I have a pair of the hands model that is 15 months old. I have done no
modifications to it. The last time I used it several weeks ago, the
current was petty weak in both units despite having good batteries and
my having scoured the plates (that usually helps).

Tonight, I have no current in either of them. I replaced the
batteries, the plates, and the pads (all purchased from General Medical-
-not homemade plates and/or pads). It made no difference. What else
might it be? I know it is not just that I am used to the current
because I had my husband try it too. The power light is on, and the
wheel is at its highest setting.