Now that said, thankfully there is a resource; a facility that does perform such repairs, even on the obsolete components. Contact Mark and M&M Electronics. They are located in Ohio. Here’s their website:
He’ll probably tell you the same thing; to upgrade to the new Xantrex TrueCharge2 battery charger, but at least it’s worth a phone call to find out. It might be worth it to have him, at least diagnose the problem with your 40+.