Well, in the sch you provided (there is something missing at the very bottom, but I think it is GND), the sole connection to the case shown is the 1M resistor R31, which is used to bring the case and the GND under the same potential.
Unless I am missing something.
Of course there is a cap across that R31. And it could be bad. Or, again, we are missing something.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Interesting readings, r31 common ground to case bounced to 1meg on analog meter, r31 common to case bounced to 1meg. R31=1meg. Across c7, which is common to case with a parallel resistor = 40k ohms steady.