Moog Theremini Theremin

Moog Etherwave Theremin comes with a fuse?

Showing Posts 1 - 7 of 7
Posted: 12/16/2012 12:19:00 AM
arehandora
Joined: 12/16/2012

threads posts

Hello there! 

I need some help here!  I made a terrible mistake.... I pluged my Theremin without the 110 to 220v adapter. Now it is not working but I am not sure if it's only the transformer or the hole theremin burned/broken.

Does anybody knows if the Moog Etherwave comes with a fuse?

I am terribly sad and worry...

Thanks for reading 

aleja

Posted: 12/16/2012 6:00:39 AM
Jason
From: Sammamish, Washington
Joined: 2/13/2005

threads posts

I don't believe there's a fuse in the theremin.  I recommend contacting Thierry Frenkel, who is very experienced in repairing theremins.  He could probably figure out what's wrong and replace the necessary parts pretty quickly.

http://theremin.tfrenkel.com/ 

 

Posted: 12/16/2012 7:13:45 AM
FredM
From: Eastleigh, Hampshire, U.K.
Joined: 12/7/2007

threads posts

Dont be too panic stricken!

There is a fuse in the power adaptor, if the schematic I have is right.. But that probably wont have saved anything much, although, with luck, it might have blown and protected the transformer.

The maximum allowed input voltage for the regulators is about 35V - I believe about 18V is the normal maximum input (but I may be wrong) but anyway, from 240V you will have given the regulators more than they could cope with.

You will also probably have put more voltage across the supply electrolytics (C19 and C20) than they can cope with..

A lot will then come down to luck.. Replacing C19, C20, and the 2 regulators (U1 and U2) may be all thats needed.. This will be true IF the regulators failed open-circuit, and if this is the case, its quite a simple and cheap repair.

If one regulator failed open circuit, one short circuit, you will probably be ok with just replacing the regulators and capacitors as described above.

If both failed short-circuit, then damage could be more extensive - the LM13700 (U3) has maximum voltage rating of 35V (or 44V for A rated parts) so if the supply exceeded this, it could die -

I think you would need to be quite unlucky for damage to go beyond the above  - but with this sort of thing it is impossible to absolutely predict what may fail -

I would start by replacing C19 and C20, and replacing U1 with a LM7812 (not a LM78L12) and U2 with a LM7912 (not a LM79L12) .. These beefier regulators will allow one to test for any other failures. If it doesnt work, I would then replace U3.

Fred.

 

Posted: 12/16/2012 1:21:29 PM
Thierry
From: Colmar, France
Joined: 12/31/2007

threads posts

The fuse in the Etherwave's power supply is a thermal fuse which will break when the transformer gets too hot. It is not rapid enough to protect the instrument from over-voltage.

Posted: 12/16/2012 11:32:30 PM
FredM
From: Eastleigh, Hampshire, U.K.
Joined: 12/7/2007

threads posts

"The fuse in the Etherwave's power supply is a thermal fuse which will break when the transformer gets too hot. It is not rapid enough to protect the instrument from over-voltage." - Thierry

Then it is probably the case that this patient needs some of its organs transplanted in Thierry's clinic!

 

Posted: 12/17/2012 8:09:34 AM
Thierry
From: Colmar, France
Joined: 12/31/2007

threads posts

Dr. T. can be asked for details here: 

Posted: 12/18/2012 9:27:13 PM
arehandora
Joined: 12/16/2012

threads posts

Thank you kindly :)
 I forgot to say that I am from the south of the world, aka Argentina! So unfortunately I won't be able to take it to Dr. T. .....ToT
But I found someone who seems to be the indicated. Apparently here is a very common mistake... Though me myself couldn't believed I had done it!
 I will tell you later on how this sad story turns into a (hopefully!) happy end!
Again I am very thankful for all your replies! 

Showing Posts 1 - 7 of 7

You must be logged in to post a reply. Please log in or register for a new account.