[time-nuts] Lady Heather numbers

Rex rexa at sonic.net
Tue Mar 12 19:35:28 EDT 2013

Do you think that the oven is working correctly? Is the DC current high 
on power-up then dropping to a steady lower value after warm-up time?

My concern is that the resistors may have unsoldered themselves because 
the oven ran away into an over-temp condition.

On 3/12/2013 9:55 AM, Garren Davis wrote:
> Bob,
> Took your advice and ordered another OCXO. While waiting for it I decided to cut open the
> OCXO with a bad heater that came with the thunderbolt. I found the 1 ohm resistor from the
> 12 volt pin to the heater circuit popped off its solder pads and was laying between the
> insulation and the metal enclosure. While unsoldering the circuit board to fix this the
> 1 ohm resistor in the oscillator circuit popped off its solder pads. For others that have
> OCXO's that don't work this is an easy fix. They are large surface mount resistors and easy
> to solder. Anyways I put the circuit board back in the metal enclosure but did not seal
> it. I put the OCXO back in my double oven and started a run. The enclosed picture is a 72
> hour display. Even though the DAC was still increasing it looked like the PPS had stabilized
> so I did an auto calibrate. You can see this at marker 1. That was almost two days ago.
> Questions:
> 1. Is it normal to take this long for the PPS to stabilize?
> 2. Is it normal for the DAC to keep increasing after two days?
> 3. In general what numbers would be considered good for the PPS and OSC?
> Thanks.
> Garren

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