Hammer of an upright piano has loose the 'flange screw'.

[themaximillyan]

Hammer of an upright piano has loose the 'flange screw'. (A4) key has a lot of play. How fix it DIY.

The hammer of the upright piano has loose the 'flange screw'. The (A4) key has weird sound there. How fix it DIY. Need take the right kind of screwdriver to got the 'flange screw' tightened up there only.
Here's how to fix it: 
1 Open the topmost cover of your upright piano (top board) or (front cover).
 2 Remove the upper front board, which is fixed in place with two spiners.
 3 Lift up the keyboard cover (fallboard).
 4 Place the sting of the screwdriver into 'the flange screw' ( in the 'action' the upright piano) and turn it clockwise to tightened up.If you scoot the jack to the side, you’ll see the hammer flange screw. Tighten it (without repositioning the hammer, hold the hammer/flange in place with your fingers while you tighten the screw) and you’re good-to-go.
 Note: Proceed with caution if attempting to fix it yourself. One more requirement. When you have inserted the screwdriver blade into the screw slot, try not to damage the 'whippen jack' (A4) which is located here too. The "whippen jack" should be gently moved aside with the screwdriver before turning the 'flange screw' clockwise.
 I also forgot to mention the need for additional lighting, as the 'flange' is located under the upright piano hammer and there is poor lighting there. It is important to have good lighting when repairing the piano flange. Using an additional lamp or flashlight is recommended to see clearly under the hammers and to avoid any potential damage to the upright piano or injuries. Safety and accuracy are important aspects when performing fix. If you did all right there than the weird sound (A4) get off there. good lucks,