Can you do something else? Shut down the amp and let the caps bleed out.Then set your meter to ohms and measure between the ground and both sides of R40, one side should be zero ohms, the other side should be 220k ohm.
Tried this, and I get no movement on the meter, for either side. Once I turn on both switches though, I'm still getting roughly 249v across R40.
Q8/R31/D24/D23 and R34 form a 1mA reference current. This should give around 180V over R35, try measuring over R35. Also keep both power leads out of the amplifier boards (both of them) when measuring, as this could affect readings if one of the amps are duff.
So I measured across R35, with both switches on, and I'm only getting .0010v.
Tried these measurements with both of my DMM's
Not sure if it's related, but my power switch also seems to be a little wonky. After flipping the power on, sometimes the amp will go off, and I'll need to flip it a couple times. Sometimes it will go off, after I flip the standby switch off. Almost seems like a bad switch.