[time-nuts] Symmetricom (Datum/Microsemi) CS tubes after storage

Julien Goodwin time-nuts at studio442.com.au
Mon Jun 25 14:52:48 EDT 2018

Thanks for the on & off-list responses folk.

Sadly I didn't have a usable RS232 adapter set when I first powered this
on a month back. It's actually on a desk I'm borrowing in Sunnyvale[1]
(California), hoping to determine if it's worth the significant cost of
shipping it home to Sydney[2].

I don't have a 3kV supply myself, nor do I have a lab where I'd feel
safe messing with that sort of thing (the labs I could borrow around
here are all shared, and 3kV is not something leave where random people
could touch).

I guess I'll leave it for another month or so, hopefully in that time
I'll be able to see if there's an improving trend.

1: Just a few blocks from Stanford Research who, by the way, I'm not
having any luck trying get some replacement feet from, for some kit that
used to be rack mounted.

2: It's much cheaper if I were to pull the tube, since I could then just
take it as luggage on a flight home. But it'd make more sense to have it
dropped off to Microsemi for a tube swap, and have them ship it back to
Australia for me. Either way, that's a chunk of money I'm not sure I
want to pay right now.

On 20/06/18 16:52, paul swed wrote:
> Julien
> Do you see any reduction in the current. It may be slight. If so time is
> your friend. Let it cook.
> If not KE5FX is a time nut also. Here is what he did.
> http://www.ke5fx.com/cs.htm
> Granted you need a 3KV supply and it is hazardous. I am not an expert on
> your tube.
> Others may have better insights.
> Good luck.
> Regards
> Paul.
> On Wed, Jun 20, 2018 at 7:32 PM, Julien Goodwin <time-nuts at studio442.com.au>
> wrote:
>> I recently picked up a used Cs clock (Symmetricom labelled Cs4000).
>> Sadly, it turns out to have been stored for about a year (at least, a
>> year since it was last claimed to lock) and doesn't appear to be locking.
>> I've had it on for about a month now, and ion pump current is still
>> quite high[1].
>> Given the unit is now over 10 years since manufacture, with power on
>> hours of ~5 years I'm guessing this now probably has a dead tube, and
>> unless I want to spring for a new tube I have a paperweight.
>> 1: Monitor3 display for the unit including the alarm window:
>> https://julien.studio442.com.au/images/cs4000_monitor3.png
>> (That's the set that fires after alarms are cleared)
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