|Davis Bros. Online Typewriter Maintenance and Repair: Simple problems or complaints and their remedies.|
|For the purpose of this self-guided online approach, it is convenient to discuss problems not based on their operative functions internal to the machines, but rather as related to the operative functions as experienced by the typist. We can then divide problems with the machines into general categories.
1. There is a problem that occurs when I try to type on the machine.
2. There is a problem that occurs when I try to move the carriage by hand.
3. I can type on the machine, and the carriage moves, but something else is not working properly.
Let's take a look at these three things in order and examine some common and simple problems. Remember -- we're assuming that the BIG TEN problems on the previous page have been eliminated!
|1. There is a problem that occurs when I try to type on the machine.|
|DISCUSSION: Depression of a character (letter or number) key must cause the type bar to move to the printing point, at which it enters the print alignment fork and contacts the ribbon, making the impression on the paper wound around the platen. The type slug is that small part actually containing the type; the side with the letters on it is known as the 'type face.' The type bar then returns to rest with all its friends. During this operation, the action of key depression and type bar movement must trip the escapement, which allows the mainspring to pull the carriage one space to the left allowing for the next letter to be typed. If a capital letter or number/figure is to be typed a shift key must be depressed while the character is typed.
Having seen the above, we can identify a range of problems already. First, in many portables it is common to have one or more type bars disconnected from the key levers. This is particularly common on Smith-Corona portables. This can be caused very often by excessive piling up of type bars, such as when a child has pounded on the machine. These are easy to fix problems on Smith Corona machines -- look inside and you'll see that there is a fork-type connection in every linkage, and that it can be reconnected with a pair of long, needle-nose pliers. You can gently 'jam up' several other type bars at the print point to allow access, from above with the top cover open to make this easier. I have had to reconnect over twenty at one time on ONE machine because of this type of failure. In the big picture, if a key is depressed and a type bar doesn't move at all you either have a disconnected linkage, a broken linkage or a missing part. Reconnection is simple since all the others are made the same way; broken parts and missing parts require spares, not commonly available today.
Let's now suppose that keys depressed cause the type bars to move up SOME but not all of the way, and that NONE will hit the ribbon. This is most often caused by the "line lock" or margin set feature, which interrupts typing at the end of a line. Is the margin set properly? If it is, then the line-lock mechanism is likely jammed and will have to be freed up. Make sure the margin release key is fully UP and not jammed down. Move the margin set stops all the way out left and right and see if the machine will not operate properly. We'll get more into this failure later.
Now, let's assume that the type bars can reach the print point and ribbon but don't return to rest. If they jam hard at the print point, they're bent and are getting stuck in the print alignment fork. You'll have to VERY VERY CAREFULLY make slight adjustments -- and that means corrective bends -- in a type bar that always jams at the print point. You should check for burrs in the type bar itself that can cause this problem too, but most often they're bent if they jam tight. If they move back down sluggishly, either the segment in which they're mounted is dirty or else a spring is disconnected or missing. Make sure the type bars are clean all the way to the bottom; you can just scrape off gunk or use a volatile cleaner that will evaporate (NOT penetrating oil or WD40.) Also make sure there aren't eraser crumbs or grit in the segment. If this is not the case, then a type-bar spring is a likely culprit. Each type bar normally has a spring associated with it, connected somewhere in the linkage to help return it quickly to the rest point. Look for a battery of springs all in a row inside the machine, and watch as you operate keys to see how they flex and provide 'return power' for the type bars. Look to see if the offending "slow returner" isn't missing a spring, or if it isn't disconnected.
Of course, all of this may operate properly -- the machine might type along quite nicely, but the letters typed aren't coming out right. When each letter is typed, the ribbon must both be raised to the proper color for typing, and it must also move along to expose fresh ink. If the ribbon doesn't raise up properly, check that the color selector isn't in the "stencil" position which cuts it out entirely. If it won't move along, or feed, try reversing it manually either by use of ribbon reverse lever or else by movement sideways of the ribbon forks that the ribbon passes through on its way into or out of the spools. Sometimes, with this latter operation it can be found that a machine will move ribbon in one direction but not the other due to wear of small parts or else missing springs. I own several very old machines which, due to this failure, only move ribbon one way. I've decided NOT to repair them, as this is easy to overcome by manually winding the ribbon back when exhaused. Consider this point if you wish to avoid complicated repair on a machine you wish to use -- or consider it more strongly for one you only use occasionally! Fixing either of these (ribbon lift, ribbon movement) doesn't really fall under SIMPLE repair and fix, so we'll get back to those on a later page.
