[time-nuts] EFRATOM LPRO-101

[Jim]

Oops!  I had the wrong subject on the last message.

Jim
Thank you all for your support and suggestions.  I did get in touch with 
Bob and he is sending me another one.  I agree, he is great to deal with.

I popped the cover off the unit and in fact found R215 open.   It is a 
1208 283KOhm itsy bitsy tiny dude, and there are even tinier dudes and 
dudettes on the board.  They must be breeding.  What happened to tube 
sockets and wire wrap?

A local Ham friend has a SMD resistor for me to pick up and will do so 
probably tomorrow before the Super Bowl.  It has been an interesting 
learning curve for me with these devices, mainly learning the size.  
Thanks to Scott of TAPR fame he set me on the right track.

Back to the unit, It starts out at over 10, 000,100, climbs a little 
higher, then cycles around 10.0000, 170.  The logic never goes low.

After I replace the resistor I will report back to the group.

Again, thanks for your support.

Jim Conley N0OBG

The heart of the wise inclines to the right, 
    but the heart of the fool to the left. Eccl 10:2 (NIV)




t
Date: Wed, 3 Feb 2010 12:37:08 -0500
From: "Bob Camp" <li...@cq.nu>
Subject: Re: [time-nuts] EFRATOM LPRO-101
To: "'Discussion of precise time and frequency measurement'"
        <time-nuts@febo.com>
Message-ID: <2e2b89b2fa654d7b86f3a4ec47509...@vectron.com>
Content-Type: text/plain;       charset="iso-8859-1"

Hi

I would second that as well. 

I got an LPRO in that had a "rattle" when it arrived. After some thought, I
popped the can and figured out what the issue was. Since it might have been
gong back, I kept Bob in the loop during the entire process. He was very
supportive through it all. Definitely a first class guy. 

Bob

-----Original Message-----
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Doug Parker
Sent: Wednesday, February 03, 2010 9:23 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] EFRATOM LPRO-101

Hi,
?
I'd like to confirm that Bob is a very good seller and been great with the
things I've had off him. 
?
He's also a member of this group
?
Doug
G4DZU

--- On Wed, 3/2/10, EB4APL <eb4...@cembreros.jazztel.es> wrote:


From: EB4APL <eb4...@cembreros.jazztel.es>
Subject: Re: [time-nuts] EFRATOM LPRO-101
To: "Discussion of precise time and frequency measurement"
<time-nuts@febo.com>
Date: Wednesday, 3 February, 2010, 13:20


Hi,

Bob Mokia is a very good seller and you'll not have problems with him.? 
In? order to avoid paying the return shipping and the delays I would ask 
him to let you open the unit and try to find an obvious fault such a 
loose connection.? When I bought my Rb (from another source) I opened it 
even it was working ok, and I found one of the connector pins touching 
its PCB pad without any trace of solder on it; nevertheless it worked 
perfectly but it was just a question of time before the unit will begin 
to act intermittently so I fixed it.? Thinking about I realized that 
maybe this unit showed problems and it was retired from active service 
and maybe it has very low hours on it.
Do your unit sweeps its frequency above and bellow 10 MHz when warming 
up the first minutes? it is the normal operation before a lock is 
obtained and if it is not done it will never lock the oscillator to the 
Rb frequency.

Good luck,
Ignacio, EB4APL

-----------------------------------------------------------------------
Bob Camp wrote:
  
Hi

A little more data from a group of recent units:

The XTAL pin is looking at the VCXO control voltage, It should move around
    
(sweep) at turn on. It will settle in the vicinity of 6 volts. I have seen
units anywhere from 5.5 to 7.2 volts on this pin.
  
The BITE is a logic level pin, it's either high or low. 

The lamp voltage on "early" units runs around 6 volts. On "later" units
    
it's up around 9 volts. This may be a better bulb, or it just may be a
different photo detector. Every time I've asked about lamp voltage, the
answer has been "in range is ok". Trying to predict life from lamp voltage
apparently is more complex than it might seem.? I would not throw out a 6
volt unit simply because it's not a 9 volt ....
  
Bob


On Feb 3, 2010, at 7:08 AM, Roy Phillips wrote:

???
    
Hi Jim
This would appear to be a faulty unit, I also purchased the same unit
      
from Bob Mokia two weeks ago and its performing very well.? It gives a
frequency of 10.000,000,005 Mhz.
  
One very obvious fault is the BITE voltage - - this should initially be
      
4.5 volts, which falls to less than 30 mV. within a few minutes. The XTAL
Control Volts, after a short while falls to 6.145 V., so yours, at 14.67 V,
would seem to be wrong ! The Lamp volts settle to 6.736 V, and the Ext? C
Field is 2.426 V. , which checks with your result.
  
I'm? sure you will get a replacement.
Roy

--------------------------------------------------
From: "Jim" <j...@commo.com>
Sent: Tuesday, February 02, 2010 9:08 PM
To: <time-nuts@febo.com>
Subject: [time-nuts] EFRATOM LPRO-101

? ???
      
Hello all.

I received an EFRATOM LPRO-101 last week from eBay Fluke 1, and wired it
        
up last night. The results are not good.
  
Using a HP 5370B counter with calibration less than one year old, the
        
frequency reads = 10,000,146,012.9
  
Power Applied = 24.9Vdc @ 0.30 amps after warm up
Lamp Voltage = 5.9 Vdc
Ext C Field = 2.437
XTL V Mon = 14.67
Bite = 4.57

Bite never goes low.

I just sent an email to the outfit I purchased it from, but would like
        
to get this working instead of waiting a month or so.
  
Is it dead?? Any thing I can do to revive it?

Any suggestions?

Thanks to all.

Jim N0OBG


--



        





  

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