I have some basic knowledge about electronics. I am trying to repair an ATX 250W power supply.
In the picture below, I measured 0V with my DMM between points C and D (AC inputs of diode bridge rectifier.) I was expecting 220V AC.
Measuring with the DMM set to "diode," the bridge rectifier entries give me this:
- FC = 0.5
- FD = 0.5
- EC = 0.5
- ED = 0.5
These measurements lead me believe that the bridge is OK. Why is there then 0V between the AC inputs?
Measuring the capacitors with DMM set to "capacitor" gives me the right values (off by about 5% or so.)
When measuring the capacitors with the DMM set to resistance 200M, I get 1. I was expecting the value to rise as they charge but since they are 2.2nF (orange) and 4.7nF (yellow), I suppose they may be charging fast.
The voltage between points A and B is 220V AC (Since A and C are the same point, is this mean C and D are shorted ).
Does anyone have an idea what could be wrong these observations?
The image below shows the wiring of the components in the power supply.