The final problem we'll examine here is that of carriage movement related to typing -- let's assume the carriage doesn't move but all other functions, such as type bar action and ribbon action seem proper. This is most likely caused by mainspring or drawband trouble, which we'll examine in a following section.
|2. There is a problem that occurs when I try to move the carriage by hand.|
|DISCUSSION: The carriage of all modern typewriters can be moved left and right through the use of carriage release levers, which may be on one side of the carriage only or on both sides. These levers disengage the carriage from the limitation of the escapement and allow it to move freely side to side. Motion of the carriage to the left is always aided by the power of the main spring, connected to the carriage by a drawband; motion to the right is against this main spring tension. Movement of the carriage is limited in most cases by the margin stops, used to limit carriage travel on the ends of the desired writing line. Bypassing of these stops by the margin release key allows full range of travel limited by mechanical design, from "0" on the scale to the upper end of the scale.
There are likely more complaints and problems found concerning this function than are immediately apparent, and very many are caused by dirt or lack of proper lubrication if the complaint centers around rough or noisy movement. Binding of the carriage can be caused by outer panels that are improperly attached, causing rubbing of the carriage (particularly true if the machine has been dented, banged or dropped and a rear or side panel is moved up to be able to contact the carriage.) Check both sides, behind and below the carriage to make certain nothing is artificially impeding progress of movement.
If there's no tension whatsoever on the carriage it's certain that the drawband is either off or broken... or else that the mainspring has become unwound or is broken. Putting the drawband back on is usually easy so long as the original hook or eyelet mounted on the end of the drawband is still in place. Wind tension back onto the mainspring, and then you can pull the drawband under the carriage using a long hook, a wire, a bent coat hanger, a very long crochet hook, fishing line fed through, or just about anything you can think of to get the drawband from the left side of the machine under the carriage to the right side where it attaches. If it is broken, it should be replaced. Sometimes it's possible to use craft edging or heavy ribbon for this, or else fishing line. Look at craft stores long enough and you'll find a number of substitutes for drawband -- remember though that they CANNOT be elastic! Crimp-type wire connector lugs can be used to replace missing drawband hooks in some cases as well. You'll be able to tell if the main spring is broken if the drawband is off and no matter how much you wind the spring drum backwards you can't get tension on it; note that on most machines a ratchet-style device is used to hold tension on the drum once wound. Make sure this is engaged properly so that tension remains. We will have a separate MAIN SPRING and DRAWBAND section on the site later on in the heavier repairs.
With the rate that machines are being shipped poorly packaged today, we often find that bent levers are a problem... in this case of carriage movement a bent carriage release lever might not move far enough to actually release the carriage. Sometimes, on machines with two levers only one is bent, limiting the other from moving far enough too if they're linked and move together. Examine the mechanism that is connected to the carriage release lever to see if the margin rack moves away from the escapement wheel; if it doesn't, there is likely an artificial limitation caused by misalignment or bending.
One frequent problem we've found on machines discovered in the field, believe it or not, is a stuck back-space mechanism. If the back space is stuck, the carriage won't move at all in most cases. Operate the back space and make sure the key returns all the way up when you release it. Pull the key back up if you have to. Free up the backspace and very often you'll "cure" a "totally stuck carriage."
Sometimes a carriage makes a grinding noise when moving. The carriage release may not be moving far enough to allow complete release of the escapement -- the rack in the carriage is brushing over the teeth on the escapement wheel, making a grinding or ratcheting sound. Ensuring the carriage release operates FULLY and freely cures this, and can often be the result of a bent lever.
|3. I can type on the machine, and the carriage moves, but something else is not working properly.|
|This encompasses a whole range of possible problems which will be better addressed as we make an examination of the various working parts of typewriters; the operative functions and requirements for various mechanisms will be much better understood there.
Keep in mind that anyone can turn over or open up a typewriter and follow a linkage to see how it works and what it does. Anybody can spot a broken part that's snapped off, or a linkage with a hole in it that obviously should be attached to something else with a screw. Things are not supposed to be waving around in space inside a typewriter!
NOW, let's move on to our examination of the various working subsections of typewriters so that we can examine some advanced mechanical concepts and thus better understand more complicated repair problems.
|Click the arrow to continue to working parts of typewriters.|