Motion Sound AR-112

[David Anderson]

I had to repair a Motion Sound AR-112 rotary cabinet this week for a friend, and it was quite an experience.

I've done minor repairs to this cabinet before, but this was a major job. The rotor turns on bearings similar to the tensioner arm bearing in a Leslie 122, and the bearings are glued into the end of a plastic pipe that serves as the axle of the rotor. The bearings had come unglued, so I had to reglue them, which meant almost completely disassembling this thing.

Trying to get it all back together with the quirky system of o-rings and a spring used to keep the rotor in the proper vertical position on the axle was an total nightmare. The shaft the whole mess turns on would jam when trying to get it back in position. And it looks like you'd have to do this whole disassembly/reassembly process just to replace the belt if it ever broke.

The current incarnation of Motion Sound, last time I checked, has orphaned this speaker since it was made by the company under previous ownership. Its owner likes it because it's small, but its size is part of what makes it so difficult to service.

[clem]

I had an AR-112 at one point but didn't really get attached to it so I sold it. I've had a KBR-3D since 2003 and it's been a great piece. The one complaint I had with it was the fact that you had to remove both speakers and tweeters from the stationary channel and a total of 36 screws to remove the amp section to change the belt or adjust the trim pots for the rotary section. Luckily I've only had to change the belt once and the service tech with the old company sent me a template showing where to drill holes in the top of the unit to line up with the trim pots and where to drill a 1 1/2" hole that would make changing the belt possible without disassembly. (he says it's possible but looks pretty tedious to me) Also sent me plastic plugs to pop in the newly drilled holes. You would think that once the pots were adjusted to your liking that wouldn't be necessary but once in a while the horn or the simulated lower rotor will stop working and a very slight twist of a pot has always gotten it going again.
Kind of a strange company with very unique products. I love the KBR-3D and pretty much everywhere I use it I get asked..."What the hell is that?"