For ADEV, the 10811’s tune far enough that a single mixer system with your 53131 will give you good data. Both of those will involve some building, but not a lot of money. There is one thing about the 10811’s: They are not sealed units. They tend to soak up humidity when stored in most parts of the country. You may want to run them for a month or three before doing any fancy testing. Bob > On Feb 18, 2016, at 7:40 AM, Adrian Godwin wrote: > > I have a small collection of 10811 and similar oscillators here, collected > from hamfests rather than china (and mostly pre-ebay). > > What sort of testing regime would you put them through ? I don't have > anything as exotic as a timepod but I do have an HP53131A, the Tait Rb > source, and a KS-24361 set up. And always keen to get hints on the > acquisition of new toys ! > > > > On Thu, Feb 18, 2016 at 12:09 PM, Bob Camp wrote: > >> Hi >> >> It is *much* better to have an OCXO that you do not need to test to death. >> There is simply to much testing to do. A modern factory does not test the >> quality into the product (of any sort) they design in and build it in. The >> same >> is true of the normal customer for virtually any component. They make sure >> the parts come from somebody they can trust and save a lot of testing time. >> >> That said, yes, I have a pile of scrap parts sitting in front of me as I >> type this. >> It’s a hobby. Time does not count. It lets me play with all sorts of toys >> doing >> the testing. I occasionally learn things in the process. Mostly I learn >> that >> my hope of a 100% perfect batch is still a dream …. >> >> Bob >> >> >> >>> On Feb 17, 2016, at 9:56 PM, time...@metachaos.net wrote: >>> >>> Bob, >>> >>> In this case, I know how it was taken off the board - it wasn't. They >> just cut >>> the board around it. I had to remove it myself. Nice thing about that, >> is that >>> I got a nice plastic, pre-formed part that fits between the board and the >>> OCXO, probably as an insulator. >>> >>> You are also right about the number of things that you need to test to >> make >>> sure that one of these is fully functional. However, this is a "starter" >> OCXO >>> for me and I don't yet have the equipment to perform the tests. The best >> that >>> I can do is to make sure that, when powered up >>> >>> 1. I see something that sort of looks like a sine wave at a reasonable >>> magnitude. >>> >>> 2. My 2465B CT frequency counter thinks that it is somewhere near 5Mhz. >>> >>> 3. If I apply gnd, or VRef to the adjustment pin I see the frequency >> change >>> at least a small amount. >>> >>> Without more equipment, there isn't much more that I can do to test. >> Unless >>> you have some suggestions? >>> >>> >>> Mike >>> >>> Hi >>> Best guess is these things get taken off the board with either a big >> torch or a charcoal fire. You can ask Mr Google to dig up pictures of the process. Depending on >> just how quick they are, the insides of the OCXO can easily be reflowed. The >> likelihood of it reflowing and cooling back to a reliable joint … not real good. >>> Bob >>> > On Feb 17, 2016, at 5:16 AM, Andrea Baldoni >> wrote: > > On Tue, Feb 16, 2016 at 07:58:21PM -0500, time...@metachaos.net wrote: > >> I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After >> testing it, >> it is clear that it is defective. >> >> 1. It never heats up. >> 2. The reference voltage is zero. >> 3. Only noise is seen on the output pin. > > I had the same issue with some of them. It's very likely that the >> internal > solder connections from pins to PCB are broken, at least, the one for >> power. > It happens because the inner oven is heavy and there isn't any thermal > insulator (besides air) to keep it from moving. > > Wheter the crystal has been damaged or not, it's unknown. I had one >> where the > crystal actually fell off from its supports too. > > I posted a link to photos of the internals, time ago. Th
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This tube type item on ebay is equipped with E1T high speed decade counting tubes. 222022951573 I'm not affiliated, etc... Antonio i8iov ___ 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] MTI 260-0624-D OCXO
Bob is point on Said another way ...few of us consider the value of our time in these projects ..Lets say your personal time is worth $50/hour (cheap cheap for a professional today) let's say you have to spend 10 hours testing this oscillator that puts the real cost of the oscillator at $500+ suddenly some things don't look like such good bargains. The other side of the coin is that if you learn something new about oscillators and their behavior and the supporting electronics circuitry then $500 is a cheap educational seminar . Dave NR1DX On 2/18/2016 7:09 AM, Bob Camp wrote: Hi It is*much* better to have an OCXO that you do not need to test to death. There is simply to much testing to do. A modern factory does not test the quality into the product (of any sort) they design in and build it in. The same is true of the normal customer for virtually any component. They make sure the parts come from somebody they can trust and save a lot of testing time. That said, yes, I have a pile of scrap parts sitting in front of me as I type this. It’s a hobby. Time does not count. It lets me play with all sorts of toys doing the testing. I occasionally learn things in the process. Mostly I learn that my hope of a 100% perfect batch is still a dream …. Bob -- Dave manu...@artekmanuals.com www.ArtekManuals.com --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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] MTI 260-0624-D OCXO
