Very cool Tuukka . I'd like to understand this a little better so I grabbed the schematic:
Gulfstream rectifier short (resized).jpg
If I understand correctly one of the rectifier diodes has shorted so that it conducts presumably in both directions rather than the single direction it is intended to. If the red diode for example were shorted then the rectified DC output voltage on the -J- or jumper wire would short to the AC input voltage on the -RED- wire and eventually find its way back into the 24 volt secondary transformer winding. The extra DC current apparently isn't enough to blow the 15 amp fuse on the 24 volt circuit.

The steady DC current flowing through the 24 volt secondary winding would create a constant magnetic field in the transformer core that would combine with the normal alternating magnetic field created by the 110 volt AC input current in the core. The combined magnetic fields saturate the transformer core at some point. A saturated core essentially means that the core cannot support any more magnetic field. Once the core is saturated any current applied to the core doesn't go towards increasing the magnetic field but instead gets wasted as heat.

Once the core saturates the input 110 volt current isn't doing the work of creating more magnetic field. Does that make the saturated transformer core look to the 110 volt supply like a lower resistance (or actually lower impedance) load which draws more current which in turn blows the 110 volt 10 amp fuse?

/Mark

There is a great online circuit simulator that can demonstrate this better than I can explain it but here are two screen shots:
Rectifier simulation (resized).jpg
On the left is a simplified version of the rectifier circuit with a 60 Hz voltage source representing the transformer and a 100 ohm resistor representing the various coils (e.g. pop bumpers) using the DC supply. Along the bottom you can see that the current through the voltage source is less than an amp and the voltage across the load is fully rectified. (Ignore the 1 ohm resistor on the bottom which was added to avoid a dead short in the simulation.)

On the right side the lower right diode of the rectifier is replaced by a wire to represent the short. In this case the circuit looks like the original circuit half of the time. But the other half of the time all of the current flows through the upper right diode of the rectifier, then down through the short on the lower right and back out to the voltage source. No voltage is generated on the output so the DC is only half rectified. The current through the voltage source is measured in amps, not in milliamps.

To see these animations and experiment with the circuit try these links:

Normal rectifier: https://tinyurl.com/y84jb78b
Damaged rectifier: https://tinyurl.com/y7kbqljs

Then click on the Run/Stop button in the upper right to start or stop the animation.

BTW, I wonder if the topic title could be revised to make the shorted rectifier discussion easier to find in the future.