There are many sections on feedback. You have to read all sections and follow all links (reading the linked pages top to bottom). There's no way to cover every aspect of every possible circuit in any tutorial. You have to read (until it's clear) all sections and see how they apply to the amp you're repairing.
In this amp, the BD_OUT is the feedback. It gets back to the servo/feedback op-amp via R316.
In this amp, the BD_OUT is the feedback. It gets back to the servo/feedback op-amp via R316.
Read the page on op-amps (online if you don't have the tutorial).
You can have any voltage (as far as the op-amp can swing) with 0.000v on both inputs. the op-amp drives (in a circuit with local feedback) the output to make the inverting input match the non-inverting input. There is a bit of error so they may not match exactly but they will be close.
This amp is like a huge op-amp. The feedback and the drive signal drive pin 2 of U301. All of the components after pin 1 of U301 are essentially in the feedback loop.
You can have any voltage (as far as the op-amp can swing) with 0.000v on both inputs. the op-amp drives (in a circuit with local feedback) the output to make the inverting input match the non-inverting input. There is a bit of error so they may not match exactly but they will be close.
This amp is like a huge op-amp. The feedback and the drive signal drive pin 2 of U301. All of the components after pin 1 of U301 are essentially in the feedback loop.
Perry,
This morning I tried a different approach. I kept the hv disconnected and applied a 60hz signal into the rca input and traced input to pin 2 of the u301. At this point I believe my feedback loop is not broken and for some reason I cannot get both drive signals to from both opamps to operate simultaneously without some sort of input signal. Pin 1 had a small sine wave from audio and the output had a nice square wave on pin 7 of U301 and u302.
This morning I tried a different approach. I kept the hv disconnected and applied a 60hz signal into the rca input and traced input to pin 2 of the u301. At this point I believe my feedback loop is not broken and for some reason I cannot get both drive signals to from both opamps to operate simultaneously without some sort of input signal. Pin 1 had a small sine wave from audio and the output had a nice square wave on pin 7 of U301 and u302.
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