[time-nuts] FRSc RB lamp experiment

[paul swed]

By the way I can disconnect pin 1 on the lamp assembly because I made a 5"
jumper assembly so that the area can be easily worked on.

On Sat, Feb 12, 2011 at 10:27 PM, paul swed <paulswedb at gmail.com> wrote:

> Well pretty good news
> The lamp voltage went from 1.83 volts a dead bulb to* 8.9 volts a new bulb
> *.
> By adjusting the oscillator I can get to 9.6 volts but I know the the
> oscillator will not start correctly at 82 Mhz its happy at 92 Mhz.
> Its not locking but that can be due to several issues.
> At least 3 grounds are not connected. These are completed by the boards
> being mounted on the oven.
> The +24 lamp ignition is hanging at +17. So again the grounds or I have a
> problem in the lamp regulator. I suspect its the grounds actually. I
> disconnected pin 1 into the oven and applied 24 volts when the lamp ignited
> manually backed it down to 17volts.
> So tomorrow will start to reassemble the boards for correct grounding.
> Regards
> Paul.
>
>
> On Sat, Feb 12, 2011 at 7:57 PM, Magnus Danielson <
> magnus at rubidium.dyndns.org> wrote:
>
>> Dear Paul,
>>
>>
>> On 13/02/11 00:02, paul swed wrote:
>>
>>> Well indeed Magnus the black stuff and silver blob were rb.
>>> 300 degrees F for 15 minutes made it all go away.
>>> I was using a j thermocouple to measure the temp and right at the bulb.
>>> The trick seems to be for a FRS c to get the blob to the lowest point of
>>> the
>>> capsule thats observable. I did this with the normal RB power system
>>> heated
>>> to 177 degrees. Gently tapped a few times to get it concentrated.
>>> Then powered off and let it cool.
>>> Next step hung the assembly from a lamp so the heat gun could be pointed
>>> straight up to boil the RB off at 300 degrees for 10 minutes and let it
>>> go
>>> for 5 more for good luck.
>>> The dark area on the capsule is significantly reduced and no trace of the
>>> silver blob.
>>>
>>
>> I had mine go greyish on the first heat-up, but then I cleared it on the
>> second run.
>>
>>
>>  During the heating I could actually see the silver blob shrink.
>>> The RB lamp lights well and looks good.
>>> Now to try reassembling everything. That will be a job.
>>>
>>
>> Good news!
>>
>> Eager to hear of lock-up results!
>>
>> It seems like the normal temperature of the bulb is good for keeping it
>> lit, but you need to go further up for the clean-up operation. Maybe this is
>> why the grey rubidium-coating didn't rub off for others... they didn't go
>> high enough. Still, no extreme temperatures is needed to get the job done.
>>
>>
>> Cheers,
>> Magnus
>>
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>
>