[time-nuts] Questions about HP 5370B

Dan Rae danrae at verizon.net
Tue Sep 14 15:28:12 UTC 2010

  On 9/14/2010 1:23 AM, John Miles wrote:
>> As Bruce suggests, you'll want to peek inside to see that you
>> really do have
>> a 10811 oscillator. If so, then it sounds like the thermal fuse
>> (F1, inside
>> the 10811) might be open.
> Just short it out, or if you like, put in an NTE part with a similar temp
> rating.  It serves little or no useful purpose.
> -- john, KE5FX
I hate to disagree with John who knows a heck of lot more than I ever 
will, but in this case it will protect the oven from cooking up if the 
control circuit fails with the heater full on, which can happen.

I did have a 5370B with a 10811 that had a bad thermistor in it as well 
as an open fuse.  I'd guess that's why -hp- fitted it.

  But yes, the thermal fuses can and do fail open for no good reason, 
and it sounds like this has happened here, but I would not recommend 
shorting it out permanently.


More information about the time-nuts mailing list