L6 core crumbled

Posted: 2/21/2017 11:50:16 PM
Rufuss Sewell

Joined: 2/21/2017


I recently bought 2 Moog Etherwaves. A standard and a Plus. The standard works great but the Plus is wildly out of calibration. 

The manual says it ships with a plastic trimmer tool, but neither of mine came with the tool. So I used a regular metal hex wrench. The tool fit perfectly, but with one slight turn the core crumbled. 

Now the calibration is even worse and the L6 core is a pile of powder like it was made with pencil lead. 

Any clues how to get my plus repaired and calibrated?

Posted: 2/25/2017 12:45:53 PM

From: Colmar, France

Joined: 12/31/2007

There are reasons why the graphite cores should only be touched by special plastic or ceramic tools... One of the first lessons which young radio and tv techs have to learn.

Now, since the graphite core is broken, the plastic thread around is also affected. Thus the only serious way to fix that is by replacing L6. The needed spare part is from Coilcraft, and its denomination is SLOT Ten 5-10 (47uH)

Posted: 2/25/2017 7:32:40 PM

From: Russia, Saint-Petersburg

Joined: 6/6/2016


Yes, this inductor needs to be replaced with a new one. It can be found on this website: http://www.coilcraft.com/forms/files/en/forms/sample_cart.cfm?action=request_sample&part_number=SLOT%20TEN-5-10&CFID=32068471&CFTOKEN=78f1e88c6cfd2e2d-A62D34EA-1016-FC16-794A905B47B266F1&jsessionid=843063a7e701c7d886b14f1b963621430691#
Posted: 2/26/2017 10:50:24 AM

From: Russia, Saint-Petersburg

Joined: 6/6/2016

A little "WRONG" repair technology... :)

Many owners of theremin have problems with broken cores of inductors. In some cases, you can fix the damage without replacing parts. To do this, remove the small crumbs of ferrite, if they are, find the small screw that changes the frequency of the oscillator when it is inserted into the body of the inductor, cut out a small square of plastic in the body size of the inductor and to drill a Central hole in which you need to tighten the screw. Superglue to glue the square to the body of the inductor, and then twist the screw. It's the "wrong" technology and You can argue with it, but sometimes this method can cure the oscillator without replacement of parts.

P.S. If the picture is not seen in the message - it can be viewed in the media album of this site.

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