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HARMONIUM REPAIR & MAINTENANCE

Do's

1: Keep the instrument in a cool (never below freezing) and dry location. Use a cover or box for storage.

2: Use the harmonium regularly, move all stops and play all keys. This will stop the mechanism from jamming and reduce reed corrosion.

3: Before you start to play, pump the external bellows to fill the internal bellows until some pressure builds up
Don'ts

1: Do not leave the instrument in the trunk of your car or outside. Do not ever leave the instrument in sunlight.

2: Don't allow children to hit the keys or over-pump the bellows

3: Don't allow anyone to tamper with the springs, action regulating screws, or reeds.

4: Don't turn the damper or drone knobs, as this will cause air leakage.
Common Problems With Harmoniums
Sticking keys
The most common problem with harmoniums is sticky keys. The way to fix this depends on the type of action in your harmonium (see the diagrams below and identify the type of action you have).
The Solid Key :
With the expansion and contraction of the wooden sound board, the guide pins and hinge pins can be moved out of vertical position. These pins need to be realigned into vertical alignment. This will center the action and stop the key from binding.
The Stick and Pallet :
This type has no vertical pins to give problems; the guide pin and pivot rail are usually the culprits. The key has to be carefully removed from the pivot rail. Then the friction areas need to be lightly sanded and a little fine chalk applied (do not use blackboard chalk as it has anti-squeak wax in it--sidewalk chalk is ok).
The Stick, Lever, and Pallet:
The pivot rail fix is similar to the Stick and Pallet, however there are more parts involved, including the coupler sticks which run diagonally underneath the keys, and the lever pins. The coupler sticks have vertical pins that can cause the sticking. To access the coupler sticks and the lever pins requires a complete disassembly of the keyboard, scale changer, and coupler. This is a job for professional repair person.
Sometimes there can be other causes for sticking, such as: twisting of the wooden shafts which can cause the key tops (the plastic area where your fingers touch) to bind against their neighbors, and swelling of the woods in damp weather. To free-up these keys sand them along the sides.

Buzzing Reeds and Tuning

Buzzing Reeds
Buzzing or rattling reeds are usually caused by the soundboard shrinking, which closes the gap between the reed block and the reed tongue. This can be remedied by releasing the mounting screws, loosening the reed from the sound board, then re-tightening the screws. If this doesn't fix the problem, a new reed may be necessary.

In some instances buzzing can be as simple as a loose reed. If this is the case, it can be remedied by tightening the mounting screws. Sometimes these mounting screw holes are stripped and need to be filled with a tooth pick dipped in glue. After the glue is dry, the toothpick must be carefully chiseled off level with the sound board, and then a 1/16" pilot hole drilled, and the reed remounted.

Sometimes buzzing or false tones can be caused by dirt stuck in the between the tongue and the reed block. A metal scraping, or a wood scrap is the common culprit. These can be removed by gently lifting the reed tongue with the butter knife or a razor blade; the offending particle will come right out. Be very careful not to deform the reed.
Harmonium Tuning
Harmoniums are tuned to the western equal temperament scale. ( which means that each note is equally out of tune by a very small degree) Tuning harmonium reeds is a very exacting procedure, and I do not recommend that it be attempted by the untrained. However there are many folks who understand the precise nature of tempered tuning, and want to learn how to do their own tuning work, and for them I will detail the procedure.

The Tuning Tools.

 
The tools above are an engraving triangle pointed chisel, and a butter knife with a curved and thinned blade. The butter knife has been thinned to a razor blade thickness so it slide under the reed tongue without distorting the reed. The butter knife is used to support the reed while the scraping process is done with the engraving tool. I make my own tools, but a simple razor blade and an Exacto knife can work quite well. Reeds can be 4" long and as small as 1/2". Great care is needed with the small reeds.
Tuning the reeds
When raising the pitch of a reed, you have to scrape minute amounts of material from the tip (the first quarter of the reed). When flattening the pitch, you have to scrape the back area of the reed (the fourth quarter of the vibrating section of the reed) near the rivets . This must be done in a very uniform and even manner or the reed will lose its balance and produce an impure sound.

The quality of the tuning process depends on the correct air pressure being maintained throughout the full range of octaves. By pumping less on the small reeds and more on the bass reeds you can arrive at a pitch balance. If you don't balance the pumping, the reeds will not entrain (synchronize pitch) properly. When a reed vibrates under higher pressure, it will play a lower tone than with lower pressures. The bass reeds can move as much as a quarter note between high and low pressures. This is a matter of sensitivity, experience, and intuition .

The basic tuning principle for Equal Temperament, is to make the fourths wide, and the fifths narrow (at middle C, they should beat against each other at around one beat a second; at one octave above middle C, 2 beats a second; at one octave below middle C, 1/2 a beat a second).

To begin you will need to isolate one set of reeds, by closing all the other stops except the one related to the selected bank of reeds. Do not start with the bass set, as they drift too much as the pressure in the bellows varies. You set the temperament by tuning a sequence of fourths from middle C up: middle C - F - B flat - E flat - A flat - D flat - G flat. Then a tune a sequence of fifths: middle C - G - D - A - E - B - G flat (all within the first octave starting from middle "C"). If you arrive at the same G flat, then your tempering is correct. Once the selected set of reeds are tuned, you can open the other stops and tune the bass and treble reeds to the tuned set. Once all banks of reeds in the center octave are tuned, you tune all octaves up and down from the center octave. Mastering tempered tuning usually that takes an apprenticeship or a piano technicians course, so be patient.

In some harmoniums there is air bleed between chambers, due to warped timber or leaky seals. Then you will need to place strips of paper under the tips of the offending reed banks, in order to get a single reed to sound. If the harmonium has air escaping from the bellows, or the outer seals around the air chambers, then it can't be properly tuned until the leaks are fixed.

WARNING - Over tuning the reeds will cause them to loose their clarity and volume.

Mathematically speaking, the formula for arriving at an accurate equal temperament, is to multiply the starting point of "A" 440 hz. (The US standard) by a factor of 1.059463. This result will be "A#" 466.16372hz. Then you can repeat this process ( "A#" 466.16372hz. multiplied by 1.059463 = "B"493.8832132824hz) up through the octave. The best electronic tuner for this work is the Peterson Autostrobe 490.