How to Fix Key Weights in a Kurzweil Electric Piano
- 1). Troubleshoot the piano. Turn the piano off and play each key, starting with the lowest. Listen for clicking or rattling as you press the key. Stick a piece of electrical tape on any key that rattles or clicks. This is a sign of a loose key weight.
- 2). Turn the piano back on and turn the volume dial to the level you normally use. Typically, the volume slider on a Kurzweil is located to the left of the control panel, above the keys. Play each note again, but this time listen for dips in volume between keys. If one key is noticeably quieter than the preceding and subsequent keys, mark it with electrical tape of a different color. A change in dynamics between keys is indicative of a problem with the key contact element of the key.
- 3). Unscrew the top of the piano with a Phillips screwdriver. Remove the top panel to expose the keyboard assembly. The number of keys varies depending on which Kurzweil electric piano you are repairing. The SP4-8 model has 88 keys and the SP4-7 has 76, for example. You can now access the entire keyboard, rather than just the keys.
- 4). Remove each faulty key. Start with the ones you suspect of having faulty key weights. Lift the back of the key to dislodge it from the key assembly.
- 5). Bang the key against the palm of your hand. If the key weight is really loose, it will slip out of the key. If not, prize it out with a screwdriver.
- 6). Use a Stanley knife to score a cross-hatch pattern on the top of the key weight. Apply a thin layer of silicone-rubber glue to the top of the key weight. The scored surface will bond better with the glue. Slot the key weight back into the key and fit the key inside a small bench-vise. Apply moderate pressure to the weight so that the glue sets it in place.
- 7). Remove the keys you suspect of being faulty. Spray contact cleaner onto a clean cloth and rub the cloth into the key contact strip underneath the key. Dirt may interrupt the contact between the key and the contact strip, causing a partial signal to be received rather than a full one.
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