[time-nuts] FTS Datum 1000A-100

Bruce Griffiths bruce.griffiths at xtra.co.nz
Fri Jan 16 06:20:17 EST 2009

Another factor to bear in mind is that some of these older OCXOs used
insulating foams that are chemically unstable.
With age these revert to a sticky mess which should be replaced in any
case, to ensure that the thermal insulation is increased to the design
Thus it can be useful to at least partially disassemble such OCXOs to
check for such problems.

A lot of the early conductive foams are similarly unstable and breakdown
over the decades.

However there are a few OCXOs that use beryllium oxide within them,
these are usually labelled as such and no attempt at reverse engineering
should be made.
I have one of these lying around.
Safe disposal of such devices is also problematic.


David C. Partridge wrote:
> I think Mark was being ironic - i.e. he agrees with you.
> D. 
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Magnus Danielson
> Sent: 16 January 2009 09:05
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] FTS Datum 1000A-100
> Mark Sims skrev:
>> Ahhh, yes...  as the Great One once said:  If it jams,  force it.   If it
> breaks,  it needed fixing anyway...
> So my first attempt should be to apply 230 VAC directly, since if it fails
> it needs fixing anyway...
> Sorry. Broken logic. Try again.
> This is one of the fields which that kind of reasoning DOES NOT APPLY. 
> Overvoltage and overcurrent is things you need to know the limits for not to
> cause a mess.
> There are other things in which the logic may apply, but again, this is not
> one of those. When having a component in your hand, the same kind of range
> of allowed voltages etc. is not expected since it is expected that the box
> that they go into will handle that as a complete design. If every component
> would have huge overvoltage protection schemes they would be bulky and
> overpriced.
> Besides, I have been fairly successful at opening up things and reverse them
> to the level that I know what levels I can use.
> Cheers,
> Magnus
>> ------
>>>> Or you could just connect the 24V supply and see if you get the 
>>>> clock out, and vice versa. This is certainly a lot easier and less 
>>>> destructive than taking the thing apart to find out which supply is 
>>>> which surely.

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