One thing I've noticed in old mystery oscillators and other RF modules,
is that they often use 3-terminal or other regulators inside. If you
gradually increase the supply voltage, the current goes up rapidly, then
levels off as sufficient overhead is reached. That gives some idea of
where they were designed to run. Also, there are usually reverse-voltage
protection diodes in series, so if you get no current draw in one
polarity, try the other. Reverse protection may sometimes be implemented
with shunt diodes instead, and it's obvious when it's backwards.
Of course, if it's an OCXO with a single supply, it will take higher
current for warmup, then settle down, so takes longer to figure out
what's going on.
For the other pins, first ohm them out to see if some are extra grounds,
and for any measurable resistance to ground. Once you get it juiced up
and running, check for voltages on the pins - sometimes an internal DC
reference is brought out to supply a tweak pot for the EFC. Good luck.
Ed
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