Your chime melody is too fast or too slow.
If it's too slow, the most common cause is that the movement is in need of an overhaul. The oil in the movement is starting to get gummed up and instead of lubricating the gear train, it's adding drag. Take your clock to a qualified repairperson.
If it's too fast, it may be that the governor fan which regulates the speed of the chime gear train has become loose on its shaft. A qualified repairperson should be able to tighten this. Do not attempt to affix the fan to the shaft with any kind of adhesive or solder! These fans are designed to slip a little -- yours is just slipping too much.
Prestige Clock Repair
Bluff Heights (near 4th and Junipero)
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