Locating and Fixing a Problem With Your Piano


This section is provided so you may fix any small problem that may occur with your upright piano. Grand owners are advised to leave their piano well alone. The Guide should be used only in an emergency when a piano technician is not immediately available, rather than as a substitute for professional adjustment or repair. It should be used with reference to the five images at the bottom of this page. Click on the required image and scroll back down to the enlarged version. The original text remains shown for your convenience. Printing off the action diagram will prove helpful. All the repairs listed can be carried out by anyone who has a basic mechanical knowledge and apart from one or two exceptions, no tools are required.

Open the top lid and reach in and undo the clips inside at each end. Carefully remove the top that is secured to the back of the bottom lid by two dowels. Remove the lid that covers the keys by holding each end of the back piece and lifting it up evenly out of their respective piano slots. The bottom panel is removed by swinging back the two top catches at each end or by pushing up a spring clip in the centre. The panels should be carefully put aside out of the way.

Remove this only if necessary - some are very difficult to put back in! See photoset "Removing the Action". Undo by hand the round knobs at the top of each action bracket. Some older pianos have a tab at each end that are turned. Many very old "overdamper" pianos have a small knob in the middle and others have a small screw securing the centre of the action to the key bed. Once the bolts are removed, pull the action back. Important - look down behind the action on the left hand side and see how the sustain pedal rod coming up from the bottom of the piano fits into the metal damper lift rod bracket. If there is a pin on the rod protruding through a hole in the bracket, this must be put back in this position when the action is replaced. You will also see that the hole is bushed with a piece of leather or a little rubber grommet. Remember this!  Now carefully lift the action out of the piano. If it will not come out do not force it - instead, push the action forward again and re secure the knobs. On some very old instruments, the action is attached to the key board and everything has to be removed. Do not attempt to do this. Also spinet pianos have the action down in behind the keys making them almost inaccessible. Do not even consider removing an action from this kind of piano! Once the action has been removed, stand it somewhere well out of the way. Most actions stand up by themselves - some do not!

The bottom parts of the action brackets should fit positively back into the cups or holes on the back of the key bed. Make sure that this is so. Sometimes an action can appear to be properly seated when in fact it's not. Gently guide the top of the action forward so the top part of the brackets fit on to the bolts protruding from the back plate of the piano. If the sustain pedal rod fitting is as described above, ensure that the pin on the top of the rod goes through the hole.The soft pedal bracket which is also on the left hand side, but closer to you, may also have a similar fitting, so that will have to be re attached as well. The sustain pedal rod can be difficult to fit and may require assistance to line it up by reaching in the bottom of the piano. Screw the action knobs on firmly. Play the piano to check that the notes do not "ring on". If they do, you have not fitted the action correctly. Re check the above. If all is well, depress both the soft and sustain pedals with your foot to see if they work. The sustain pedal on the right will cause all the dampers to evenly lift a few millimeters clear of the strings. Some pianos have a middle pedal and this will probably operate a mute strip and the operation and adjustment should be fairly straightforward. If the middle pedal moves only one section of the dampers, this is normal.

You cannot remedy this, as a special tuning tool is required and a proper tuning can be done only by a piano tuner. If there are only a couple of notes that sound bad, it could be that one of the three strings of a particular note has gone flat in comparison to the rest. See photo A "String Mute and Pedals". With the top panel removed from the piano, identify the offending trio or pair of strings and place your finger on the left and the right strings just above where the hammer strikes. If the sound dramatically improves, then you have blocked the flat string. To keep it blocked, wedge a small piece of thick felt or rubber between the string and the strings of the adjacent note. This muting method is not successful if the middle string is the one that is flat.

Accompanists complain that they have to "tune down" to your piano. A tuning fork or a budget electronic tuner will quickly identify the problem.  As above, you cannot remedy this and a piano tuner is required.  

If the string is blocking off several other notes, it can be removed by first removing the action and identifying where it is attached to the piano. The string can then be removed from the hitch pin at the bottom. Chances are that the string is shared with an adjacent one and that removal becomes difficult. Make a loop from the free part of the string and tuck it somewhere away from the rest. Resist the temptation of using wire cutters! Any string that is sucessfully removed should be rolled into a 6 inch diameter loop and left in the bottom of the piano away from the pedal trapwork. Do not throw it away!

