On 10/28/2016 9:09 AM, Peter Reilley wrote: > The only document that I could find said 12 volt. > > Pete. The 82 series came in a lot of flavors. I have one 82-49 which is definitely 12V ( draws 0.12A when warm and maybe 0.3 when cold) and has a 5V pp square wave output at 10 MHz. It also has a Vref output and an EFC input. What is odd about this one is that it came to me from a TRW swap meet scrap dealer who bought stuff from Cubic Communications in San Diego and it had a "Reject" tag from them. Probably because it was supposed to be a 5 MHz unit as marked, so presumably had the wrong crystal fitted by Isotemp. Other versions of the 82 series (-10) were fitted to Racal Receivers like the RA6790/GM. Screw adjustment on the side and 5 MHz output. Are you sure yours shouldn't have a 5V supply on that output IC? Could be why it died if there is an internal regulator that failed putting the full supply voltage on the IC? Dan

Here is the TI document on "Case Marking." It may not be a 74S30. http://www.ti.com/lit/an/snoa039c/snoa039c.pdf --- Graham == On Fri, Oct 28, 2016 at 11:27 AM, Adrian Godwin <artgodwin@gmail.com> wrote: > 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. > > > _______________________________________________ > 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. >

On 10/28/16 8:31 AM, Peter Reilley wrote: > 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. > could it be some sort of 74C series? if it's intended to run off 12V, a lot of the CMOS parts can run at almost any Vdd (a virtue of 4000 series CMOS - 15V power, no problem) Maybe they got a good price on the 8 input NAND parts? If unused pins are tied high, it's unlikely that they are outputs - most parts are either a totem pole or open collector output, neither one of which would like being tied high.

On 10/28/16 9:13 AM, Scott Stobbe wrote: > 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. > There you go..the design could use a 74S30 as a driver - it's fast, fairly good drive, but runs off 5V. If the regulator is shorted, and you put 12V on it, it will cook.

I confirmed the pin out matches a 74s30 also. An S30 is TTL. Great pix to look at. So 12 V on a 5 V chip is indeed a smoker. Find out why there was 12 V. OK crazy talk I see a 1K resistor next to the VCC chip. Would anyone be crazy enough to use a dropping resistor from 12 V to get 5?? Really bad engineering and I don't actually believe they would. But if true a open 74s30 would indeed show 12 V on pin 14. Good luck. Paul WB8TSL On Fri, Oct 28, 2016 at 12:48 PM, jimlux <jimlux@earthlink.net> wrote: > On 10/28/16 9:13 AM, Scott Stobbe wrote: > >> 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. >> >> There you go..the design could use a 74S30 as a driver - it's fast, > fairly good drive, but runs off 5V. If the regulator is shorted, and you > put 12V on it, it will cook. > > > _______________________________________________ > 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. >

Could also be a quirk about the 74S30 that gives it better phase noise over a basic buffer. On Friday, 28 October 2016, jimlux <jimlux@earthlink.net> wrote: > On 10/28/16 9:13 AM, Scott Stobbe wrote: > >> 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. >> >> There you go..the design could use a 74S30 as a driver - it's fast, > fairly good drive, but runs off 5V. If the regulator is shorted, and you > put 12V on it, it will cook. > > _______________________________________________ > 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. >

The 1k resistor doesn't seem to feed the 'S30'. It looks as though pin 14 (Vcc) goes via that thick track to the +12 input. On Fri, Oct 28, 2016 at 5:46 PM, jimlux <jimlux@earthlink.net> wrote: > On 10/28/16 8:31 AM, Peter Reilley wrote: > > 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. >> >> > could it be some sort of 74C series? if it's intended to run off 12V, a > lot of the CMOS parts can run at almost any Vdd (a virtue of 4000 series > CMOS - 15V power, no problem) > > Maybe they got a good price on the 8 input NAND parts? > > If unused pins are tied high, it's unlikely that they are outputs - most > parts are either a totem pole or open collector output, neither one of > which would like being tied high. > > > > > _______________________________________________ > 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 wounder if originally the designer was hoping to use all 8 wire or'd inputs to lower the input referred noise during midscale transition. Then backed out later for some reason. On Fri, Oct 28, 2016 at 1:03 PM, Scott Stobbe <scott.j.stobbe@gmail.com> wrote: > Could also be a quirk about the 74S30 that gives it better phase noise > over a basic buffer. > > > On Friday, 28 October 2016, jimlux <jimlux@earthlink.net> wrote: > >> On 10/28/16 9:13 AM, Scott Stobbe wrote: >> >>> 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. >>> >>> There you go..the design could use a 74S30 as a driver - it's fast, >> fairly good drive, but runs off 5V. If the regulator is shorted, and you >> put 12V on it, it will cook. >> >> _______________________________________________ >> 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. >> >

There is no regulator chip in the unit. I am thinking that this must be a 5 volt unit. Pete. On 10/28/2016 12:42 PM, Dan Rae wrote: > On 10/28/2016 9:09 AM, Peter Reilley wrote: >> The only document that I could find said 12 volt. >> >> Pete. > The 82 series came in a lot of flavors. I have one 82-49 which is > definitely 12V ( draws 0.12A when warm and maybe 0.3 when cold) and > has a 5V pp square wave output at 10 MHz. It also has a Vref output > and an EFC input. What is odd about this one is that it came to me > from a TRW swap meet scrap dealer who bought stuff from Cubic > Communications in San Diego and it had a "Reject" tag from them. > Probably because it was supposed to be a 5 MHz unit as marked, so > presumably had the wrong crystal fitted by Isotemp. Other versions of > the 82 series (-10) were fitted to Racal Receivers like the > RA6790/GM. Screw adjustment on the side and 5 MHz output. > > Are you sure yours shouldn't have a 5V supply on that output IC? Could > be why it died if there is an internal regulator that failed putting > the full supply voltage on the IC? > > Dan > > >

The reason that there was 12 volts on the unit was because I put it there. I should have tried 5 volts first but the only datasheet that I could find said 12 volts. All the eBay units that look the same say 12 volts. Pete. On 10/28/2016 12:53 PM, paul swed wrote: > I confirmed the pin out matches a 74s30 also. An S30 is TTL. Great pix to > look at. > So 12 V on a 5 V chip is indeed a smoker. Find out why there was 12 V. > OK crazy talk I see a 1K resistor next to the VCC chip. Would anyone be > crazy enough to use a dropping resistor from 12 V to get 5?? Really bad > engineering and I don't actually believe they would. But if true a open > 74s30 would indeed show 12 V on pin 14. > Good luck. > Paul > WB8TSL > > On Fri, Oct 28, 2016 at 12:48 PM, jimlux <jimlux@earthlink.net> wrote: > >> On 10/28/16 9:13 AM, Scott Stobbe wrote: >> >>> 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. >>> >>> There you go..the design could use a 74S30 as a driver - it's fast, >> fairly good drive, but runs off 5V. If the regulator is shorted, and you >> put 12V on it, it will cook. >> >> >> _______________________________________________ >> 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. >> > _______________________________________________ > 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. >