Getting started on a Gay 90's after a long hiatus...
Even in 1970 I guess manufacturers were shaving costs. The back of the cabinet is particleboard and pretty chewed up at the bottom. One big chunk missing. Have a look:
What would you recommend as a repair? I believe the joint is just a 45° bevel, nothing fancy.
I'm thinking to heat the corners with a heat gun and hopefully tap the back out and replace with plywood.
Another option I think is to cut say the bottom 6" off the back and replace with plywood rather than removing the whole back.
Not sure whether resin repair is an option, considering the whole lip is gone and I don't think I'm going to be able to biscuit joint a strip of wood onto that particle board!