The way I fried my BPPC card.

[Castellen]

If you really want to see what the power supply is doing, don't use a multimeter, as it gives you an AVERAGE reading.
I.E. it might say 4.9V which should be fine, but there might be ripple as low as 4.2V which will definately cause problems.

The correct way to measure the stability of a power supply is to use a decent oscilloscope, or some recording multimeters can capture fast peaks/dropouts.


Sounds like you've helped the BPPC board by giving it a more stable supply.  The components which blew up are probably tantalum capacitors.
They have a very low ESR (series resistance) which makes them good at smoothing power supply noise, but means when they charge up as the system is turned on, the current flow can be many 10s of amperes.  Occasionally this causes the tantalum dielectric to break down, the device short circuits, then if the current flow is great enough, it explodes.
I've seen it quite a bit, mainly with leaded components rather than SMD ones.

The additional resistance of the motherboard power tracks would have helped to limit the inrush current to the capacitors, so made the dielectric less likely to break down.
Often they can handle high inrush current, but it would seem you had the unfortunate luck of one failing.  It happens...
 

[Castellen]

@ Chunder:
Yes, they can be replaced.  Anything is potentially repairable.

@PiR:
To the casual observer, many SMD components can look the same.  Despite working in the professional electronics industry, I sometimes get small inductors, resistors and certain capacitors mixed up.  Sometimes there is very little physical differences.

The huge capacitor idea would not really serve as an over voltage protection.  Like if you accidentally put 12V instad of 5V onto the thing, you'll still get 12V across your equipment, but it make take an additional 100ms or so to rise to 12V.
It may serve to smooth power supply ripple to some extent, but you would want a capacitor with low series resistance for this.  Ideally you need a number of capacitors in parallel on the power supply line.

Do remember that the multimeter gives a rough indication only, and may even lead you down the wrong path.  I've seen many trainee technicians make the same mistake all too often.  After spending hours chasing themselves around in circles, they eventually use the advice of using a scope for critical voltage measurement, which shows exactly what's happening.
You can either make assumptions and guesses, or you can find out exactly what's happening and do something about it.