[time-nuts] EFRATOM LPRO-101

[Bob Camp]

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" <jim at commo.com>
> Sent: Tuesday, February 02, 2010 9:08 PM
> To: <time-nuts at 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
>> 
>> 
>> -- 
>> 
>> 
>> 
>> The heart of the wise inclines to the right, but the heart of the fool to the left. Eccl 10:2 (NIV)
>> 
>> 
>> 
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> 
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