You’re braver than me, best of luck with this.
You might ask, cover off: why? power switch gone, why? didn’t bother to put the cover back on or put the screws in a bag at least, why?
I would be inclined to ship it to the maker, have them check it out, put back a proper power switch, provide the correct screws. Think about potential resale.
My Chase Line Controllers, no power switch, turns on/off by it’s remote, however it needs to be fully unplugged to get back to defaults, because it retains any adjustments you make, I drill holes in the front and add toggle switches to do that.
Yours has dual transformers, so cut into one leg of the power cord inside, before it goes anywhere else, put the switch in-line, back to where you cut the wire, .
https://www.amazon.com/dp/B0BVB9D27N?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_4
If you add your own power switch, I noticed it draws 800 watts
Of course you could put a line switch in the cord where you can easily reach it.
Specifications Output power per channel 120W into 8Ω, 200W into 4Ω Output impedance <0.03Ω Line inputs 1V for 120W into 8Ω XLR inputs 2V for 120W into 8Ω Input impedance 11kΩ Frequency response <10Hz – 100kHz, -3dB THD <0.08% Signal-to-noise, line -100dB Power consumption 800W Dimensions (WxDxH) 430 x 385 x 100mm Weight 16kg
btw
"It can internally be configured as a fully balanced mono power amplifier using either balanced (XLR) or unbalanced (RCA) inputs. In this mode the A30.2 is capable of delivering 1 x 380W into an 8ohm load."
maybe this is why it was opened up, you never know.
here's to luck!

