I am using arduino mega with LCD 4X20 character to measure weight by 40 kg load cell and pt 100 to measure the temp. I have 4 output to 4 relay module. all are powered from 12vdc /3 amp Power supply.. the problem is.. the display started normally showing every thing perfectly.. but when the output comes out and the loads runs.. random characters appear is the power supply is not enough? or another problem.. Please advice.