[time-nuts] FRK-L Rubidium

[Garren Davis]

I've let it run for hours and it gets warm. It has a heat sink and it all gets warm. There are two adjustment screws. One under the heat sink and one on the side of the unit. Is one for the vco and the other for the C-field?



On Feb 8, 2013, at 4:53 PM, "jmfranke" <jmfranke at cox.net> wrote:

> How long do you let it run? Does the crystal oscillator oven get warm? If you let it run more than 15 minutes, and the oven gets hot, the next thing to check is the output frequency range as the tuning voltage sweeps. Not having a frequency counter hurts but there are other methods. One is to use WWV on 10 MHz. You should hear the output slowly sweep through WWV, first on one side of zero beat and then through zero beat to the other side. If the beat stays on one side, the VCO needs tweaking to get the sweep somewhat symmetrical about the 10 MHz WWV signal.
>
> John  WA4WDL
>
> --------------------------------------------------
> From: "Garren Davis" <garren.davis at qlogic.com>
> Sent: Friday, February 08, 2013 7:12 PM
> To: <time-nuts at febo.com>
> Subject: [time-nuts] FRK-L Rubidium
>
>>
>> Been lurking on the list for a while and finally started playing with a FRK-L  rubidium frequency standard. I've had
>> this thing for a while and decided to power it up and see what it would do. I do not get a lock. What I see is the
>> lamp voltage at 8.54 volts which I think is good but the xtal control voltage swings from 2 volts to 15 volts and back
>> to 2 volts and keeps cycling like that. I don't have a good frequency counter but I have a 3 Ghz 40 G/sample scope
>> and it shows that the 10 MHz signal is there. I just don't know how accurate it is. Has anyone seen a problem like
>> this? Can anyone point me to a place to start debugging this? I have the schematics and test tools. I am a test
>> engineer so I'm not afraid to poke around in the guts of this thing. Hopefully I can get this thing running. I also
>> have a thunderbolt that I'll get running this weekend. I don't know how deep I'll get into this time-nuts thing but
>> I have this nice scope and a Wavecrest sitting in my garage and I'd like to put them to use. Any help would be appreciated.
>>
>> Garren
>>
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