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Has anyone had a mercotac short out in the swivel part?
Does laying the contact on its side have any effect on it?
What are any other issues?
Does laying the contact on its side have any effect on it?
What are any other issues?
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They go bad of course. They can be mounted horizontally or vertically. The usual problem is bad connections internally which result in the sound cutting out intermittently or all together. It's best to replace it as new one's are still available.
Geo -
Ok
thank you for your reply
Would storing the roto sonic assembly upside down have any effect on it?
The one that I have is shorted.
Mercotac.com web site says that it must kept upright with the arrow pointed up.
Thank you for your input.
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Mercotac is so-named because is uses mercury, or they used to.
The spinning concentric contacts make contact through a layer of mercury which, as we all know, is a liquid metal. It's used in LOTS of applications exactly for this including industrial contacts.
When the mercury seeps out - which can happen over time - the layers lose contact.
This is also why there is an upright condition. Sure they'll work on their side.... for awhile. Even upside down.... for a shorter while.
Did you know very hot mercury can be evaporated and condensed? Fun fact.
At the risk of giving members on the list the all-over-fidgets, you can, in fact, refresh this mercury by soaking it in mercury, again upright. Doesn't always work, but has been known to. Of course, that's a lot of expertise and safety gear not everyone has. Oh, and a lot of mercury not everyone has, either.
They're still for sale. Not every model, but something at least something serviceable might be available. That's probably your very best bet.
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I've never heard of mercury seeping out. What does happen is if a mercotac sits up unused for a long time, the internal contact area that is exposed (not covered with mercury) can tarnish. This is why a mercotac can have a repeating static or no sound condition as it turns. BTW Gulbransen installed them horizontally.
GeoComment
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Ok thank you
the one I have was stored upside down on the rotosonic drum
When I went to test the speaker with a tone generator no sound
Further inspection confirmed the mercotac was shorted.
the speaker works fine.
Just ordered a new mercotac 205 from radwell international with a new cap, kinda pricey, but in the end considerably cheaper than elsewhere.
The franken Leslie 600 rotosonic project is going well, the cabinet is almost completed.
I will post some pictures of it when refinishing is done and the components are installed.
Thanks again
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Ok thank you
good to know
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