Hi all, I'm new here.  Recently acquired a Boegram 5000 (radial arm) with a MMC3 cart that appears to be in fairly good shape other than this.  When I hit play arm moves over guide track and drops down. When it does this the platter does a bit of a stutter, you can actually see it jump a bit, then comes back up to constant speed.  The stutter is manifested in the speakers by fluttering of the woofers.  Seems to go away once it gets up to speed.  It also does this when cueing up and down.  It's almost like the belt gets plucked -- odd.  Anyway someone suggested maybe related to the muting mechanism and replacing the belt might solve the problem?  The muting does seem to be off a bit.  There is quite a lag in one channel muting.  Any ideas before I order a belt I may not need?   Thanks all.   -Cubby

The cueing mechanism does use the motor to drive it. I wonder id a good clean would help?

Ok, Armed (armed and dangerous) with a service manual I popped the top of the deck off and looked around.  I think I see what's going on now.  The "stutter" is ocuring when the geared camwheels are engaged (start/stop and lift/lower) you can see the suspension shake as these gears mesh.  I can easily feel it rotating the patter.

The thing is at this point in time I think both channels should be muted but only one is.  So I hear the warble and see the woofer bounce on that one side as the gears mesh.  The channel does mute eventually but it's very late in the process.  I think I can live the deck if the mute is working as it should.  Otherwise I'll probably flip it.  I'm not sure where to look to fix the muting.  I really don't want to dismantle it any further if I can avoid it.

Thanks all. -Cubby

ps - it's amazing how much the default avatar looks just like me. :-)