I doubt if anything can be done, but I thought I'd throw this out there... my Panasonic VHS/DVD recorder (DMR-EZ48V) has a recording lens that's just about had it. For the past few months it would only record to DVD+RW discs, but now the recordings fail to record perhaps once every three times. I do realize that age is a factor here (I've had it for about five years), but is the recording lens repairable in any way, either at home or at a shop? Either way I'll probably be buying a new recordable combo unit soon, but I thought I'd ask just in case.
FWIW, there's nothing wrong with the VHS side (being that it doesn't get used often, and I've rarely used it for VHS to DVD conversion, surprisingly), and the DVD side can still read silver discs without a problem. The worst case scenario is that it goes from a VHS/DVD recorder to a VHS/DVD player, which is nothing to complain about. It's akin to that joke Mitch Hedberg made... an escalator can never break, it can only become stairs.