I have a small collection of 10811 and similar oscillators here, collected from hamfests rather than china (and mostly pre-ebay). What sort of testing regime would you put them through ? I don't have anything as exotic as a timepod but I do have an HP53131A, the Tait Rb source, and a KS-24361 set up. And always keen to get hints on the acquisition of new toys ! On Thu, Feb 18, 2016 at 12:09 PM, Bob Camp wrote: > Hi > > It is *much* better to have an OCXO that you do not need to test to death. > There is simply to much testing to do. A modern factory does not test the > quality into the product (of any sort) they design in and build it in. The > same > is true of the normal customer for virtually any component. They make sure > the parts come from somebody they can trust and save a lot of testing time. > > That said, yes, I have a pile of scrap parts sitting in front of me as I > type this. > It’s a hobby. Time does not count. It lets me play with all sorts of toys > doing > the testing. I occasionally learn things in the process. Mostly I learn > that > my hope of a 100% perfect batch is still a dream …. > > Bob > > > > > On Feb 17, 2016, at 9:56 PM, time...@metachaos.net wrote: > > > > Bob, > > > > In this case, I know how it was taken off the board - it wasn't. They > just cut > > the board around it. I had to remove it myself. Nice thing about that, > is that > > I got a nice plastic, pre-formed part that fits between the board and the > > OCXO, probably as an insulator. > > > > You are also right about the number of things that you need to test to > make > > sure that one of these is fully functional. However, this is a "starter" > OCXO > > for me and I don't yet have the equipment to perform the tests. The best > that > > I can do is to make sure that, when powered up > > > > 1. I see something that sort of looks like a sine wave at a reasonable > > magnitude. > > > > 2. My 2465B CT frequency counter thinks that it is somewhere near 5Mhz. > > > > 3. If I apply gnd, or VRef to the adjustment pin I see the frequency > change > > at least a small amount. > > > > Without more equipment, there isn't much more that I can do to test. > Unless > > you have some suggestions? > > > > > > Mike > > > > > >> Hi > > > >> Best guess is these things get taken off the board with either a big > torch or a charcoal fire. > >> You can ask Mr Google to dig up pictures of the process. Depending on > just how quick > >> they are, the insides of the OCXO can easily be reflowed. The > likelihood of it reflowing and > >> cooling back to a reliable joint … not real good. > > > >> Bob > > > >>> On Feb 17, 2016, at 5:16 AM, Andrea Baldoni > wrote: > >>> > >>> On Tue, Feb 16, 2016 at 07:58:21PM -0500, time...@metachaos.net wrote: > >>> > I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After > testing it, > it is clear that it is defective. > > 1. It never heats up. > 2. The reference voltage is zero. > 3. Only noise is seen on the output pin. > >>> > >>> I had the same issue with some of them. It's very likely that the > internal > >>> solder connections from pins to PCB are broken, at least, the one for > power. > >>> It happens because the inner oven is heavy and there isn't any thermal > >>> insulator (besides air) to keep it from moving. > >>> > >>> Wheter the crystal has been damaged or not, it's unknown. I had one > where the > >>> crystal actually fell off from its supports too. > >>> > >>> I posted a link to photos of the internals, time ago. The link is dead > now > >>> and I don't think to have the photos anymore but perhaps someone > downloaded > >>> them. > >>> > >>> Best regards, > >>> Andrea Baldoni > >>> ___ > >>> 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. > > > > > > > > -- > > Best regards, > > Timenutmailto:time...@metachaos.net > > > > ___ > > 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 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] MTI 260-0624-D OCXO
Hi It is *much* better to have an OCXO that you do not need to test to death. There is simply to much testing to do. A modern factory does not test the quality into the product (of any sort) they design in and build it in. The same is true of the normal customer for virtually any component. They make sure the parts come from somebody they can trust and save a lot of testing time. That said, yes, I have a pile of scrap parts sitting in front of me as I type this. It’s a hobby. Time does not count. It lets me play with all sorts of toys doing the testing. I occasionally learn things in the process. Mostly I learn that my hope of a 100% perfect batch is still a dream …. Bob > On Feb 17, 2016, at 9:56 PM, time...@metachaos.net wrote: > > Bob, > > In this case, I know how it was taken off the board - it wasn't. They just cut > the board around it. I had to remove it myself. Nice thing about that, is that > I got a nice plastic, pre-formed part that fits between the board and the > OCXO, probably as an insulator. > > You are also right about the number of things that you need to test to make > sure that one of these is fully functional. However, this is a "starter" OCXO > for me and I don't yet have the equipment to perform the tests. The best that > I can do is to make sure that, when powered up > > 1. I see something that sort of looks like a sine wave at a reasonable > magnitude. > > 2. My 2465B CT frequency counter thinks that it is somewhere near 5Mhz. > > 3. If I apply gnd, or VRef to the adjustment pin I see the frequency change > at least a small amount. > > Without more equipment, there isn't much more that I can do to test. Unless > you have some suggestions? > > > Mike > > >> Hi > >> Best guess is these things get taken off the board with either a big torch >> or a charcoal fire. >> You can ask Mr Google to dig up pictures of the process. Depending on just >> how quick >> they are, the insides of the OCXO can easily be reflowed. The likelihood of >> it reflowing and >> cooling back to a reliable joint … not real good. > >> Bob > >>> On Feb 17, 2016, at 5:16 AM, Andrea Baldoni wrote: >>> >>> On Tue, Feb 16, 2016 at 07:58:21PM -0500, time...@metachaos.net wrote: >>> I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing it, it is clear that it is defective. 1. It never heats up. 2. The reference voltage is zero. 3. Only noise is seen on the output pin. >>> >>> I had the same issue with some of them. It's very likely that the internal >>> solder connections from pins to PCB are broken, at least, the one for power. >>> It happens because the inner oven is heavy and there isn't any thermal >>> insulator (besides air) to keep it from moving. >>> >>> Wheter the crystal has been damaged or not, it's unknown. I had one where >>> the >>> crystal actually fell off from its supports too. >>> >>> I posted a link to photos of the internals, time ago. The link is dead now >>> and I don't think to have the photos anymore but perhaps someone downloaded >>> them. >>> >>> Best regards, >>> Andrea Baldoni >>> ___ >>> 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. > > > > -- > Best regards, > Timenutmailto:time...@metachaos.net > > ___ > 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.
