Solving Delhi Harmonium Problems Page 2
Many harmoniums have a coupler mechanism which couples the key one octave or below to the depressed key to get a fuller sound. In the picture below, the coupler mechanism is enabled by pushing the lever forward.
These coupler mechanisms can often cause clicks, stuck notes and other problems. They are usually very easy to remove and I can do it in a matter of a few minutes, and is recommended.
Remove the board on the front and above the stops. You'll see two hinges, one on each side.
The lower pair are the hinges that hold the key/reed board and the stop case together.
The ones above hold the coupler mechanism. Remove the two screws as shown in the picture and slide the coupler board out.
You can leave the coupler lever in place or remove it by looking under the keyboard for the other end of the coupler lever, removing the keys above it, and removing a screw or two to free the lever.
I usually bend the handle portion back and forth until the rod breaks, then remove both pieces.
To determine if you have a leak, or how bad it is, try this test…carefully.
Close all the stops and don’t press any keys. The goal here is to fully “charge” the bellows in the case of the harmonium, the one under the keyboard and reeds that you can’t see. Again GENTLY squeeze the bellows until there is a fair amount of resistance. Be careful here because you don’t want to cause more leaks! Now keep very gentle pressure on the bellows and estimate how long it takes for the bellows to fully close. It should take between five and eight seconds. If when gently squeezing the bellows you never feel any resistance, then you have a serious leak.
Leaks can come from a key that is not properly seated, which will usually cause that note to drone even when no keys are pressed. It also possible that the keyboard/reed board is not sufficiently tight and air is leaking around the edges. An easy fix you can do yourself is to remove the glass cover and locate the two big flat head screws towards the back of the instrument. Make sure these are really tight. If the screw will not fully tighten, the hole may be too large. I fix this by gluing a wood dowel the same size as the hole into the hole then drilling a new hole for the screw.
The more notes you play at a time, and the more stops you have open, the more air it takes to keep the reeds sounding so sometimes there isn’t actually a leak, but it’s how you play.
One possible cause of leaks, or a failure to play at all when you squeeze the bellows, is the flap or flaps at the back of the harmonium not closing. Some harmoniums have a single flap and others have two.
In this picture the right valve flap is slightly open.
It will seal once the bellows are squeezed and is normal.
In the case of another harmonium, the spring inside the bellows had come slightly loose and rotated down. The flap caught on the spring and never closed. When the owner played it, no sound came out as all of the air leaked out of the back.
The spring is out of position and was catching the valve flap.
The back plate was removed and the screw holding the spring was loosened and the spring rotated clockwise to move it farther to the left and out of the way of the valve flaps.
Here is the spring in the correct . Make sure the screw is tight.
You might consider removing the screw and adding a washer so the screw can hold the spring tighter. This is best done with the harmonium on its front so the spring doesn’t fall down into the chamber.
MAKE SURE THE SPRING DOES NOT CONTACT THE INSIDE OF THE BELLOWS! If it does, you could wear a hole in the bellows and that would be bad.
Finding leaks can be difficult. Using a stick of incense to move around various places in and around the instrument while gently pumping the bellows and observing the smoke can be helpful. The smoke should rise fairly straight up, but when near a leak, it will get blown around.
Close all the stops when doing this and pump the bellows gently. You should not squeeze if you feel resistance.
Check the paper cover in the back of the stop board which is at a 45 degree angle. Also check all around the bellows. Be aware that around the gap between the inner and outer case (assuming a collapsible harmonium) there will be air flow when pumping the bellows. This is because pumping the back bellows directs air through that manifold and into the bottom bellows, which expands downwards, forcing air out along those edges.
Check the paper cover which covers the manifold which funnels air from the bellows into the reed chamber. See the picture to the left.
Also check all around the bellows. Be aware that around the gap between the inner and outer case (assuming a collapsible harmonium) there will be air flow when pumping the bellows. This is because pumping the back bellows directs air through that manifold and into the bottom bellows, which expands downwards, forcing air out of the inner case along those edges.