ender 3 V2: experiencing low voltage (~6v) at fans and printer not working. im thinking a short circut but i dont know how to diagnose properly.

recently replaced thermistor with a thermocouple (part of my dragon hot end upgrade) and also had to 12V fans running in series off the 24V circuit. was running fine during initial tests then the fans just cut off and started wining a bit. replaced everything to stock and still have the same problem.

tested voltage at fans and it is very low (~6V).

did I fry something?