PSU burns and dameges only my DIY pedal

[JackSkellington]

Hello guys.
A friend of mine find out that its Mooer PSU didn't work after two months of inactivity.
I noticed that my DIY Tremulus Lune pedal in its pedalboard has both the IC faulty, after I changed both the pedal sounds ok. Other pedals in the pedalboard, Boss, Electro Harmonix and Fulltone was ok.
Why just my DIY pedal is broken?

I admit my DIY pedal had no protection diodes in line to the 9v or across the ground (even I usually include at least one).
I don't know what exactly happened to the PSU, I can say that the LED doesn't turn on and the two poles of the plug (italy plug) "seems" shorted (the multimeter beep breifly), and they measure about 100R of resistance. Anyway it doesn't supply the 9v.
Do you think a diode in my pedal would have saved it?