[time-nuts] R&S XSRM Rubidium

paul swed paulswedb at gmail.com
Sat Jan 22 03:19:34 UTC 2011


Actually there is a paper by Arthur Molenkamp (Spelling wrong) thats quite
detailed and he seems to have done the same thing I am. You do not need the
heater to start the RB lamp.
I have found 2 things this evening on the FRS-c.

The oscillator is intermittent and I might guess its the variable tuning
cap. Boy is that going to be a pain to pull. But bias voltages and xsistor
behavior look good.

Other item
Indeed there is a silver dot about 1-2mm in the Rb lamp capsule. I might
guess this is Magnus's RB that he reheated. I need to peel the glass/mica
cover off and believe the ampule is released from its holder by breaking the
epoxy that holds it.  Really dislike that idea.

Magnus might the mica cover be removed and the capsule heated in place? The
surrounding area seems to be teflon.

But first things first getting the oscillator to work.
Regards
Paul
WB8TSL

On Fri, Jan 21, 2011 at 10:24 AM, Robert Darlington
<rdarlington at gmail.com>wrote:

> I bought one just yesterday on eBay for $58 USD shipped from China to
> replace one I broke. I did some surgery to change the behavior of the lock
> lamp (I wanted it to light when locked, not when unlocked).  A week later I
> went to document what I did for the list members and walked across the
> carpet, then the plastic thing under my chair and reached out and touched
> the LED lead rather than the metal case.  Zap.    I do know better and I do
> take static precautions.  I also focus intensely on what I'm doing and
> forget simple things like "don't grab a bare lead when charged" sometimes.
>
>
> -Bob
>
> On Fri, Jan 21, 2011 at 5:38 AM, Bob Camp <lists at rtty.us> wrote:
>
> > Hi
> >
> > I would not do anything that's not reversible. You may well come across a
> > FRS-C that's got a good lamp and dead electronics.
> >
> > Of course given what telco Rb's cost these days ....
> >
> > Bob
> >
> > On Jan 20, 2011, at 10:47 PM, paul swed wrote:
> >
> > > Well I think bad news.
> > > I have a frs c apart. Unfortunately the rb lamp doesn't even light at
> > all. I
> > > have been getting RF at about 80.5 Mhz though at the moment I am not. I
> > do
> > > not see any residue on the bulb.
> > > On one of the websites I did see that the lamp should run outside of
> the
> > > oven. Granted not correctly but should ignite. I guess my low lamp V
> was
> > > really saying no lamp. So my fear is this really is not recoverable.
> > > I plan to dig into the oscillator tomorrow to see whats up.
> > > Regards
> > > Paul
> > > WB8TSL
> > >
> > >
> > > On Wed, Jan 12, 2011 at 3:09 PM, Bruce Griffiths <
> > bruce.griffiths at xtra.co.nz
> > >> wrote:
> > >
> > >> Magnus Danielson wrote:
> > >>
> > >>> On 12/01/11 18:41, paul swed wrote:
> > >>>
> > >>>> Did you use a large heat gun or the smaller ones for heat shrink.
> > >>>> I might guess the smaller one
> > >>>>
> > >>>
> > >>> I have a smaller one so that was what I used and it was more than
> > >>> sufficient. I will get a large one too, but with some propper effect
> > >>> control.
> > >>>
> > >>> Cheers,
> > >>> Magnus
> > >>>
> > >>> Just wire a dimmer in series with the heater element.
> > >>
> > >> Bruce
> > >>
> > >>
> > >>
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