Edgardo,
On 06/30/2012 08:27 AM, Edgardo Molina wrote:
Dear Group,
Good morning. I wish you well. This is my first post to the Time-Nuts
group. Please be gentle with the newbie ;)
I have been offered an HP 5065a Rubidium Frequency Standard recently in
what I feel, a bad operational condition. I need a reliable rubidium
standard for my time/frequency experiments, still I am in doubt to
invest in buying such and old beast. The general situation of the
instrument (for what I have been able to see from the first inspection) is:
5Mhz output: Working. sine wave clean but a little bit distorted when
ramping up. A couple of frequency counters showing 5.0000014 Mhz in
frequency. No transient pulses or other glitches around the output
signal. Last digits vary sporadically.
I would guess that you need to trim it so it locks up. Not all that hard.
No lights coming up when the instrument turned on. No physical damage of
abuse on case or internal components. No options installed . A couple of
electrolytic caps replaced on some boards, no trace of burnt PCB traces
or visible damage to electronic components or physics package. Haven't
got the manual until today and was unable to check on the front panel
voltages to check on general health. As turning the voltage test
selector knob, voltage is shown for most positions, except of course
battery and the 100 Khz oscillator output. Some voltage test positions
get the instrument needle to go full scale and out of range, other
appear to be within scale.
I would assume that the 2nd harmonic is essentially zero, as frequency
is off, assuming you had a good reference.
I can perform a second visual and operational inspection today, this
time with a copy of the instrument manual. I will take my own trusted
frequency counter and portable digital storage oscilloscope. Would
really appreciate if I could receive comments from you experts to
evaluate if such a unit could be worth buying. The asking price is $1K
USD. Should I consider it an instrument that can be repaired and
serviced to show some decent performance? Or should I look somewhere
else to get a decent rubidium frequency standard.
Thank you beforehand for all your kind and expert comments.
I think it is a bit high asking-price for the state it is in, but these
are quite serviceable and it may take some trimming for them to lock up.
It's all in the manual. The operation light on one of mine never turns
on, since the lamp has burned out. This is normal maintenance one should
expect.
You rarely use 100 kHz today anyway, the only time I use it is to check
that it works.
cheers,
Magnus
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