I bought an Isotemp OCXO82-59 with a frequency of 10 MHz for a $3 at the MIT flea market. As expected it was dead. It heats up as expected but looking at the output with a scope there is nothing. However looking at the output with a spectrum analyzer I can see a faint 10 MHz signal. It seems that the oscillator is running but the output circuitry is dead. Reasonable assumption? Anyway, has anyone had any luck unsoldering the tin case without destroying it? Pete.

Pete Another MIT-er. Well the only way I have handled them is with a small torch. Clamp the unit. Heat the solder and it will flow down to the low point and tend to drip out. Stick a small xacto knife in to break any remaining solder loose. Not super pretty but all of it can be cleaned up usually and then re-soldered. Hey its dead whats to loose? Regards Paul WB8TSL On Tue, Oct 18, 2016 at 9:11 AM, Peter Reilley <preilley_454@comcast.net> wrote: > I bought an Isotemp OCXO82-59 with a frequency of 10 MHz for a $3 at the > MIT flea market. > As expected it was dead. It heats up as expected but looking at the > output with a scope there > is nothing. However looking at the output with a spectrum analyzer I can > see a faint 10 MHz > signal. It seems that the oscillator is running but the output circuitry > is dead. Reasonable > assumption? > > Anyway, has anyone had any luck unsoldering the tin case without > destroying it? > > Pete. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. >

Pete, I'm not familiar with your OCXO but I found one shown on 'theBay' (item 261920574725) and it appeared to have an option for 'mounting screws', four of them, on the bottom. Interestingly, the 'link' to the datasheet for that unit did not show threads for mounting screws. If your unit has that option, I would suggest placing four long screws, mounting the item in a vise, use a small torch (I've used a hand held propane torch turned down very low to open a number of units from 5061A's) around the bottom of the case while gripping the top with an appropriate sized Channel Lock plier and lifting off the top. If you can repair the OCXO, it should be easy to reassemble the unit with solder. TheBay unit looks like it has a screw cover (which likely has a rubber gasket) for mechanical adjustment of the frequency. I'd remove that before applying the torch. :^). If you get it open, I'd love to see some pictures of the insides. Good luck and hope this helps. Joe -----Original Message----- From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Peter Reilley Sent: Tuesday, October 18, 2016 8:11 AM To: time-nuts@febo.com Subject: [time-nuts] Opening an Isotemp OCXO I bought an Isotemp OCXO82-59 with a frequency of 10 MHz for a $3 at the MIT flea market. As expected it was dead. It heats up as expected but looking at the output with a scope there is nothing. However looking at the output with a spectrum analyzer I can see a faint 10 MHz signal. It seems that the oscillator is running but the output circuitry is dead. Reasonable assumption? Anyway, has anyone had any luck unsoldering the tin case without destroying it? Pete. _______________________________________________ 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.

I got one open without too much much trouble with a propane torch. Work fast, use gravity and have something pointy to pry with as you go. -ch 73 de ai6kg On Oct 18, 2016 6:14 AM, "Peter Reilley" <preilley_454@comcast.net> wrote: > I bought an Isotemp OCXO82-59 with a frequency of 10 MHz for a $3 at the > MIT flea market. > As expected it was dead. It heats up as expected but looking at the > output with a scope there > is nothing. However looking at the output with a spectrum analyzer I can > see a faint 10 MHz > signal. It seems that the oscillator is running but the output circuitry > is dead. Reasonable > assumption? > > Anyway, has anyone had any luck unsoldering the tin case without > destroying it? > > Pete. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. >