To identify where the problem is, consider if it is the key or the action that is malfunctioning. If the key stays down after it has been depressed, then it is almost certainly the key that is causing the problem. Also however, with the use of the action diagram to identify the wippen, lift it and see if the hammer moves forward to hit the string. If it doesn't, then the problem is in the action and a technician will have to be called. If the hammer does go forward but doesn't return to its resting position, the flange probably needs a centre pin replaced and once again this is strictly a job for a technician. The workings of a piano action are complex and without the proper knowledge and special tools, it is one part of the piano where repairs should not be attempted. If the problem is a sticking key, then first check that it is clear of the key slip - the finished piece of wood that runs along the front of the keys. Next, check that nothing has wedged between the key and its neighbour. See "The Keys". It is common to find bird seed, mice droppings or other foreign matter jamming the keys. There may be a wooden rail running along the top of the keys just behind the key covers with a screw at each end. Remove this rail. If there are no screws, the rail may be held in place by pins. If it does not pull straight out, try pulling up one end and then the other. It should then come out. Removal of the sticking key may reveal an object such as a pin or a coin, which is causing the problem. If the key still sticks, the red cloth bushing on the centre top or front bottom may be binding on the centre or front rail pins. These can be enlarged slightly with the aid of some long nose pliers. Caution - a special key easing tool is really required for this and any excessive prodding with pliers into the bushing may prove to make matters worse. Do not touch the hole underneath the centre bushing.

If several notes together do not play, then suspect that a foreign object is lurking in your piano. A ball point pen blocks six adjacent white keys very effectively. Inspection down inside the action or under the keys will reveal a long object in the form of a pen, pencil or a ruler.
NOTE - do not be tempted to use, machine oil, CRC or silicon sprays such as WD-40 to free up sticking components. While the latter may sometimes be effective in freeing up sticking hammers, it leaves a sticky mess, which is difficult to remove. Piano technicians have a specially designed lubricant. Even this is not always successful and a proper repair has to be made.

Usually on isolated notes. Look carefully at the jack when you release the key and if the click is heard when the jack snaps back under the hammer butt, then the butt felt is worn or missing. This is inaccessible to the novice and must be repaired by a technician. If a click is heard when the back of the key comes into contact with the action, then either the capstan cloth (on old pianos) is worn through (and is easily fixed) or the cloth underneath the wippen is missing or worn. If it is the latter, then the action has to be removed and the cloth has to be replaced. Loosely fitting parts and failed glue joints in hammer and catcher shanks can click noticeably. If a hammer head rattles and is so loose that it comes easily off its shank, a little white glue in the hammer hole and a square replacement back on the shank should solve the problem.

Check that the action is properly fitted and secure. Over damper pianos are notorious for this problem and the rather inadequate bracket in the middle is often the cause. Depress the sustain pedal slightly and watch the dampers. If they release immediately, there is probably not enough "play" in the pedal. See photos B,C and D in "The Pedals" Adjust the (usually) simple mechanism at the bottom slightly and then re check the damper movement. If there is no difference even after several turns, re adjust the pedal back to where it initially was. The adjusting mechanism is usually in the form of a long thin bolt that protrudes up from a hole in the pedal and then through a wooden or metal rocker beam (the horizontal piece that extends from the pedal rod across to the pedal). A nut fits over the thread at the top of the bolt, which is what you turn to make the adjustment.

The damper for that particular set of strings may need adjustment by bending the wire that supports it. This adjustment is a very delicate one and should not be attempted as it could well make matters worse. If the damper is missing altogether, look down in the bottom of the piano and there's a good chance that's where it will be. With the action still in the piano, see how the damper fits by lining it up with the others. Apply a little white glue to the block (screwed to the top of the damper wire) and also to the head or red felt of the damper. Allow the glue on both surfaces to become tacky for a few minutes and then with the block pulled towards you, hold the damper against the string where it should be. Gently let the spring tension of the block move back against the damper so both glue joints meet. The damper should now be properly aligned with the strings which now should be effectively damping once again.

