У вашего броузера проблема в совместимости с HTML5
A little video I did of a repair on my Juno-Di, I got as a gift from a friend, all knobs were not working properly, so I disassembled everything, rebuilt all potentiometers and did a little tricky, as can be seeing in some pictures, I've cutted the side metal parts to do a more resistant tabs to hold .
Now it's working wonderfully!