Just got two solar lanterns that need more serious attention: The built in battery compartments have disintegrated. The original AA batteries were 600mh but you can now get AAA cells with 1200mh so I've got some wire ended AAA battery holders that can be fitted inside the original spaces and secured with some sticky foam pads.
Can't remember how old these are but I've had them a long long time so could easily be 25 years old. The electronics are all discrete on a small PCB.
Worth fixing as they're so superior to anything on sale today.