Two Akai S612 Sampler and two MD280 Quickdisk Drive. On both units the quickdisk wasn't working, disc did not load. I expected the belt were worn out and it was. I ordered new belts and that solved the problem. I also noticed that the pots and sliders were dirty, so I cleaned these (desolder,open,clean...). I also replaced the tactiles. On one unit it was fun to change the LEDs (and the resistors) to blue. Usually I don´t really like the blue LEDs but in this case it looked pretty amazing. Still need a blue 7-segment for this. Could't find the right replacement for this until now. If someone knows, please let me know. Both Akai S612 Sampler tested ok. Quickdisc is loading. Like always I share my knowledge and pictures with you.