[time-nuts] Z3801 EFC error

EWKehren at aol.com EWKehren at aol.com
Tue Nov 1 09:37:07 EDT 2011


If any one needs an original 10811 manual I have a few. Please contact me  
off list.
Bert
 
 
In a message dated 11/1/2011 9:21:43 A.M. Eastern Daylight Time,  
jltran at att.net writes:

Bob,

The thermal fuse is inside the OCXO which is inside the  outer oven.  There
was a recent (past week or so) thread on this list  about a thermal fuse
failure including pictures of the inside where the  fuse is located.  This,
however, was for the 'non' wrapped version of  the 10811.  The problem will
be getting past the outer oven.   I've never tried that though I have
replaced the thermal fuse on the 'non'  wrapped 10811.  That was really
straight forward.

I don't  recall seeing a manual specifically for the 'wrapped' version of 
the
10811  but the manual for the 'non' wrapped version is available on  the
internet.  I think one is on Didier's site.

The trouble  shooting guide is very helpful in finding out if the thermal
fuse is the  problem.  Just measure the heater circuit current for the  
inner
oven.  If zero, the thermal fuse is the place to start.   The outer oven,
though, I think is separate.  If your Z3801A is used  indoors, I suspect the
outer oven is probably not needed.

Good  luck.

Joe


-----Original Message-----
From:  time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of  Robert Benward
Sent: Tuesday, November 01, 2011 8:00 AM
To: Discussion  of precise time and frequency measurement
Subject: Re: [time-nuts] Z3801  EFC error

Joe,
Good guess.  It's a 10811 with an additional  oven wrapped around it for 
better thermal control.  I'll check it in  a couple days when I get home.  
Is

this thermal fuse on the  outside?

Anyone have a schematic of this unit?

Bob

-----  Original Message ----- 
From: "J. L. Trantham"  <jltran at att.net>
To: "'Discussion of precise time and frequency  measurement'" 
<time-nuts at febo.com>
Sent: Tuesday, November 01,  2011 12:21 AM
Subject: Re: [time-nuts] Z3801 EFC error


>I  think it uses a 10811 OCXO.  See if it is warm.  If not, perhaps  the
> 'thermal fuse'?
>
> Joe
>
> -----Original  Message-----
> From: time-nuts-bounces at febo.com  [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Bob
> Sent:  Monday, October 31, 2011 11:17 PM
> To: time-nuts at febo.com
>  Subject: [time-nuts] Z3801 EFC error
>
> Hi,
> My Z3801 just  crapped out.  It seems that the DAC has ramped up to the
> rails,  1048560, and I'm getting an EFC fault.  Any tips before I open  
the
> unit and start poking around?  The oscillator is running and  pretty 
close 
> to
> 10MHz, I don't have any reference accurate  enough to check it.  Any 
trends
> here, is it the EFC in the  oscillator or is it the DAC and following
> amplifiers?
>
>  Thanks, Bob
> _______________________________________________
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>
>
>  


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