I did finally get it open. I used a very large old style soldering iron and .003 inch steel shim stock. I would melt the solder on the straight seams and insert small pieces of the shim. Solder does not stick well to steel so the shim kept the soldered seam open. I used a soldering iron rather than a torch because I can control the temperature. I could not use the shim at the corners. After all the straight seams were separated I could pull each corner using a screw in the mounting hole and melt the solder at the corner. Slowly working my way around, corner by corner, I got it opened. I did not damage anything so I should be able to close it up after I fix it. Looking around with my scope it seems that the output driver chip is bad as I expected. It is a TI 14 pin surface mount DIP. It says S30 on it which if it is a 74S30 it is an 8 input positive NAND gate. The board layout confirms this as the 10 MHz signal is connected to pin 2 and all other inputs are tied high. Pin 8 is connected to the output. The chip is run off 12 volts so it must be CMOS. But I cannot find any chip like that that will run off 12 volts. Any suggestions for a replacement? Also, using an 8 input NAND chip for a driver seems an odd choice. When I put 12 volts on the unit the S30 chip gets really hot. After I removed the chip the unit seems to work OK. The current jumps between about .1 amp to .9 amps. It seems like the temperature regulator is an on/off type controller. The device on eBay, item 261920574725, looks exactly like what I have. I have placed a bunch of pictures in my dropbox. https://www.dropbox.com/sh/52e9d1rva9kpb3w/AABmbIj1aK7Zk2J9SNMmu-JAa?dl=0 Pete. On 10/18/2016 10:57 AM, J. L. Trantham wrote: > Pete, > > I'm not familiar with your OCXO but I found one shown on 'theBay' (item 261920574725) and it appeared to have an option for 'mounting screws', four of them, on the bottom. Interestingly, the 'link' to the datasheet for that unit did not show threads for mounting screws. > > If your unit has that option, I would suggest placing four long screws, mounting the item in a vise, use a small torch (I've used a hand held propane torch turned down very low to open a number of units from 5061A's) around the bottom of the case while gripping the top with an appropriate sized Channel Lock plier and lifting off the top. > > If you can repair the OCXO, it should be easy to reassemble the unit with solder. > > TheBay unit looks like it has a screw cover (which likely has a rubber gasket) for mechanical adjustment of the frequency. I'd remove that before applying the torch. :^). > > If you get it open, I'd love to see some pictures of the insides. > > Good luck and hope this helps. > > Joe > > > > -----Original Message----- > From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Peter Reilley > Sent: Tuesday, October 18, 2016 8:11 AM > To: time-nuts@febo.com > Subject: [time-nuts] Opening an Isotemp OCXO > > I bought an Isotemp OCXO82-59 with a frequency of 10 MHz for a $3 at the MIT flea market. > As expected it was dead. It heats up as expected but looking at the > output with a scope there > is nothing. However looking at the output with a spectrum analyzer I > can see a faint 10 MHz > signal. It seems that the oscillator is running but the output > circuitry is dead. Reasonable > assumption? > > Anyway, has anyone had any luck unsoldering the tin case without destroying it? > > Pete. > > _______________________________________________ > 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. > >

-------- In message <10a3ea7d-37f0-51bc-2470-35645d767bbd@comcast.net>, Peter Reilley writes: >The chip is run off 12 volts so it must be CMOS. Or the OCXO is not a 12V model ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.

The only document that I could find said 12 volt. Pete. On 10/28/2016 11:49 AM, Poul-Henning Kamp wrote: > -------- > In message <10a3ea7d-37f0-51bc-2470-35645d767bbd@comcast.net>, Peter Reilley writes: > >> The chip is run off 12 volts so it must be CMOS. > Or the OCXO is not a 12V model ? > >

The OCXO82-59 datasheet lists 12V supply, 5V clock out, could also be a blown regulator in your ocxo, if it is indeed a 12v model. On Friday, 28 October 2016, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote: > -------- > In message <10a3ea7d-37f0-51bc-2470-35645d767bbd@comcast.net > <javascript:;>>, Peter Reilley writes: > > >The chip is run off 12 volts so it must be CMOS. > > Or the OCXO is not a 12V model ? > > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > phk@FreeBSD.ORG | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com <javascript:;> > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. >

