Anyone else encounter tender rattling at high volumes?

Nick,

I have the exact engine with the exact same problem.  There is nothing in the interior of the tender that is loose or rattling.  What is making the noise is the tender shell itself that is vibrating.  With the volume up high it seems to excite the natural frequency of the shell.  I tried using the dense foam from the ends of lionel engine boxes as a brace from side to side with little effect.  As with you if you just lightly pinch the outside of the tender shell the vibration stops.  Possibly a gasket at the plastic shroud to the tender base may help,but I am thinking about changing the natural frequency of the tender shell.  Maybe one of those HO self stick lead weights on the inside of the tender shell to change the sprung mass.

Let me know what you find works.  Also, thanks for the tip in the other post on the boxpok drivers.  I had been under the impression the engine was supposed to come with these.  I was surprised to find them on the Lionel parts site and ordered them up.  What a pleasent difference.

Thanks,

Greg

If there's room, try a piece (maybe 2) of 1/4" square balsa wood fitting snugly between the interior sides of the tender shell. This is likely to have the same effect as slightly squeezing the tender sides that you described earlier, which made the vibration "buzzing" stop.

Here's an update. Tried a combination of stuffing the tender's empty space with the foam and creating electrical tape washers and seating for the speakers as described above. Neither had any effect on the rattle whatsoever.

Here's a video of the issue with a demonstration of the brief "squeezing" remedy:

Tomorrow I will see if I can find any of that Dynamat material. If that doesn't work then I officially have no idea how to stop this rattle other than turning the volume down to the lowest level.

I wonder if the speakers could be rattling where they mount to the tender frame.

Maybe the speakers need to be snugged down, or perhaps some sort of cushion between the speaker and the frame. 

You could try running it with the tender shell off and see.

Other than that the vibration occuring in the middle of the tender shell is probably because there are no mounts there.

Washers where the screws are or foam behind the speakers is not where the problem is.

Its hard to tell from your photo, but I think you might need hard foam large enough so that you have to force it in between the tender sides creating pressure to absorb the vibration.

Maybe a small bead of silicone along the tender frame that is left to set up, then install the shell.

Just some ideas.

2 thoughts-

1. gasket under speaker mount to isolate from shell

2. make a cardboard sound baffle around the back of the speaker-craft glue onto the speaker frame- this would stop the sound from using the tender as a sound chamber.

FWIW I have a couple of these and neither has the rattle. I don't think its due to an inherent resonance in the tender body. You had it diagnosed in your first post. Its likely due to contact between the body and frame. I would try whats been suggested already and lay a layer of electrical tape along the edge of the frame. My second choice would be a bead of Mortite caulk. This will seal the edge but allow separation when needed.

Acoustic damping sheets will reduce the vibration of panels but I would try the simpler solutions first. Foam materials absorb the reflected sound waves. They might be used to quiet a room but not reduce vibration of a panel.

Pete

Addendum for your consideration...

The tender has no relief for the sound pressure created by the back of the speaker moving. This is only noticeable at high volumes, but it is always there.

I don't see any way to hide a vent on the coal. Sound out of the top and the bottom would relieve the pressure and sound better. I think you'll just have to dial it down little.

I don't think venting has anything to do with this personally.  The best sound from speakers is when you have an airtight baffle on the rear of the speaker, so the pressure difference would simply not exist in the tender.

Everyone - thanks for the further suggestions and I will try some more today.

1) Does the tender body/shell have any movable hatches, i.e. opening water hatches?

2) With the tender body/shell removed from the tender, try tapping vigorously with your finger nail, various portions of the body/shell.

1) No. All hatches are static.

2) As I described earlier, running a metal tool along the bottom edge of the middle of the shell reproduces the tinny vibration to a degree. So the problem is definitely there.

Good news though is the rattle has been solved. First new remedy I tried today worked:

"...lay a layer of electrical tape along the edge of the frame."

Hadn't thought to try this. I ran a length of cheap electrical tape I got from Radio Shack along the inside bottom edge of the tender body (so none would appear externally) and the rattle has vanished.

I suspect those two beams in the center of the shell were the primary cause. Which means Bill (mountain482) had this pegged early on. I misunderstood his post and thought he was talking about two center screw mounts, which my tender does not have. Will report back if I can isolate the rattle there.

Here's an alternate, much more permanent solution if you don't feel like fussing with messy tape: