he tried to fix the IDE connections again by soldering

This is living very dangerously.

Rob Schofield, the authorized empeg repair person, had this to say about soldering on the IDE header.

I would look upon that advice as being worthy of respect.

Before you go too far in exploring what might be wrong with the player, do as Tony suggested and either swap your hard drive into a known good player, or try the hard drive from a known good player in your unit, and see where the problem travels.

tanstaafl.