I'm not 100% certain but I believe I attached the positive cable first. That's the sequence I usually use because I'd always heard the ground should be attached last.
That is the procedure I was taught too. The thing is that (and now we get a little theoretical) since the cars ride on insulating rubber tires, they can get charged with static electricity. That means that two cars can have very different electrical potential which is really an excess of electrons in one of the cars. That happens to helicopters, for instance, and jets fueling in air. They need to neutralize the potential difference before any jet fuel is involved or you can get a nice fireball in the sky.
The difference can be several thousand volts but the energy level is small so the little spark that occurs when that difference is leveled out contains very little energy and can often not be seen in daylight. Jets and helicopters are in a different league.
Anyway, when the plus terminal is connected first, (half of) the excess electrons that are present in one of the cars rush over to the other car to equalize the potential. They take whatever way they can find to ground (minus) and the current can be significant although brief. Quite enough to fry a diode and pop a resistor.
Opening up a wide and straight connection from plus to ground is the way to eliminate this problem.
Or equalizing any potential difference first by connecting the grounds briefly before beginning the actual jump start procedure.
I'm a little surprised MSD haven't protected their gear better but these things are tricky and a re-design is costly. It should be a warranty repair, though, if it falls under normal use, which I would say jump starting does.
