Sorry to resurrect an old topic, but this thread did help me.
Just got the last of the SG Special robots from Sam Ash ($799, WOW fire sale), while the store had charged it the night before I picked it up (it showed an almost full charge), when I went to charge it, I got the flashing green peg, and red solid charger situation with a 3ft cord.
I switched to a foot pedal inline coupler (solid, no cable), and it worked correctly. As I didn't want that much solid connections hanging off the bottom of the guitar's jack: I then cleaned the Guitar's and charger's jack with a pipe cleaner (nylon bristle type, not fuzzy) with some contact cleaner on it. Now I can use up to a 6 foot cord with no problems.
Next...I tackle the intonation procedure.
