The Remington Noiseless Portable required still quite a whack at the keys, my particular specimen needed this to make an even imprint. Hitting the keys without a firm (staccato) wallop, would make an uneven imprint, with the top half of the characters very light or not even there.
This is then of course a case where the carriage and platen sits a bit too low for the type striking the platen, with most of the force on the lower half of the type. Given that the carriage rests on a single, small screw in a lip extending from the frame, it is probably logical to have sagged a bit over time. Having looked at it now for a while, finally grabbed some tools and had a go at adjusting this.
Most amazingly (to me, at least) there are two screws in the RNP to adjust the height of the platen for lowercase and for uppercase. The screws have of course a lock-nut to keep them in place during use. (Haven't quite figured out how a left-right height adjustment is done, but that was fortunately still ok :)
All the tools that were needed, are a small screwdriver and a 1/4" open wrench. Having tried first of course with metric tools, luckily had an Imperial wrench of the right size. (Actually used an Allen key, but also not an allen key...)
Started by making sure the imprint of the lowercase is nicely even. Lowercase has the p and q for the lower and the d and b for the top of the needed imprint, so with a bit of trial and error the lowercase can be adjusted to make an even imprint. Striking several times a letter from firm to very lightly to make an increasingly faint impression gives a good cue to see if the platen is properly centered in front of the type.
The lowercase rests on the screw, so clockwise will raise the platen. The uppercase pulls on the adjustment screw, clockwise will lower the platen.
With the lowercase adjusted, the uppercase will be out of line. So as the next item loosened the lock-nut. A small wrench can just squeeze in to loosen the uppercase lock-nut, parallel-beak pliers that can work on the lowercase just couldn't get there.
Result now is a Noiseless Portable that is much less critical about the typing force with a more even result on paper.
(Still needs staccato typing, the letter a is particularly sensitive. Must be another adjustment somewhere on the machine for that :-)