Hello everyone, my first post and day on AK! I did some searching around and no luck on what I need to ask! My question is my selector switch works on A, but not on B only if I slightly turn it towards the A+B position but where it does not click in the A+B position. This is a 1991 SD model amp (120V North American) the part # is ASD1004 (S401) for (SD type Pioneer A-676). Are these switches a bit mechanical where one can try to align (if there are metal parts within) it so the B channel will work? I only had one pair to test each channel, and is it possible that the A+B will work (I should have tested it) on its own even though the B position was off a bit? The relay does click in the: Off/A/B/A+B. The amp sustained a bit of a mishap where the Phono selector switch was pushed into the amp...it clicks fine but I do not use Phono so I am not too worried on that right now. Any help/knowledge share if the switch is replaceable with a good quality one or do I need the exact model? I did email Pioneer to ask for the part, I was not sure if the A-717 switch might work. I thank you all in advance for the help and look forward to learning and gaining some new friends on AK!