Thank you for such a valuable answer! I am not a wizard of electronics and still learning a lot of things; comparing the foil side with upper side of PCB is really fascinating! I was trying to derust iron chains at that time so current consumption didn't really matter at that setup!
I have a computer PSU of Microsmart(cheap Chinese electronics company) having model no. MSP-450W. I was using the power supply as my lab bench power supply to power up my electrolysis setup. I accidentally shorted the 12VDC Yellow wire to Black ground wire. Before I could realize what I did...