I am doing some action photography this weekend, specifically a ski race and my winder 2 is DOA.
I have not used the winder in months, the batteries are stored separately from the unit and they are fine. It's just not firing period, either with my OM-1md and OM-2n. The contacts for the battery and to the camera show no corrosion at all.
So worth cracking open to see what's wrong?
I'd recommend cleaning the contacts for the body-winder interconnection. That might be the problem.
But my history with W2s have been pretty similar. I had two die but an ancient Winder-1 has been indestructable. It looks horrid, though. The W1s were much more reliable.
I have taken apart the winders, and even merged two W2s together to get one to work. It can be done, but there are a couple mystery clasps and screws that hold it together which I've never been able to negotiate properly.
It's unfortunate you didn't find this earlier, I could have sent you my W1--it's no longer in use since I acquired a pair of MD2s.
I really have to get that timing thing down.