Clock will only strike once on the hour -- Trend Movement 124BL

My clock has worked wonderfully for 30 plus years. We have periodically changed it from Strike to Silent because guests are not used to it chiming in the middle of the night.

After a recent guest, we moved the clock back to strike. It goes through all the chimes every 15 minutes, but on the hour, it only strikes once, instead of the number of strikes it should for that hour (i.e. 10 times on 10 o'clock).

The third weight (one on the left) descends but not at the same rate as the other two weights -- suspect this is because it is only chiming once each hour.

Downloaded the Sligh Instruction and Care Manual but didn't find any help there.

Any ideas???

Thanks -- deadrok1942@gmail.com