have you the schem ?
edit : it look like this
i don’t know if it’s important but it seems you use 1N4148 diodes instead of 1N4001
here’s a verified version
it seem to be exactely the same.
I think that your problem don’t come from the layout stripboard.
btw i don’t really understand your colors indications
10uf must be connected in line E and F (you put a blue on D )
all your blue and greem marks, it’s for me all the trigger circuit, not sound
sorry if i not understand 