Use proper working unit to give proper pattern readouts to speed trouble solving of defect in same circuit of second unit needing repairs.
Suppose correctly working unit circuit is top circuit.
Second unit with problem circuit is bottom circuit with added 50 ohm resistor to simulate component defect.
Notice how groups of components have " signature" when A.C. powered and shown on oscilloscope X-Y mode. When patterns are not the same check component by component in found problem area to pinpoint out of tolerance parts.