That's one sweet soldering iron. Is it an American Beauty ? On Fri, Oct 28, 2016 at 4:31 PM, Peter Reilley <preilley_454@comcast.net> wrote: > I did finally get it open. I used a very large old style soldering > iron and .003 inch steel shim stock. I would melt the solder on the > straight seams and insert small pieces of the shim. Solder does not > stick well to steel so the shim kept the soldered seam open. > I used a soldering iron rather than a torch because I can control the > temperature. > > I could not use the shim at the corners. After all the straight seams > were separated I could pull each corner using a screw in the mounting > hole and melt the solder at the corner. Slowly working my way around, > corner by corner, I got it opened. I did not damage anything so I > should be able to close it up after I fix it. > > Looking around with my scope it seems that the output driver chip is bad > as I expected. It is a TI 14 pin surface mount DIP. It says S30 on it > which if it is a 74S30 it is an 8 input positive NAND gate. The board > layout confirms this as the 10 MHz signal is connected to pin 2 and all > other inputs are tied high. Pin 8 is connected to the output. > > The chip is run off 12 volts so it must be CMOS. But I cannot find any > chip like that that will run off 12 volts. Any suggestions for a > replacement? > > Also, using an 8 input NAND chip for a driver seems an odd choice. > > When I put 12 volts on the unit the S30 chip gets really hot. After I > removed the chip the unit seems to work OK. The current jumps between > about .1 amp to .9 amps. It seems like the temperature regulator is > an on/off type controller. > > The device on eBay, item 261920574725, looks exactly like what I have. > > I have placed a bunch of pictures in my dropbox. > https://www.dropbox.com/sh/52e9d1rva9kpb3w/AABmbIj1aK7Zk2J9SNMmu-JAa?dl=0 > > Pete. > > > > > On 10/18/2016 10:57 AM, J. L. Trantham wrote: > >> Pete, >> >> I'm not familiar with your OCXO but I found one shown on 'theBay' (item >> 261920574725) and it appeared to have an option for 'mounting screws', four >> of them, on the bottom. Interestingly, the 'link' to the datasheet for >> that unit did not show threads for mounting screws. >> >> If your unit has that option, I would suggest placing four long screws, >> mounting the item in a vise, use a small torch (I've used a hand held >> propane torch turned down very low to open a number of units from 5061A's) >> around the bottom of the case while gripping the top with an appropriate >> sized Channel Lock plier and lifting off the top. >> >> If you can repair the OCXO, it should be easy to reassemble the unit with >> solder. >> >> TheBay unit looks like it has a screw cover (which likely has a rubber >> gasket) for mechanical adjustment of the frequency. I'd remove that before >> applying the torch. :^). >> >> If you get it open, I'd love to see some pictures of the insides. >> >> Good luck and hope this helps. >> >> Joe >> >> >> >> -----Original Message----- >> From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Peter >> Reilley >> Sent: Tuesday, October 18, 2016 8:11 AM >> To: time-nuts@febo.com >> Subject: [time-nuts] Opening an Isotemp OCXO >> >> I bought an Isotemp OCXO82-59 with a frequency of 10 MHz for a $3 at the >> MIT flea market. >> As expected it was dead. It heats up as expected but looking at the >> output with a scope there >> is nothing. However looking at the output with a spectrum analyzer I >> can see a faint 10 MHz >> signal. It seems that the oscillator is running but the output >> circuitry is dead. Reasonable >> assumption? >> >> Anyway, has anyone had any luck unsoldering the tin case without >> destroying it? >> >> Pete. >> >> _______________________________________________ >> 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/m > ailman/listinfo/time-nuts > and follow the instructions there. >

When I have an unknown OCXO, I put a scope on the output and connect a bench power supply to the DC inputs. I bring up the voltage until the RF out hits a stable level. That is where the internal regulator starts regulating. Then set it to the nearest normal power supply voltage, +5, +12, +15, +24, +28 volts. Some OCXOs will have separate inputs for the oscillator and the oven. Example- an HP OCXO has a +15 regulated input that is switched for the oscillator and a +24 volt input for the oven that is on always. I usually try the same voltage as the oscillator first and watch the current as the oven warms up. If it takes too long to heat up, try a little higher voltage. Some units have a separate ground return for the oscillator and oven so you need to watch that. Good luck and thanks for the report. Regards, Tom ----- Original Message ----- From: "Peter Reilley" <preilley_454@comcast.net> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Friday, October 28, 2016 12:09 PM Subject: Re: [time-nuts] Opening an Isotemp OCXO > The only document that I could find said 12 volt. > > Pete. > > > On 10/28/2016 11:49 AM, Poul-Henning Kamp wrote: >> -------- >> In message <10a3ea7d-37f0-51bc-2470-35645d767bbd@comcast.net>, Peter >> Reilley writes: >> >>> The chip is run off 12 volts so it must be CMOS. >> Or the OCXO is not a 12V model ? >> >> > > _______________________________________________ > 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.