I'm a bit puzzled.  Just purchased a JTV-69 last weekend (had to drive 250 miles to find a stocking dealer, but that's a rant for another time).  The guitar has only two tension springs installed on the tremolo mechanism.  All the photos I've seen here show (3) springs.  Tuning stability is only so-so, even after checking for piezo-pickup cable rub and other obvious issues that have been beaten to death here.  For other JTV-69 owners:  How many springs did your instrument come with?