I had a problem with missing speech on my High Speed which re-appeared after I had pressed on some of the chips in the sound section of the CPU. All sounds were working correctly before this.
The sounds then all worked fine for a couple of games before I noticed an unrelated issue of the kickback not working - diagnosed to a faulty Q7. I took the CPU board out to replace Q7 and also the pre-driver Q5, and then the correct pre-driver Q3 due to the schematics being wrong
After re-fitting the CPU board I have no sounds at all. At one point I could hear the music play very faintly through the speaker with the volume turned up fully in Music Test but this has now also disappeared.
I have checked previous post on similar problems but it makes for quite vague reading.
Could someone point me in the right direction with what I should be checking first?