[time-nuts] 10MHz Rubidium reference source for frequency counter

Karen Tadevosyan ra3apw at mail.ru
Fri Oct 31 14:23:04 EDT 2014


Alex,
Thank you for the advice. 
I have a colleague in Moscow who has a big experience with MV89A repair.
73 de Karen, ra3apw


> Date: Wed, 29 Oct 2014 14:57:17 -0700
> From: Alexander Pummer <alexpcs at ieee.org>
> 
> Don't give up Karen, the Morion oxcos are relative easy to repair, you need
> one coca-cola can, cut it is pieces until you get a very thin ALU foil, get some
> thicker carton wind around the box of the OXCO's box that way you have a
> heat isolation between the OXCO's box and the vise, which you need to hold
> it, but hold the OXCO that way, that the bottom part where the soldering is
> fare away from the vise, and the can is upside down, "fire up" a relative large
> [ min. 100W] solder iron, if it has temperature setting set to the maximum
> and if it is hot push it hard against  the OXCO can, as soon as the solder
> melted push a piece Alu foil into the gap [ there is a gap between the bottom
> of the can and the rst of the can ] and move to the next part to melt the
> solder. You need to push in at least 5mm long the Alu foil into the gap, if you
> get it all around, you could pull out the content of the OXCO can.
> That is a double oven oscillator, depend what is the problem , you may have
> to open the internal can also, usually it is "visible" if something is broken, just
> power up and follow the current paths, with meter and scope probe, it is
> practical to temporarily disconnect the oven heating [ the large heater
> transistor ].
> I fixed five of them, you need some patience and luck and you have to be
> very careful.
> 73
> KJ6UHN
> Alex




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