It sounds like a wiring problem similar to the one you just fixed.
 
The Sounds are triggering signals are sent from the cpu board 1J8 pins 8 to 12 and got to sound board 10J3 pins 2 to 5 and 7 so check those connection first

the wiring between the cpu and the sound board is listed below.

1J8             10J3
8        -         7    sound select 4
9        -         4    sound select 3
10      -         5    sound select 2
11      -         2    sound select 1
12      -         3    sound select 0

When you press the test on the sound board it should play some sounds followed by some words and loop back to the sounds and so on

check the wiring on the mentioned plugs, if all looks fine and you still have no sounds then you can check that all the sound inputs are working on the sound board by unpluging 10J3 on the sound board and using a wire with alligator clips on both ends.
clip one end of the wire to the bracket that the sound board is mounted to and with the other end ground each of the following pins one at a time, you should get a different sound from each pin. 10J3 pins 2, 3, 4, 5, 7
the other pins on 10J3 are not used.
you will not get every sound effect the the board can produce this way, to get all the sounds multiple pins are used together.

if you do not get a sound from each pin then there is a problem on the sound board. if you do then there is still a problem with the wiring between the 2 boards or a problem on the CPU board