[time-nuts] Fwd: HP10811 Oscillator Thermal Fuse

Donald E. Pauly trojancowboy at gmail.com
Wed May 10 17:34:28 EDT 2017


The poster at http://www.simonsdialogs.com/2016/09/a-thermal-fuse-and-hp-10811-60111-repair/
reported that the thermal fuse saved an oscillator from destruction
when a thermistor opened.  HP made thousands of these which sold for
$800.  If a large portion failed it would have been addressed.  They
raised the temperature of the thermal fuse to reduce nuisance blows.
I say that nuisance blows equal to real blows are worth the trouble.
You may be getting oscillators on the surplus market or eBay which
have a higher proportion of nuisance blows.


From: Mike Feher <mfeher at eozinc.com>
Date: Tue, May 9, 2017 at 9:10 PM
Subject: Re: [time-nuts] Fwd:  HP10811 Oscillator Thermal Fuse
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>

Respectfully I disagree. I have totally shorted out numerous
oscillator’s fuses with no problems. The design of those thermal fuses
makes them vulnerable to opening just due to years of use without
problem, in any of the electronics. My shorted out oscillators still
work. Ideally, if handy, it is easy enough to replace them if one is
available. They just plug in. If there is a thermal runaway, that
caused the opening, to me that implies that there are other issues.
Regards – Mike

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell, NJ, 07731


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