Jurg, There is a tantalum capacitor on the lamp board. When it fails it can corrode the board. I have had this happen. You can likely replace the tantalum capacitor and repair the foil connections. An issue with the PRS-10 units is that the factory has implanted settings for the specific unit in its firmware. They do not give customers access to the commands to alter these settings. Swapping boards likely has programmed the wrong bias and operating settings into the lamp driving FET. Bruce, KG6OJI -----Original Message----- From: time-nuts-request <time-nuts-request@febo.com> To: time-nuts <time-nuts@febo.com> Sent: Sun, Feb 22, 2015 9:05 am Subject: time-nuts Digest, Vol 127, Issue 26 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 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. Re: OXCO insulation (Andrea Baldoni) 2. PRS10 Rubidium (Jürg Kögel) ---------------------------------------------------------------------- Message: 1 Date: Sun, 22 Feb 2015 10:44:24 +0100 From: Andrea Baldoni <erm1eaae7@ermione.com> To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Subject: Re: [time-nuts] OXCO insulation Message-ID: <20150222094424.GA31822@sol.ermione.com> Content-Type: text/plain; charset=us-ascii On Sat, Feb 21, 2015 at 06:09:42PM -0600, Dave M wrote: > What kind of foam insulation is generally used inside an OXCO? Do all > manufacturers use the same kind? Is it available in small (hobbyist) > amounts? In the only one kind I opened, Milliren DOCXO, the insulation was air. Best regards, Andrea Baldoni ------------------------------ Message: 2 Date: Sun, 22 Feb 2015 16:44:06 +0100 From: Jürg Kögel <j.koegel5@gmail.com> To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Subject: [time-nuts] PRS10 Rubidium Message-ID: <CALi71odkgaWCpwiesnm5dr21wZ4ZNsSNCPGUinbp1se88Yg-ow@mail.gmail.com> Content-Type: text/plain; charset="utf-8" Fellow time nuts. I have two SRS PRS10 Rb’s that I did purchase 10 years ago. Both have been working for the last nine years. One did fail last year and I finally got around to looking at it in the last two weeks. The attached picture shows the trauma to the lamp board. I do not understand the corrosion since it has been in a very controlled environment in my basement. Since the failed unit does have the 1 pps loop control I moved the processor board to the still working unit. Did not work. Does it take more than just moving that one board to get 1 pps loop control? Second any ideas as to what may have happened to the lamp heater board. Any recommendations? Plan on making a replacement board. Have a power FET MRF134 Thanks Juerg