Today I started to try to fix my old A-126 by just replace some suspected components.
Because the Shift and Mix and Up-Down outputs do not work properly at all; for you just hear some changes in sound, when turning the knobs. I mean you do not hear up and down sounds at the same time. And it also does not go/sound from down to up and vice versa.
And you do not hear any mix sounds at the Mix output.
And the Up and Down outputs sound the same.

I started to replace IC 5 (TL064) .
And now you can hear the sound goes from down to up (up-shifting part), but no down-shifting sound to hear.
And the Up and Down outputs still sound the same.

And now I do not know which components I should replace next.
Is there somebody who please can give me a hint, for I do can solder very well, so I won't dissapoint you.