5 Volt Line Not Stable in LCD Monitor
I’m having trouble pinpointing the fault of a non powering LCD monitor, the +12V line checks good (stable 13V) But the +5V line gives me a non stable reading with a DMM, I’ve tried an analog meter and the needle waves rapidly. I’ve changed the Schottky diode and filtering caps but the problem persists. does it have anything to do with the transformer or I should look elsewhere, what do you advice?
Try break the 5 volt line to see if it still fluctuates. If still fluctuates then the problem is in the power supply- it could be bad filter cap, leaky output diode and etc. If after breaking the 5 volt line and the 5 volt is stable then probably ahead of the 5 volt line (usually mainboard) have some leaky component.