If I was to guess by the looks of it that extra wire was to fix a broken trace and the repairman was just too lazy or did not have front snipers to get rid of the wire if it was me I would cut the wire off by the solder and forgot about it. As far as the slam tilt modification, everything you need to know is in the repair doc already in this thread this is the direct link to that section http://www.pinrepair.com/sys1/#slam

And it cannot be re-iterated enough I would rebuild the connectors before trouble shooting any board issues.