Welcome to the Forum.
The vibration you're experiencing is definitely NOT normal from all I've heard of this machine.
Questions?
1. Is it on a bench or a stand?
2. Is the bench/stand fixed (to the wall or floor)?
3. Is the machine fixed to the bench/stand?
4. Are all the machine feet present?
If the answer to any/all of the above is No, then fix those points first. If all OK in the above departments, then you've a problem with your machine. Again, Questions:
5. New or S/H?
6. Has this machine always had the problem or only just started?
7. (as posted above) - At All speeds or just some speeds?
Then:
8. Carefully check the machine all over for any loose nuts and bolts, tightening as you go (but NOT using 12 foot long wrenches)!!!
9. Carefully check the arms in all planes - are any bent?
10. At slowest speed, does the blade move back to front (as well as up and down!) when looking carefully from the side.
11. Ditto, does the blade move side to side (as well as up and down!) when looking carefully from in front/from behind?
If the answer to either both of the above is Yes, then either an arm has got bent (unlikely if the saw has not been dropped/badly mistreated) or the bearings are worn/very dry.
When you've answered all the above come back again and post the results and someone here will be sure to help you - there are very knowledgeable and helpful people here.
One or more pictures will help, but as a new member you will not be allowed to post pix until after you've made (I think) 5 posts.
HTH
AES