Shielding an organ

[wagonman76]

Whenever the wife and kids are playing on their cell phones, the organ goes nuts. Same way it affects a nearby radio or computer speakers. Gets to where I just have to pack up and quit.

Has anyone successfully shielded an organ to prevent this? I'm guessing line the housing with glued-on aluminum foil?

[Jan Girardot]

Hi;

Assuming that the M75 is the organ in need, try lining with copper screen wire. If you would like to buy a service manual, I have one @$8 + shipping. Contact me at jan@theorgangrinder.net

. . . Jan
the OrganGrinder

[indianajo]

I've shielded a mixer, which is the same problem. I started by putting it in a steel box. Then I put 20-80 pf caps from the inputs to signal ground to short out RF that way. Then I put RF chokes on the AC lines coming in. I salvaged the RF chokes from dead PCAT power supplies. They are toroids, only have 4 wires, and I deleted one winding, leaving 20 turns on the toroid in series with the AC input. I had another one on the AC neutral coming in.
A good source of steel panels you can cut to size is old desktop PC cases. I use a cutting wheel attached to a 4.5" auto body grinder. Use safety glasses and a vise.

[wagonman76]

Sounds like something I could do. I've got quite a few old computer power supplies laying around. And I am an engineer for a metal fab shop so I do steelwork all the time anyway. I hadn't thought of that but I do have a roll of light gauge steel stored out behind the house. I'll have to get it out when the snow goes away.

Jan, I might take your offer for the service manual. I'll send you an email.

[Hamman]

I have a SS circuit added into one of my Hammond A105 (a bass boost circuit)anyway, I get all kinds of interference when I lay my phone on the music rack. I also mix live audio sound part time and can't keep my phone around the mixing console and or rack of components for that same reason. Usually on both cases if I just move my phone 2-3 feet away I don't have any issues. Be interested what solves your issue

[wagonman76]

I don't have any other place to put the organ except in the entryway in the kitchen. The phones being used are in the kids bedroom and living room. 10-15 feet away, and through a wall.

Yes it is the Kimball. My computer speakers go nuts too, even when the power supply to the speakers is off. I find that to be weird.

[knollr]

Real hard to reduce it to acceptable. Dam frequency with lots of umph! Would be easier to get them to go in the garage!

[wagonman76]

Sure wish I had a garage. Then it'd be mine! I'd have a place to work on the cars besides out in the snow and darkness. I'd have both organs out there, my basses and amps, all my tools and stuff to work on things, rather than scattered into every cranny I can find through the house. I'd probably be out there more than in the house.

[jdoc]

no you would end up like me with more stuff........

[Lucien Nunes]

You probably don't need to shield the whole organ - it might be possible to localise the sensitive parts of the circuit with a bit of systematic experimentation. Shielding schemes for any kind of kit are always less effective and more complicated than you would hope for, but suppression and bypassing of RF from critical circuits using grounded caps and series inductors as Indianajo describes can be very effective.

I wonder whether there is something wrong with the organ at the moment such as a ground lead off somewhere. I have never heard an organ to be so sensitive to phone RF.

Lucien