That's not something I would have expected. Did you have to unsolder the capacitors to clean them up? Ed On 2016-08-18 10:00 AM, time-nuts-request@febo.com wrote: > My old 2.5A was acting up in strange drifty ways. I opened the oven, and found > that all of the white cube shaped ceramic capacitors in the oscillator were covered > with fuzz on the electrode ends. I am guessing that they were growing a great > tin whisker beard. I cleaned it all off, and performance improved greatly. > > -Chuck Harris > > Ed Palmer wrote: >> I picked up a Sulzer 2.5 (not 2.5A or 2.5B or 2.5C) oscillator and 5P power supply.It's working, but the AlDev at low tau is poor. After a few days of operation theAlDev @ 1sec. is only 1e-10. It's not the power supply. I'm running under 'AC fail'conditions with a lab power supply standing in for the batteries. This bypassesalmost everything in the power supply. Eventually, I plan to replace the batterieswith lead-acid and replace the circuit board with an improved circuit. >> >> So, I'll be opening up the oscillator to see what's what. My first 'usual suspect'will be the Ta capacitors, but I'm wondering about all those carbon compositionresistors. Should I be looking at a wholesale replacement with metal film? Maybejust in the oscillator and AVC areas? Are there any other known trouble spots withthese oscillators? >> >> I haven't been able to find any info on the 2.5. The manuals and schematics for the5A and the 2.5B/C are some help, but the 2.5 is very different from the 2.5B/C. Anyinfo would be greatly appreciated. >> >> Thanks, >> >> Ed

Hi Ed, Nope. I just brushed off the growth, and blew the whole assembly down with compressed air. The whiskers were huge! I think they were capacitively coupling with the ground bits, and since their size and number varied in an uncontrolled way, they affected the frequency in an unstable way. These white cube shaped capacitors are something high quality. The white color is a porcelain glaze that protects the capacitor, and the wires seemed to be connected to some sort of sintered silver area on the body. -Chuck Harris Ed Palmer wrote: > That's not something I would have expected. Did you have to unsolder the capacitors > to clean them up? > > Ed > > On 2016-08-18 10:00 AM, time-nuts-request@febo.com wrote: >> My old 2.5A was acting up in strange drifty ways. I opened the oven, and found >> that all of the white cube shaped ceramic capacitors in the oscillator were covered >> with fuzz on the electrode ends. I am guessing that they were growing a great >> tin whisker beard. I cleaned it all off, and performance improved greatly. >> >> -Chuck Harris >>

Chuck I know those capacitors and you are right they were very high quality way back when. Really interesting on the whiskers. I have seen them on other parts. What is it the tin leaching out. I guess the funny thing was that I have seen them before and just brushed them off and continued troubleshooting. Regards Paul WB8TSL On Thu, Aug 18, 2016 at 2:46 PM, Chuck Harris <cfharris@erols.com> wrote: > Hi Ed, > > Nope. I just brushed off the growth, and blew the whole > assembly down with compressed air. The whiskers were > huge! I think they were capacitively coupling with the > ground bits, and since their size and number varied in > an uncontrolled way, they affected the frequency in an > unstable way. > > These white cube shaped capacitors are something high > quality. The white color is a porcelain glaze that protects > the capacitor, and the wires seemed to be connected to > some sort of sintered silver area on the body. > > -Chuck Harris > > Ed Palmer wrote: > > That's not something I would have expected. Did you have to unsolder > the capacitors > > to clean them up? > > > > Ed > > > > On 2016-08-18 10:00 AM, time-nuts-request@febo.com wrote: > >> My old 2.5A was acting up in strange drifty ways. I opened the oven, > and found > >> that all of the white cube shaped ceramic capacitors in the oscillator > were covered > >> with fuzz on the electrode ends. I am guessing that they were growing > a great > >> tin whisker beard. I cleaned it all off, and performance improved > greatly. > >> > >> -Chuck Harris > >> > _______________________________________________ > 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. >