The 1968 Cherokee 180 D that I fly has developed a persistant oscillation in the ammeter which is being evaluated and everything is pointing towards the master switch failing. On this model, the master is not "split" into battery and alternator, rather is one full size rocker switch. Anyone have experience replacing a single master with a split? Even if this turns out not to be the problem, I am considering such an upgrade since it will extend the life of the alternator.