I have two Uster Tester ( this machine used at textile) cards. one is corrupted and the other is the same one that works. Trying to repair the corrupted card by performing comparison test. When I try to make continuity test with the multimeter to the Vcc and GND terminals of the integrated cards on the robust card, only a short beep sounds heared and stops. however, when I test the continuity between Vcc and GND of any integrated circuit on the corrupted card, the beep sounds continuously. as far as I think it has been shorted somewhere in a capacitor. I wonder how quickly I can find this short-circuit element on the circuit
Electronic – How to find the short circuit element on electronic board easily
capacitormultimeterrepairshort-circuit
Best Answer
One method I have used is to allow current to flow from a power supply and then search for hot spots on the board using a thermal imaging camera.
So, you use a current limited power supply connected to VCC. Adjust the current and voltage so a substantial amount of power is flowing into the board. Maybe 100mW or so at first. Use a thermal imaging camera to find hot spots. If nothing sticks out, then allow more power. Maybe 250 mW, then 500 mW, then 1W until you see a hot spot. 1W should be more than enough.
If you don't have a thermal imaging camera, apply rubbing alcohol to the PCB before connecting the power supply. Then, after you apply power, watch for the spot that dries up most quickly. That is the hot spot. (I have never tried the alcohol method, but I hear it works).
Another option is to pull up the schematic and start removing components from the PCB that are connected to VCC. After each component, re-check the impedance. When you remove the faulty component (assuming there is only one component) the impedance will be high again.