I have seen people selling Russian Military SRD's on eBay before. I have not checked lately. Search SRD or step recovery diode. Norman Eric Haskell KC4YOE Keller, TX USA ________________________________ From: time-nuts <time-nuts-bounces@febo.com> on behalf of time-nuts-request@febo.com <time-nuts-request@febo.com> Sent: Tuesday, December 26, 2017 11:00 AM To: time-nuts@febo.com Subject: time-nuts Digest, Vol 161, Issue 38 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... or, via email, send a message with subject or body 'help' to time-nuts-request@febo.com You can reach the person managing the list at time-nuts-owner@febo.com When replying, please edit your Subject line so it is more specific than "Re: Contents of time-nuts digest..." Today's Topics: 1. question about HP 5601a harmonic generator (cdelect@juno.com) 2. Re: question about HP 5601a harmonic generator (Morris Odell) ---------------------------------------------------------------------- Message: 1 Date: Mon, 25 Dec 2017 10:53:24 -0800 From: <cdelect@juno.com> To: time-nuts@febo.com Subject: [time-nuts] question about HP 5601a harmonic generator Message-ID: <AABPECUL4AFTP5PA@smtpout03.dca.untd.com> Content-Type: text/plain; charset=us-ascii When working on the A4 assy. the ONLY adjustments you should make are: - Cavity frequency, unscrew locking ring and while looking at the A7 J1 signal or 2nd harmonic reading adjust for max and then lock down. - Attenuator, Unlock with allen, adjust for same, usually pulled all the way out. Remember to lock. -S5 the one by the attenuator, only needed if tube swapped but if you adjust make sure the peak does not slip when you tighten the locknut. - the top pot, adjust for the same. - If you adjust any of the other locknutted plungers you will NEVER get back to where you need to be!!!! Cheers, Corby ------------------------------ Message: 2 Date: Tue, 26 Dec 2017 11:14:20 +1100 From: "Morris Odell" <vilgotch@bigpond.net.au> To: <time-nuts@febo.com> Subject: Re: [time-nuts] question about HP 5601a harmonic generator Message-ID: <000301d37dde$7a2604c0$6e720e40$@bigpond.net.au> Content-Type: text/plain; charset="utf-8" Hi, Fortunately I have not had this problem but I did have to deal with a destroyed SRD in a HP 5110A synthesizer driver a few years ago. The SRD in that device is maintained at an elevated temperature in a little oven and as a result of a thermostat failure it was reduced to a charred blob. With no possibility of finding an original replacement I set the harmonic generator module up on the bench ( no easy feat!) and tried a range of different diodes to see if any of them would work. After a lot of experimentation I finally hit on a power varactor diode that was the final frequency multiplier in a junked cellphone transmitter from the original analog FM system that was eventually replaced with the current digital one. That diode was made by National Panasonic and is a gold plated stud mounted device. I had to fiddle around to fit it in but the 5110A has not missed a beat since. Of course, in the 5110A it does operate at a much lower frequency than the 5061A, but it's original use was i n the upper VHF range I think. If you can't find a replacement you might have to resort to similar experimentation . Morris > May I know if anyone knows the part number or the specification of the > step recovery diode in the harmonic generator for the old HP 5601A > cesium frequency standard? > --- This email has been checked for viruses by AVG. http://www.avg.com AVG 2017 | FREE Antivirus & TuneUp for PC, Mac, Android<http://www.avg.com/> www.avg.com Download FREE antivirus and malware protection. Tune up your PC, Mac and Android devices for peak performance. Surf safely and privately, wherever you are. ------------------------------ Subject: Digest Footer _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... ------------------------------ End of time-nuts Digest, Vol 161, Issue 38 ******************************************