I've picked one of these up (Marantz Pm151) and reflowed a bucket load of dry joints l, now I want to set the bias but there's no information on this just a schematic with no indication on it, I take it that its measured over R723/4 but what to set it to?
Given its a small budget amp amp I would say bias would be on the low side, perhaps around 50ma as a max (so 5mv across each resistor, 10mv end to end). Check with no speaker attached because DC offset will skew the result.
