I will ask questions about the power supply sequence of OP177.
Originally it should start up ± power at the same time, but the negative side is the rising earlier by the circumstances of the other of ICs.
So, after the rise of the negative power supply, do it power on the positive side is allowed up to how much of the delay.
In general, it countermeasures using the clamp diode. But, since the substrate modification is not in time, it must accommodate to change the sequence.
In addition, it using the ± 15V supplies.
At that time, what the positive side, if how much the impedance of the positive power of when that is to off.