Stylus not tracking and sounds terrible

I'll be moving the amp. I moved it next to the TT temporarily while waiting for some longer interconnects. What could the amp be doing to the cartridge to move the cantilever though?

There was electrical work done during the renovation. Power was turned on and off etc. but nothing in the system was unplugged.

There are very powerful magnets inside the  cartridge. Amps have large transformers in them that generate strong magnetic fields. Need I say more?

mijo, I very much doubt your hypothesis, if you're implying that there is magnetic pull between the amplifier power transformer and the cantilever. Transformers do generate EMI (electro-magnetic interference) but not very much magnetism. And cantilevers are not ferrous.  Could EMI from the amplifier be degrading the sound? Yes, and maybe that is what you meant.  If so, sorry.  EMI usually causes problems by feeding back into the AC supply at the wall outlet.  Try plugging the amplifier into a different outlet, if it is now sharing with the turntable and/or phono stage.

Seems there are possibly two issues which may or may not be related.  The cantilever is not straight, but it was not straight for a long time before the sound went bad.  Possibly it bent past some critical angle and now is hopelessly out of line with the internal generator of the cartridge, or possibly EMI from the nearby amplifier (or some other undiscovered source of interference) is the culprit.  But anyway, the cartridge is now broken, is it not?

mijostyn- inverse square law. Need I say more?

nolacap- that cartridge is worth trading in. Don't mention condition, they don't care anyway. They only care that you're buying one of theirs. Which is a good choice, Benz are fine, had a couple myself. Just check this time first not years later! 

One thing that never was clear was if the cantilever was at an angle because it was bent or because the whole motor assembly was out of alignment. Anyone saying bend it straight had to be assuming bent, but the indications are more likely the whole assembly had come loose and was crooked. The cantilever got the blame simply because you could see it.

So this is one thing to always check anyway. Before unpacking look real closely. With the cartridge upside down and you looking down on it, the cantilever should line up perfectly parallel with the cartridge body. Equally important the stylus should be in-line and pointing straight up. I'm talking vertically. Straight at you when viewed from above.

If these aren't like this send it back. No amount of cartridge alignment will ever correct these faults. 

It seems to me you may never have heard anything but a damaged cartridge. Or in a very long time at any rate. Its not just the little channel imbalance you noticed. Unbeknownst to you the whole sound stage was being ruined. A new Benz properly mounted is gonna rock your world!

So, the transformers in the amp are about three feet from the table. Next to the TT on the shelf but on the opposite side of the arm. I’m not sure that matters or if a TT could be affected by a transformer being located that close. I considered that when I moved the amp but my only other option at the time was putting the amp on the shelf below the TT which seemed worse.

The cantilever is not bent. It’s straight but is being pulled to one side by the motor. The assembly doesn't look to be crooked in the body. The cantilever just pulls to one side. I can pull it back to center and then it rebounds towards the other side. 

Following Elizabeth’s advice I massaged the cantilever towards the center several times and got the cantilever off the metal hole it sticks through in the body. Not completely straight, but not touching the metal body.

It now sounds fine but I have no sound in one channel. I swapped the cables to confirm that the cartridge is only providing a signal through one channel.

I’m thinking there is a defect in the motor assembly that is pulling the cantilever more strongly to one side. Maybe it was something progressive that got worse over the years and/or maybe something happened that tweaked it far enough to finally hit the housing it sticks out through.

Either way, I appreciate the input and help everyone offered, even Slaw, and consider this a sign from the universe to make an investment in a new cartridge after nearly 20 years.