Hi,

the HP 10544A OCXO driving my HP5328A counter failed due to a blown
thermo fuse. The underlying problem was a broken Thermistor lead
(unfortunately within the sealed hole) which caused the owen to run away
(and blow the fuse). I already searched, but didn't find answers to the
following questions. In order to find a suitable replacement thermistor,
I would like to know:
- At what temperature does the OCXO nominally operate?
- What are the characteristics of the original thermistor used by
HP? (my copy of the 10544 schematic lists the thermistor as
"9.93K @80C 0637-0122", but it is difficult to distinguish "6" and
"8")
- Which temperature specification is required for the thermo fuse?

Thanks in advance!

73 de Arnd

--
Arnd Gronenberg
EMail:
HAM: DJ9PZ / AB2QP