[RHayden]

What type of timer is the xfrmr equipped with? Maybe a solar eye involved? Those are usually the 2 main problem items for us. Although we did have one xfrmr go completely out this summer. Try bypassing these items if you can and see if the lights remain on and the voltage stays constant.

If its not the timer or solar cell- or possibly the main power source- you'll wind up sending it in for repair which might not make sense if its an older unit. Might be just as cheap to replace with your preferred brand and have the warranty.

Start checking voltage at various points to isolate the problem. As always, be aware of the local codes as far as when you need a licensed electrician etc.....and remember, safety first.