A carriage that does not move is the single most alarming thing a machine can present, because it looks like the whole typewriter has quit. In practice, the fault is one of six specific problems, and they are ordered from most common to least. Work down the ladder and stop as soon as the machine responds.

Rung 1: the carriage release lever

The paper release lever, the margin release, and on many machines a dedicated carriage release either disengage the escapement or free the paper grip. Confirm you are not fighting the machine's own safety. Return every visible lever to its neutral position, close the paper release, and lift the carriage return lever off the carriage. This solves perhaps one jam in six, and takes fifteen seconds.

Rung 2: the shift-lock

On many portables, an engaged shift-lock places extra tension on parts of the linkage and can prevent the escapement from releasing. Press and release the shift key firmly, then attempt a normal keystroke. If the carriage advances, the shift-lock was engaged.

Rung 3: dry rails

The carriage rides on two smooth rails, one at the front and one at the back. Sixty years of dust bonded with old oil turns them from ice to sandpaper. Wipe both rails with a lint-free cloth and a small amount of odorless mineral spirits, then a dry cloth, then a single drop of light instrument oil spread thin. Rock the carriage side to side and try to move it. If it now glides, you are done.

Do not soak the rails. Do not oil them heavily. The rails want a molecular film, not a puddle; excess oil migrates into the segment and creates a new set of problems.

Rung 4: the drawstring

The mainspring pulls the carriage across via a slender cord — usually braided cotton or nylon on machines from the mid-century on, sometimes a fine chain on earlier machines. This cord runs under the carriage from the mainspring hub to an anchor peg on the carriage rail. It breaks. When it breaks, the carriage sits still and no keystroke can move it.

Diagnosis: reach under the carriage with a fingertip and feel along the cord path. If the cord is loose or entirely absent, that is the fault.

Replacement is the most rewarding beginner repair in the hobby. Nylon fishing line rated 30 to 40 lb test is the accepted replacement material. Cut a length about a foot longer than the original, tie a bowline to the anchor peg at one end, feed the line through the routing exactly as the old cord ran, and tie the other end to the mainspring hub. Wind the mainspring three to four turns under gentle control, confirm the carriage now snaps to the right when the escapement releases, and adjust tension until the carriage returns smartly without slamming the margin.

Every model differs slightly in cord routing; a service manual or a good photograph from a working example of the same model is worth the ten minutes it takes to find.

Rung 5: the escapement

The escapement is a two-toothed pawl that releases one character's worth of movement per keystroke. When it is dirty or misadjusted, the carriage may lock in place, may release two characters at once, or may run away in a slow drift. Cleaning is one drop of light oil on the pivot after a solvent wipe of the surrounding area; adjustment is a specialist procedure that varies by manufacturer and is usually not required unless the machine has been dropped.

If the escapement is completely locked, back-drive one keystroke: hold the space bar and gently push the carriage right one character while releasing. Repeat if the mechanism was stuck against a hard limit.

Rung 6: bent frame or dropped internals

Rare and expensive. A cracked mainspring case, a bent carriage rail, a warped frame from being dropped on a corner. Visible in a careful inspection: the carriage will not sit square on its rails, or will only bind at one specific position. This is a donor-machine problem more often than a repair problem; if the machine is common, budget replacements are cheaper than the tools required to correct frame damage.

After the fix

When the carriage moves again, do not celebrate by typing a paragraph immediately. Cycle the carriage across its full range four or five times by hand to seat the fresh lubrication, and only then load paper. On a machine where the drawstring was replaced, retype the alphabet and confirm the carriage returns quickly enough for normal typing without slamming; adjust mainspring tension a quarter-turn at a time until the feel is right.

A carriage repair usually reveals what else the machine needs. If the mainspring is weak, the rails are ready for oil, and the drawstring has aged into brittle rope, all three are worth handling in one bench session while the machine is open.