As Prof. Farnsworth from Futurama would say, GOOD NEWS EVERYONE!! It lives! Lifted out a leg of C2523,
Powered on and ALL the buttons that were not working, are now working!!!!
All four channels on,
All channel buttons on,
Channel 3 (previously not working)
so to recap, I am now able to Select channel 3, select AC coupling channel 1 and 2, Scope BW, down buttons for Mode, trigger mode, source and CPLG, Slope, 5v for channel 3, Clear Display and Voltmeter.
I do plan on replacing C2523 but I want to ask an opinion on a different "issue". After the scope has been pn for about a minute, it develops a high squeal. Not terribly loud (to me at least) but noticeable. I have experience working with arcade CRT chassis and that squeal usually indicates a faulty flyback. Is it worth pursuing repairing that or just live with it considering I won't be using this scope 24/7.
I can't thank you guys enough for the guidance and patience. Now, does anyone here know anything about troublshooting an Asteroids PCB