Do-Re-Mi-Boom!.

A man falls in love with a piano player and tries to woo her. A passerby hears a maid's music, fancies he's found his true love, and chats her up. Her boyfriend arrives for his music lesson and jealously dismisses the interloper, who swipes a grinder's organ (and monkey) to help him serenade the maid. Later he follows the boyfriend to a residence hotel and plants a bomb in the man's piano. The organ-grinder is gunning for the thief, and soon the piano, bomb, monkey, thief, and pistol-packing grinder are rolling down the road to the delight of maid and lover. It's ka-boom for some and a kiss for others.