the voltage got lost in between.
the current goes from the capacitors in front to the schottky diode in back through that mosfet up in the corner next to the M&M, and from the mosfet to the transformer with 48V on it. the M&M is called an ICL, inrush current limiter, and it has a value of 3 ohms and is 15mm in diameter from reading the label. it is a thermistor, a Negative Temperature Coefficient thermistor which slows the current rushing in when you power up. when it has current flowing through it the temperature rises and it gets really hot so that the resistance drops from 3ohms to almost nothing, so the voltage drop across the ICL is zero when it is still intact. if you had the full 120V there, we would know the ICL had blown open. make sense?
the current goes from the plus side of the caps through that high frequency switching mosfet into the transformer and back to ground on the input. ground in the input section, or front end, is the negative of those capacitors. it should say ground on the pcb right out in the middle. put your negative voltmeter probe on the input ground there, and measure the voltage on the three legs of the mosfet. looking at it from left to right, the legs are gate, drain, and source. the voltage on the source will be high since it is on the plus of the capacitors. the voltage on the gate will be lower by far, and the drain should be higher but less than the source, i would guess. so look for that.
take big pictures of the bottom where the traces are so we can look for open traces.
you need to look carefully at the traces and see if you can find a place where the traces to that transformer or the mosfet are cracked. they can be open with the tiniest of faint lines to indicate they are cracked, look to see if the heat sinks are soldered into the traces and the traces are broken close to that. sometimes the heat sinks hit something or twist the trace and the trace tears open near the soldered spot.
doesn't look like the current is being switched into the 48V transformer, or the leds would light up, imo.