Check ac voltage one probe on pin 1 and other on pin 4 and have none? Transformer could be bad, but would be extremely rare. Most likely wiring problem or bad coin door switch.

Try reseating the output connector(s) at the back of the transformer.

It’s nearly never the transformer.

Make sure you have these plugged in.
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J123 and J131 should be empty (these are keyed the same as J106)

Unlikely, but a break in the transformer secondary winding would cause the issue you're seeing. With the power off, check for continuity on the white/ red wires at the transformer output connector. While you have the connector apart, look for pushed or worn pins on both sides of the connector.

Regarding the ruptured C11, see here: https://pinwiki.com/wiki/index.php?title=Williams_WPC#Exploding_or_Damaged_15.2C000uf_Capacitor_at_C11_.28C10_on_WPC-95.29

and also this from Clay's repair guide:

Exploding +20 volt Capacitor.
There are cases when the +20 volt capacitor (Driver board C11 on WPC-S and prior, C10 on WPC-95) can just explode. This happens when a shorted flipper coil diode or shorted transistor on the Fliptronics board causes the 70 volt coil power to feedback into the 20 volt flashlamp circuitry. Because of reverse voltage, this blows the 20 volt capacitor. Also installing one of the ribbon cable connectors in the backbox on the header pins (top row of header pins to bottom row of housing) can do the same thing. And lastly, if connector J124 is mistakenly plugged into the driver board connector J128 (they are keyed alike!), this can cause capacitor C11 to explode.

First check the ribbon cable header pins to make sure they are attached correctly. Then check the flippers. If when the flippers are activated, one of the flashlamps dimly lights, there may be a bad flipper transistor on the Fliptronics board.

There is a preventive measure which can be taken for this. Install a blocking diode on the driver board ceramic 10 watt resistor R224 (or R9 on WPC-95). To do this, first remove the lower leg of resistor resistor R224 (the leg just above TP7). Connect the anode (non-banded end) of a 1N4004 (or 1N4007) diode to the resistor's leg. Then solder the cathode (banded side) of the diode back into the driver board (where one leg of R224 was removed). This will prevent the problem.

Excellent advice!

This safety measure is implemented in my reproduction WPC-89 power board. One reason that new reproduction circuitry can be better than new re-manufacturing of the original Williams circuitry.

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Seems obvious, but since no one mentioned it, don't forget to check the interlock switch as the AC voltage for the flashers from the transformer goes through the coin door interlock switch. You can always back probe the connector across the two WHT-RED wires on the connector coming from transformer to see if you have voltage there.
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You can also completely bypass the interlock switch and its wiring by connecting the PDB directly to the transformer secondary's by making the connection shown below:
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Correct, with the exception of GI lighting the transformer winding are NOT bonded to ground anywhere so there is no difference between holding the second meter lead on ground than there would be holding it in open air when making the measurement.

Assuming the replacement Bridge was had the same specs as the original, I would lean more towards a broken connection point over a second failed Bridge Rectifier.