I had a Playmatic Big Town, with the same sound board. Your Chance sounds a bit different, kinda out of tune. Try replacing the 1 nF capacitor near the 4069 IC. Also the sound fading seems not working, so replace the 4.7 uF capacitor near 4007 IC. Since there are very large value resistors used, make sure the board is clean of dirt and dust.

Here is a sound board schematic for reference. The Ca1-Ca4 inputs select one the sounds (523 Hz, 659 Hz, 784 Hz, 988 Hz - musical notes C5, E5, G5, B6). Ca5 causes the sound to slowly fade out.

bt-sou (resized).png