[time-nuts] SRS PRS10 problem

Bob Camp lists at rtty.us
Wed Feb 16 21:56:49 UTC 2011


Hi

Since the unit is current production, the part should be around. There are a
number of the old Motorola RF parts that are very hard to find. They have
been out of the RF business for quite a while. That should not be one of
them. 

Based on a quick search, M/A-Com seems to make them. $20.95 at RF Parts.
There may be other sources as well. 

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of paul swed
Sent: Wednesday, February 16, 2011 4:31 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] SRS PRS10 problem

Well a couple answers.
If those are RB whiskers try the heat gun at 300 degrees on it for 15
minutes. As Magnus suggests and I just tried for the first time. It actually
worked and I recovered the rb lamp.
I imagine the transistor may be hard to get but its a motorola should be
obtainable.
Good luck
Regards
Paul
WB8TSL

On Wed, Feb 16, 2011 at 4:19 PM, Pete Lancashire
<pete at petelancashire.com>wrote:

> write a letter (real one) to their ceo & pres and if there is a
> engineering VP, only cost you a buck, fifty.
>
> sometimes works
>
> -pete
>
> On Wed, Feb 16, 2011 at 12:11 PM, Brendan Minish
> <ei6iz.brendan at gmail.com> wrote:
> > Right, to follow up on my own email
> >
> > I took it apart
> > The lamp assembly has failed.
> >
> > In the PRS10 the lamp is exited by a strong RF field @ 150Mhz
> > this is generated by an MRF134 within the lamp package
> >
> > The failure mode was caused by the growth of a substantial tin whisker
> > within the lamp assembly which appears to have killed the MRF134.
> >
> > I made contact with SRS about purchasing a replacement lamp assembly but
> > since I bought it on the used market they are not willing sell me a
> > replacement lamp assembly. Frankly I am not terribly impressed with
their
> > response on this.
> >
> > Does anyone on list have a 'donor' PRS10 that might have a good lamp
> > assembly that they would be willing to sell me ?
> > Perhaps someone on list has a commercial relationship with SRS and might
> be
> > able to assist me with purchasing it?
> >
> > Hoping someone can help out, My alternative is to attempt to source an
> > MRF134 and have a go at replacing it but there may be other damage in
> there
> >
> > regards
> > Brendan
> >
> >
> >
> > On 14/02/2011 18:53, Brendan Minish wrote:
> >>
> >> Hello all
> >>
> >> My SRS PRS10 ( http://www.thinksrs.com/products/PRS10.htm ) Rubidum
> >> frequency standard was power cycled a few days ago, since then it has
> >> not achived rubidium lock.
> >> I have tried a full rest and also further power cycles with no joy.
> >>
> >> The SRS RS232 application reports the following parameters that 'look
> >> wrong'
> >> ad3 (lamp drain ) 2.001
> >> sd2 (fet voltage set ) 255
> >>
> >> ad3 at 2 (Lamp drain volatge 20V) would appear to correspond with the
Rb
> >> lamp discharge not beginning
> >>
> >> this unit is of course out of guarantee and came to me via Ebay about 5
> >> years ago, is anyone on list familiar with troubleshooting these units
> >> who Might have some general ideas of how best to proceed with repairing
> >> the unit
> >>
> >>
> >
> >
> > --
> > 73
> > Brendan EI6IZ
> >
> > _______________________________________________
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