HP-41C with 23A batteries - remedy possible?

[Jonas Sandstedt]

Hello, I recently bought a HP 41C calculator, and as stated in the heading I inserted wrong batteries, type 23A instead of type N, such that the circuits were fed 48V instead of 6V. Not good, of course, and now the calculator is dead when fed with proper voltage. Looking at the schematics it seems as if at least the power supply circuit U2 could have been damaged, but could other circuits have been damaged too? I have measured the protective diodes and the transistors Q1+Q2, and they seem OK. I wonder if this has happened to anyone before that has been able to restore the calculator afterwards.
best regards Jonas