1. Identify the downed keys:
- Locate the keys that are completely pressed down and unable to return to their normal position.
2. Check for broken or stuck parts:
- Inspect the keys and the mechanism beneath them for any visible signs of damage or obstructions that may be preventing them from moving freely.
3. Fix or replace broken parts:
- If you find any broken parts, such as springs or levers, you may need to replace them. Make sure to use the correct parts designed specifically for your Hallet & Davis player piano.
4. Clean the keys and mechanism:
- Using a soft cloth, carefully clean the keys and the mechanism beneath them to remove any dust, dirt, or debris that may be causing issues with their movement.
5. Lubricate the mechanism:
- Apply a small amount of piano key lubricant to the moving parts of the key mechanism to ensure smooth operation. Be careful not to over-lubricate, as this can also cause problems.
6. Adjust the key height:
- If necessary, adjust the height of the downed keys so that they are level with the other keys. This can usually be done by turning a small screw or adjustment knob located beneath the key.
7. Test the keys:
- Once you have made the necessary repairs and adjustments, test the keys to ensure that they are now functioning properly. Play each key and observe if they return to their normal position after being pressed.
8. Seek professional help:
- If you are unsure about how to proceed with any of these steps or if the problem persists, it is best to seek the assistance of a qualified piano technician who specializes in player pianos.
Remember that working on a player piano mechanism can be delicate and complex. If you are not confident in your ability to perform the repairs, it is advisable to consult with a professional to avoid causing further damage to the instrument.