[time-nuts] Questions about HP 5370B
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.
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