takeshi666 wrote:
Maybe it's a loose cap or some other component?
That's a very good possibility as well if the issue is not related to an alignment problem. That's why it's important to open up the player and fiddle around to see what location is affected by the whack. Cold solder joints is a good possibility as well considering the complicated nature of an M series player (the more wiring one has, the more that can go wrong over time).