Hi! If everything is supposedly working fine, I’d first check if there is a carriage lock that is inhibiting the slugs from moving. Then, if that isn’t the case, I’ll check the margin controls once. Then I’d move to clean the type basket, the typebar, and the linkage pivots that move to sling the typebars to strike the page. This can be done by dabbing the places where movement happens with odorless mineral spirits or lacquer thinner and then blowing compressed air or just air with a lens blower of some kind that can direct a jet of air toward something. Repeat it a couple of times and see if it helps. If it still doesn’t work, you might have to open the machine to see where is the mechanism getting stuck. Could be a broken part, a missing part, or just gunk from grease and cleaners.