Hi again,
Tron:
Im afraid that picture is a little too blurry, maybe you could try to get a better pic. Alternately you could read the number off of that chip at the upper left corner of the picture and we might find a data sheet on it.
Little Ghostman:
Sure no problem. I included a diagram that shows what to look for.
The cap is driven by a frequency generator and a resistor, but you could use a 555 timer chip with approximately 50 percent duty cycle output and a resistor in series with the output.
Normally it takes a cap a little while to charge up with a voltage source and resistor in series, but when there is ESR the ESR allows the voltage to 'jump' up or down suddenly without taking any time because the resistance part is not reactive. This shows up in the voltage wave on the scope as shown in the attachment. The voltage due to the capacitance ramps up or down while the voltage due to the ESR shoots up or down without any ramping. Knowing the current and change in voltage we can calculate the ESR, but high ESR shows up as a large, quick change, and when compared to a 'good' cap the difference is quite obvious so we dont even have to calculate anything if we have a good cap laying around we can compare it to.
Also, i may have forgotten to mention that when testing the power supply out of the case without a motherboard, a load resistor is required. I was able to get mine up and running with a 10 ohm load from the 3.3v supply to ground. Yours might need 5 ohms or perhaps a load on the 5v supply. Without that it might shut down right away just like that.