The 10811-60111 that came in my 5370B counter turned out to have an open
circuit Thermistor in it. This is a non-replaceable part in theory.
However, nothing to lose, I have successfully substituted a Digikey Part
number: 317-1371 100 kOhm 1% Thermistor ( from Cantherm, part number:
Dan Rae wrote:
The 10811-60111 that came in my 5370B counter turned out to have an open
circuit Thermistor in it. This is a non-replaceable part in theory.
However, nothing to lose, I have successfully substituted a Digikey Part
number: 317-1371 100 kOhm 1% Thermistor ( from Cantherm, part
Bruce Griffiths wrote:
Dan
The real reasons that this part is labelled non replaceable are
1) its epoxied to the oven.
2) Setting R20 to the correct value actually requires plotting the OCXO
frequency vs R20 and selecting R20 so that the OCXO frequency is located
at the stationary point
Rick Karlquist wrote:
Bruce Griffiths wrote:
Dan
The real reasons that this part is labelled non replaceable are
1) its epoxied to the oven.
2) Setting R20 to the correct value actually requires plotting the OCXO
frequency vs R20 and selecting R20 so that the OCXO frequency is located
Bruce Griffiths wrote:
Meanwhile, before posting a correction I was trying to find data on the
oven setpoint temperature tolerance.
The relevant HP Journal with an article on the HP10811A is:
http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1981-03.pdf
One concern is:
How accurate does one'
Dan Rae wrote:
Bruce Griffiths wrote:
Meanwhile, before posting a correction I was trying to find data on the
oven setpoint temperature tolerance.
The relevant HP Journal with an article on the HP10811A is:
http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1981-03.pdf
One concern is:
How
Bruce Griffiths wrote:
One concern is:
How accurate does one' thermometer which one uses to calibrate the
thermistor bridge setpoint have to be?
Bruce
The thermistors HP used were quite accurate, so you didn't
need a thermometer. You just calculated the correct resistor
value for the
