Spring breakage repetition

judging by the question, you would be better off waiting for the tuner; perhaps if needed, have them do a tuning or just a quick 'touch-up'. If you can wait until the radiators are turned on, it's better!

That said, if you don't already know how to do it: the first thing to do is learn how to remove the action from a grand piano. If you are not a hands-on person, there is a risk of breaking the hammer repetitions because to remove it, you have to take it from the side; therefore, it would be good practice to have observed your technician removing the action at least a couple of times. After that, knowing the risk of causing minor damage, there shouldn't be any problems!

p.s. removing the supports is not exactly an easy task; often, simply by removing the action, small problems can be resolved. In any case, everyone is free to do what they believe with their own instrument, at least to understand what is wrong!

I agree with Andry. Unless you have practice extracting the action. If so, you can reach the back of the action and unscrew the bracket, taking care to first disassemble the bar that carries the hammer braking felt (where the wippens must not rest, but be about two or three mm away). Once the bracket is disassembled, you can see if: the spring is broken (unlikely), if the cap to which it is attached is broken (if it is a standard spring), or if it has simply come unhooked (if it is a Hertz-type spring). If it seems complicated to you, a good technician in your area will solve the problem.

Many thanks for the timely and exhaustive answers.

I managed to remove the stand and found that the loop has broken; putting an intact loop back seems like an impossible task to me, any tips?

you can try with a drop of superglue. Let it dry well and then reattach the spring. or glue a loop of silk cord using superglue.

I'll try...

Thanks a thousand times again for the precious advice.