I have emailed Peter separately earlier today. The top side marking of the chip appears to indicate it is a TI 74LS05D.
The datasheet is here: http://www.ti.com/lit/ds/symlink/sn74ls05.pdf If it is indeed a 'HEX Inverter', perhaps another 'channel' can be wired in place to see if it would work without having to find another chip. Also, I, too, was wondering if it was 5 V or if there was a 5 V regulator on the board somewhere. Hope this helps. Joe -----Original Message----- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Miller Sent: Friday, October 28, 2016 4:18 PM To: pe...@reilley.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Opening an Isotemp OCXO Can you see the voltage on the yellow dipped tantalum under the board? I think that is what it is. ----- Original Message ----- From: "Peter Reilley" <preilley_...@comcast.net> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Friday, October 28, 2016 3:28 PM Subject: Re: [time-nuts] Opening an Isotemp OCXO > That seems the most reasonable thing to do. > > Pete > > > On 10/28/2016 3:20 PM, Tom Miller wrote: >> It looks like that is the only device that could be damaged by 12 volts. >> Can you find a replacement and try running at 5 volts? >> >> >> ----- Original Message ----- From: "Peter Reilley" >> <preilley_...@comcast.net> >> To: "Discussion of precise time and frequency measurement" >> <time-nuts@febo.com> >> Sent: Friday, October 28, 2016 3:10 PM >> Subject: Re: [time-nuts] Opening an Isotemp OCXO >> >> >>> 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 <jim...@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. >>>> >>> >>> _______________________________________________ >>> 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. _______________________________________________ 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.