If there is a brief buzzing sound coming from a particular string as you release the key, the damper may have had water damage which has caused the felt to go hard. Remove the action knobs and pull the top back. Feel the face of the damper that touches the string to determine if it has gone hard. It will also be of a different colour to the rest. A few light strokes with some fine sandpaper or an emery board, may be all that is required to soften it. If the surface is really hard, short of shaving it down with a razor blade, the damper should be replaced, making it a job for the piano technician. Dampers are very delicate components and the slightest adjustment can have a very noticeable effect. Not done properly, an adjustment can often make matters worse!

Check to see that the rods going up to the action are intact and adjusted sufficiently to move the levers that they are intended to connect with. In the case of an ineffective soft pedal, the steel bracket may have become detached from the movable hammer rail. See Photos C and D in "Removing and Replacing Action". Older pianos have a piece of leather that joins the rods at right angles to their respective pedal rockers. If this leather has torn through wear, re glue a piece of similar material in its place.

As with other noise related problems, try to determine the source of the sound. Check where the pedal comes through the opening in the front of the piano. The felt or cloth around the inside of this opening may be badly worn or missing and the pedal may be rubbing against the bare wood. If there is no felt at the top of this opening, a distinctive clunking sound will be heard. Some pedal rods go up through a guide located just below the action. The guide is usually a piece of wood with a round hole bushed with cloth. If the sound is coming from that area, application of graphite to the rod where it passes through the hole may solve the problem.

Adjust it so that the felt strip comes just below the hammers when the pedal is pushed down and across to the left. If it is still causing problems and affecting normal playing, consider removing the rail entirely. Very old pianos have a similar celeste felt system that comes up from under the hammers, which can also be very problematic and may be better removed altogether.

There are many reasons that can cause these noises. Like the rattles in car, some are extremely hard to trace. Remove any items that may be sitting on the top of the piano (and leave them off). Sympathetic vibration may cause only one note to rattle. Remove the panels one at a time and keep playing the note. Check for any loose items such as hammers and action bolts. Press fingers firmly on various parts to see if sound ceases when doing so. Use a process of elimination. A major headache is the referred or sympathetic vibration - one that comes from a different area from where it is produced. Enough to drive you nuts. Light shades and crockery on nearby shelves can often be the problem. Check behind the piano to see if items like sheets of cardboard are not touching the sound board. A loose bridge or badly fitting bridge pins can affect the tone of the instrument markedly and nothing can be done by the non - technician to rectify this.

Once again, all the above remedies should be done only in an emergency. Should a problem arise under normal circumstances, the owner is advised to engage the services of a piano technician.

This page will constantly be updated. The content has been compiled with great care and with reference to standard trade procedures. Technicians are invited to suggest any additions and amendments/corrections that may be necessary. B.H.

  • The Panels Removed
    Arrows show where the action brackets fit into the back of the key frame and the bolts securing the top of the action to the piano. Arrows at the bottom of the piano show the pedal trapwork and where the attached pedal rods (hidden) go up the left h
  • The Action
    Side view showing components as they would appear in most upright piano actions. In smaller uprights, the key capstan screw (46) contacts directly with the underside ot the wippen (39), eliminating the sticker (42). From "Piano Tuning, Servicing an
  • String Mute and Pedals
    A: Temporary felt mute blocking strings (coloured red for clarity). B: Pedal rods. Left hand rod activated by soft pedal extending up inside piano making contact with action at the top. Right hand rod activated by sustain pedal extending up maki
  • Removing the Action
    A: Removing a Yamaha action. Arrow indicates soft pedal rod disengaged from hammer rail. B: Sustain pedal rod attached to damper lift rod (24). Note how pin projects through rubber grommet. This has to be refitted as the action is replaced in t
  • The Keys
    A: Worn cloth covering screw capstains in older type piano. B: Sticking keys caused by mouse droppings. Arrows show pin and coin jammed between the keys. C: Underside of key showing bushing that can bind on oval front rail pin (arrowed). Arrow
  • Removing Felt Mute Strip
    If the felt mute strip comes loose in your piano, I can email you an information sheet to deal with the problem.

All colour photographs on this website have been taken by Brian Holden

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