[time-nuts] Re: DOXCO from Z3801

[DM]

Andy,
Here's a link to a description of the outer oven and its controller on the KO4BB manuals site.

http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=02_GPS_Timing/Z3801/Z3801A_Outer_Oven/Web_Page.

However, on the link to the document containing the text, all of the images have gotten lost and are not visible.
Fortunately, I had downloaded the complete page and all the files, and put them all into a PDF for my own reference.  I've attached it to this message.  It contains an in-depth description of the outer oven and its controller circuitry, and I think it contains all the information you're after.

Enjoy!
DaveM

----- Original Message -----
From: "Time-Nuts" <time-nuts at lists.febo.com>
To: "Time-Nuts" <time-nuts at lists.febo.com>
Cc: "Andy Talbot" <andy.g4jnt at gmail.com>
Sent: Wednesday, December 7, 2022 3:38:54 AM
Subject: [time-nuts] Re: DOXCO from Z3801

> I've been given a defunct Z3801 with a fully working ovened oscillator.
> The rest of the GPSDO circuitry is just junk and will be chucked, but I
> want to get the DOXCO running as a backup high stability reference here.
>
> I've worked out the power connections for the oscillator and inner oven,
> and have powered it up with +12V & +24V supplies.   It's currently just
> warmed up and is happily generating a nice sine at 10MHz, with +0.3V (at
> the moment) t on the EFC.
>
> I applied 24V to the outer oven earlier to see what happened, and measured
> the thermistor resistance as it warmed, watching it fall from 110kΩat room
> temp to 30kΩ where I stopped.  I know the controller for the outer oven is
> in external circuitry, but a brief web search failed to show a) what
> temperature it should run at, To, and b) what the thermistor resistance
> would be at that temperature, Ro.
>
> Does anyone here know these figures off hand, or do I need to go to the
> web and download the circuit and trace out the outer oven controller
> details.   I'll be doing my own controller circuitry, so just need To and
> Ro.
>
> Andy
> www.g4jnt.com
>
>
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