'82 JCM 800 4104 Service and Mods

[physics]

Yet another project start(ed/ing).... Picked up a 1982 Marshall 4104 loaded with two EV Force 12's (heatsinked, and with the computer style fonts on the back cover and dustcap) in my new place since all my other gear is several hundred miles away still. Seller said the shop that biased it claims it needs a cap job soon, I just got a minimum set of tools in the mail from my old place so I'll be checking the caps for value, filtration, seal burst, etc. I have a replacement set on hand if needed, and now that I have my tools I should be able to do the job myself. Most recently, it stopped making noise. Knobs have no effect, including the master. Powers on fine, fuses are correct values and are not blown. Hopefully this weekend I'll be able to check voltages and trace the signal.