[time-nuts] HP 5065A questions

[Joe D'Elia]

Whilst mainly a voltnut I have often turned to this forum for answers on the
telecom sourced rubidium oscillators and have two units that I use for
keeping my counters honest. However recently I was browsing in the
scrap/redundant shelves at a local calibration lab and came across an
HP5065A carcass, no top and bottom cover, the right front handle had been
sheared off, the chassis by the transformers was buckled and the lid of the
physics package was also buckled and had a quarter inch gap around a third
of the circumference. However it had a very nice HP10811 oscillator and the
size of the physics package made it very tempting for a teardown. So I duly
paid the £20 they wanted and took it home with no expectations that it
worked. On powering it on there were signs of activity on the Circuit check
meter so I left it for an hour and then went through the startup process and
the lock light came on! Now I'm in a quandary as I hadn't intended to add it
to my stock but I can't let such a beautiful piece of engineering be
cannibalized. So to the point of this missive

How do you tell the state of the Rubidium lamp in the 5065A? there is no
mention of ageing in the manual and I'd like to know there is some life in
the unit. It's a late 88 build and has spent the past twelve or so years
since it's accident on a shelf.

Secondly since I turned it on it's gone from being 3 millihertz below
nominal to +24 millihertz. That's over six days and the rate of change is
slowing down so I'm going to let it run until it's stable and then try the
adjustment procedure. Before I do that should I try mending the Physics
package lid so that it's sealed, could that be the cause of the drift?

I look forward to your responses as I set out on this unintended journey.

JoeD