ELECTRICAL SMELL AND SOUNDS ROUGH

If blender blades are realy turn to slow in most cases the armature of the motor can having a few bad collectors where the carbon brushes can be to short but have been warned of the risc to order new carbon brushes that they can be becomes as short as the old ones in a real very short time, so make a ohm measure of the armature collectors over the carbon brushes if there is a thermal closure in the anchor(armature), in most case you can smell the problem or hear it and sometimes feel it because the motor becomes hotter then normally that its no longer has the right speed anymore.
Replace the blender is most times marketing technical an better option then repair it. but its in priority depend most on the brand and price.

Sounds like the extractor bearings may be seizing due to rust.
This YouTube vide should help see if it’s the same thing and how to fix it!
Good luck
https://youtu.be/Iw6VXRSHyNM

If the same problem exists when the pitcher is not on the base, the base needs to be replaced. It could be that the blade bearing is dry/rusty. In that case replace the blades. Either way, continuing to run the unit in this condition will fry the motor.

Sounds like the gear is stripped inside

Does the blade turn by hand? Does the motor turn by hand? The answers to both those questions may point you in the right direction. If both turn freely I would suspect you need a new motor.

Sounds like you have wrecked something, you just place the beaker on the motor base, no turning required.

Ouch. That doesn't sound good.
Is the blade seating & locking on the spindle? Try turning it with your hand (unplug the blender first!).
Examine the underside of the blade, and the spindle, for cracks.

If you find a problem here, it may be a simple matter of replacing the blade assembly.

If not, try running it dry... no blade, no container. Just short shots of one second. Is the spindle turning? If it turns, then put the container & blade back on... but just put water in the container.
If the blade turns, whipping the water (but doesn't turn if you put something more dense in it), that suggests that your bearings are going out.

In summary:

• If the spindle turns but the blade doesn't turn, look at your blade assembly. (Plastic can hide a crack.)
• If the spindle turns "sometimes", but not when subjected to resistance, then it's probably worn bearings.
• If the spindle doesn't turn at all, then your blender will need to be professionally repaired or replaced.

Sounds like the teeth are stripped underneath the blade. Make sure it's put together correctly before you do anything else.
Download Cuisinart CBT 500 Manual

It sounds like a gear might of broken either under the blender jug or in the unit itself. Best bet is seek out an appliance repair shop locally.

I had this problem and, after seeing these posts, was motivated to avoid paying the cost of a new blade unit. Here's how it can be fixed:
1. Take a kitchen hotpad and hold the blade (top) side of the unit in your hand as you unscrew the rubber gear on the base. This is a left-handed screw, so you must turn it clockwise, to free it up. This should be doable by hand. Be careful, removing the gear exposes a washer note which side is up, and place both the gear and washer aside.
2. With the blades held in the hotpad, unscrew the top nut, again clockwise. This takes more effort, but it will eventually give way. As this nut comes off, it exposes a rectangular post, to which everything is attached.
3. Remove a washer with a rectangular cutout. Make sure you remember which side is up (I think it makes no difference). This may require some rocking to remove the washer from the round-threaded end. It will come off.
4. Remove both blades in a similar manner. Note their orientation, which is important.
5. Next, remove a rubber gasket. On mine, it has a groove which is asymmetric. I don't think the orientation is important, but, again, you may want to note it.
6. What is left is an axle inside a sleeve. There are no bearings. In mine, I had to tap/drive this out. Take a flat-ended rod (ideas: I used the hex-shaped post end of a nut socket. An old drill bit you don't care about, rotated would also work). Place the unit on the edge of the counter, up-side pointing up, in a way so the bottom end of the axle could fall free when you drive it out. Gently tap the axle through the unit, using the helper tool when the axle is within the sleeve. It will drive completely out.
7. Clean everything. I simply scrubbed the axle and took a small brush to the inside of the sleeve. This doen't need to be perfect, but anything left on either surface may ultimately impair the functioning of the axle.
8. Lubricate the axle with household oil or a dab of grease. You will find that the axle will now slide into the sleeve fairly easily (I had the best luck from the top.)
9. Reattach the base gear, then the top in the obvious order. Everything should spin freely from this point on.
REMEMBER: always use the hotpad whenever you grip the blades and to tighten the bolt on top so that the axle protrudes slightly above the nut.
Good luck!