Hi, more help needed if possible …Just built two MK138s D1s failed on both as they where powered up, what did i do wrong? polarity was correct. edit I have several N4001 diodes from a power supply could the be used?
Either you used an AC voltage instead of a DC voltage to power the kit, or there is a dead short somewhere on your board (drawing more than 1A).
1N4001 is fine.