Thank you very much! You're legend! It looks similarly to my amp which I assumed now it is rather correct. Just like I mentioned it is different than M506, 509, 508 where the needle falls slowly without any response to music signal. The signals are removed immediately after the switching off and then the needle nicley and slowly falls to zero. In 507 the signals should also be disconnected from the meter circuit but the muting circuit is puling the output of the meter to the ground so it falls much fast anyway. Onkyo made this circuit much more complicated compering to the next in Integra series from that time but this part of the design is not the greatest one. I like the meter response though.