In most cases, something has broken or come unglued and is easily fixed.
SHAPIRO PIANO SERVICE will not sell an old grand with old strings and pins as these pianos won't hold tune anymore and must be rebuilt every 40 years or so in order to be used and serviced. Rebuilding should be performed by experienced re-builders, as special adjustments are critical to the final tone and performance of the instrument.
Rebuilding is not inexpensive because it takes sometimes as long as three months to correctly complete the process. Be cautious of the re-builder who sells his work cheap as they probably do cheap work and skip the proper procedures to insure a quality finished product.
We at SHAPIRO PIANO SERVICE have rebuilt hundreds of pianos.