Hi All, Thanks very much for your interesting replies.
I'm beginning to think I'm not letting it settle between adjustments. And besides, The thing has been powered off for at least a decade I would suspect and maybe I'm just watching the crystal adjust to micro changes in temperature as it warms up. It's been on for about 10 days with only about 30 min off time in between. I shall leave it on the bench for a month or two before changing anything again. Now my next question is to those with double oven experience. The service manual says the oven is "not field repairable". And there is minimal description on how to get the oven settings right. The container has 61.3 C on the side - obviously the point of inflection for the temperature curve of the crystal. There are two test points which connect to either side of a thermistor buried deep inside the inner oven. The label next to it say 432 ohms. The resistance it should be at the correct temperature. I'm currently running at 422 ohms (hotter) - that's the temperature that causes minimal drift in frequency (at the moment - maybe this will change after further burning in). The outer oven has no such thermistor. How do I know that is set correctly? If it is too high, I'd assume it would heat the inner oven too much and not allow you to drop the temperature in the inner oven. If it is too low I'd guess the inner heater would have to use more power and do more work to keep it ok. What is the ideal outer oven temperature and how is this worked out? In all this, keep in mind my power rails are running a few volts high and I'm not sure the effect this is having in the oven. Regards, Jim Palfreyman _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
