Need some feed back on this one, I have this problematic machine that is giving me a headache. I have this mp 4002 that won't power on but the main power light will fire up but nothing on the display and no sound from the machine. After testing the power supply board with the multimeter I not notice I wasn't getting 24 volts at certain points so with that being said I went ahead and replaced the board but to no avail it didnt change a thing.