An ear broke off the paper holder on my Swintec 1146 CM typewriter. Is a replacement part available and if so, where?

I suppose you are using carbonized paper to obtain 2 copies... Then probably the first sheet of paper you are using (the one over the carbon paper) is too thick. I remember that when one wanted to make copies, it was important to use thin paper or the copy (the page under the carbonized paper) would appear too pale. Try with a thinner paper, especially as the paper used in printers and photocopiers is stronger than the one that was produced for typewriters.

Swing the lever located below the ribbon carrier to the right to release the ribbon then lift up

You most likely need a new keyboard contact strip or at least a keyboard tear down and cleaning.

DickyO

Type a letter, press the key with the large X on it, if it dosen't correct but makes all the motions you probably have old supplies.

DickyO

Either there is a bind in the platen (roller) or there is a piece of paper or other object caught in the feed rolls.

I believe the swintec is identical to a Nakajima model. Go to NADIST.COM, click on current models, you will find a manual there.

DickyO

Go to the L. margin press but don't hold mar rel, space or backspace to desired position, press L. mar key.

DickyO

If you are saying that the "M" key dosen't enter you can try this. Gently Pry the keytop off, Make a small paper spit ball, push it down the hole below the keytop, reinsert the keytop.
If one dosen't do it try two. If this doden't work you will have to replace the contact pad inside the keyboard.

DickyO

You may be able to get a manual @ Nakajima 800-809-7138 they made the sintecs.

DickyO

try typing on different paper also try typing on the heavy setting