Alright, I pluged the module exactly like the the 9-103-04, it worked , but it did not solved the problem.
I found this thread by DHR4683 :
http://videokarma.org/showthread.php?t=265234
That last gasp CCII has the 9-103-04A board (the A is listed has a replacement part for the 9-103-04 in the schematics glued on in inside of the cabinet!), but what I find strange is that the board in this one is not wired the same as mine...shouldn't those board be wired exacly the same in order to work? Maybe mine was tempered with?
Edit : I really have the impression that the volume slider is the problem...could those wear so bad that cleaning could not work?
Thanks!