Hi
Some form of base cooling is needed on all of these surplus telecom Rb’s
to keep them from an early death. A great big heatsink could do it. A small
quiet fan and a small heatsink will do it. A somewhat larger fan and no heatsink
will also do the job. Any fan mount should consider the magnetic field
sensitivity
of the Rb. (Move the fan and watch the frequency …)
Bob
> On Feb 26, 2016, at 6:52 AM, davidh <dho...@gmail.com> wrote:
>
>
>
> Hi All,
>
> I used the TAP225K035SRW, from Mouser, and have the PRS10 running again. In
> the process of pulling it apart I managed to break one of the glass
> thermistors (Mouser replacement from US Sensor, part number 104JG1F). Doh.
>
> Whether it was the lamp temperature change (thermistor) or mechanical
> alignment now being a bit different, the frequency moved by about 300E-12
> (measured by locking to my GPSDO 1PPS and comparing old to new "SF" values).
>
> I've also added a cooling fan so the base plate is now below 40dC. I guess
> that could also affect the frequency.
>
> Cheers,
>
> david
>
>
> On 20/01/2016 4:59 PM, Charles Steinmetz wrote:
>> david wrote:
>>
>>> It's a 2.2uF cap, with a 0.125" lead spacing, and I'm looking for
>>> 125dC temp rating. I wondered if there were other characteristics such
>>> as ESR/ESL I need to keep in mind.
>>
>> You're on the right track. Get the highest temperature rating available
>> (which is probably 125C), buy only caps manufactured by one of the
>> known-good manufacturers, and select from a parts series the
>> manufacturer designates as "high reliability" (or equivalent).
>>
>> If it is a solid tantalum, I like the Vishay 199D Series. The AVX TAP
>> Series and the Kemet "T" Series ("UltraDip II") are also high quality.
>> (This list isn't exhaustive -- these are just the ones I've had occasion
>> to qualify.)
>>
>> Best regards,
>>
>> Charles
>>
>>
>
>
> _______________________________________________
> 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.
