Picked up a 30amp supply. Knew had at least 1 problem. Output was double voltage, showed 24volts. Figured 1 of the voltage regulators was bad and would be an easy fix. Sure enough, 1 of the 7 regs. was bad. Replaced. Delighted to find normal output voltage in the 12v range but when tested under load the voltage dropped down to around 2 volts. Any idea what to check next?