As nochtanseenspecht mentioned in the PSS thread, connecting pin 16 on the big chip to 11 on the small chip accesses some super low octaves played on the middle to high part of the keyboard. Also, if you connect pin 16 on the big chip to 10 on the small chip you get the opposite effect and can play very high octaves as well that are triggered by the lower keys on the board.
Here's a few more points. The letter A after a number stands for the large chip, and B stands for the small
33A, 3B and 33A, 4B. These both work well with the auto accompany feature playing, particularly if you play some individual notes. 33A, 4B also makes a constant tonal stuttering sound when connected.
1A, 28A. Functional but not too strange. When these two pins are connected, whatever notes are currently being played will hold indefinitely. Nice if you need a drone of a specific pitch, and it doesn't cause a crash. This bend occurs multiple places on the chip.
I'd be curious to hear what other people found.
What have other people found?