Repairing an industrial beacon (with schematic)

These beacons are commonly mounted on industrial equipment to indicate that a process has finished or a problem has occurred.
They are available in 12V, 24V, 36V, and 220VAC versions and a range of colours including red, yellow, green and blue. (The 220V version seems fine on 110V to 240V.)

I bought a 12V and 220V unit to compare them, and it turns out they use a common PCB.

I'd guess the 24V and 36V units probably use a resistor to limit the current to the 12V Zener.
The 220V version is the most versatile since it can be adapted to any voltage and also made into a static light by bridging the transistor that flashes the LEDs.

These units are very low power at less than one watt.

The keywords to find these are:-
"industrial warning beacon"
There are different types, and the typical price is around $6 plus shipping.

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