New to audiokarma here, and late to the game with preamp repair, but your post has been incredibly helpful. I am currently in the middle of my own C-70 repair. I've gone through with deoxit several times, replaced the power supply caps, got rid of all the old Sony glue, and lubed the troublesome solinoid switcher (though it seems to work just fine). The one catch is that the right channel is weak/nearly non existent when I hook it up to my M-70. I know it's the C-70 with the issue because both channels work perfectly when i hook up my C-50. I'm going to go through and recap the C-70 completely to see if that fixes anything. In the mean time, any tips I should try to figure out why the right channel might be out or ideas on how to fix it? Willing to try anything to bring this C-70 back to life.