Faulty PCB

[Maverickmax]

Hi

I recently built my own PCB board and I suspected it was faulty due to high current consumption when powering it with 5V. Now I want to test my faulty blank PCB board with a multimeter and a power supply unit in order to iron any short-circuited on the PCB board. Unfortunately I cannot remember how to to do but I vaguely recalled that I have done it the past as I applied a low current to the PCB and I tested it with my multimeter to measure the low voltage. If the voltage drops down to virtually zero in the region, I assumed the short-ciruited potentially was somewhere in that region. Is that correc method?

Regards

MM

 

[Sceadwian]

Why not use a multi meter on continuity mode?

 

[Maverickmax]

True but I have multi-layer PCB (4 layers - 24V, 15V and 5V). Both 24V and 15V are ok but 5V is giving me a problem as the current is rather high about 1.5A. Normally I expect it to be at least 400mA. So I thought it would be best to apply a very low current, say about 200mA and measure the voltage in the 5V circuit. I assumed the voltage drop to virtually zero which indicates a short-circuit. Is that correct?

MM

 

[Sceadwian]

Depends on the trace length, and degree of conduction between the shorted traces especially with fine traces. A better way to check for shorts I would think is to apply your current to the trace you're testing and then use a meter to test the voltage on other traces relative to ground, if there's no voltage getting to that trace then it should read 0 voltage relative to ground but it'll read a much higher positive voltage depending on the type of short. With that many layers tracing problems is near impossible.