Hi Folks, i own a Efratom FRK-L which started into making trouble since the last time i switched it on. I monitor the "lamp voltage" as well as the VCXO control voltage. The unit locks a few minutes after power up. But then the VCXO voltage is kind of "noisy" and unstable. While it formerly came to a very stable value with changes only in the microvolt region after some hours of warming up, now the VCXO control voltage jumps around in a 50 mV peak to peak region and sometimes it would even loose lock at all.
The "lamp voltage" is close to 7.00 V and very stable, so i do not expect it to be a physical package failure. When i monitor the output frequency, this seems to be indeed stable up to my counter resolution of 1E-9 @ 1s. From that i induce that the servo electronics in the FRK-L is working ok and that it is indeed trying to correct for some VCXO instabilities. The big question however is: What makes the VCXO which has been working very stable for years go in such a instable behaviour from one day to another? Has anyone of you seen a behaviour like this with a FRK-L? What way should i go for a deeper diagnosis: Oscillator electronics or chrystal heater electronics? Best regards and thanks in advance for any help. Ulrich Bangert [EMAIL PROTECTED] _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
