Bad alternator? or the death of my car?
 

98 Mazda protege LX. 200K miles.

At a stoplight, turned off the car during long idle. Wouldnt restart, as if the battery died. Had it jumped by AAA. Drove a few miles, the airbag light began blinking, and then the car died. Battery is strong. Charged it and replaced battery cables just in case. When I went to jump it, heard a fizzling sound and saw smoke from under the left front dash area (smoke exited from under the hood).

I was going to install a new alternator, but now I'm wondering if its something else. Turns over, but the electrical short (or whatever it is) fizzles as I crank.

oldeng, where are you?:(

Update: Replaced the alternator....tried to crank, same smoke. Hooked up to another car, gunned their engine, and mine started and has been running well this afternoon. I'm dying to know where the smoke came from....it came out from the hole where the driver-side wiper arm is......however, it hasnt smoked since the battery has been recharged...

I'm here.
It's NOT the alternator! An alternator produces no output unless it's spinning at a fair rate. What I suspect is a major grounding deficiency such that the return current from the starter motor is not following the route intended for it and is "improvising a workaround path" back to the battery negative via some other path which includes stuff never intended to carry hundreds of amps.
Look where your battery negative cable attaches to the chassis via a grounding plate with three bolts on it, one of which attaches the end of the negative battery cable, one of which attached the grounding plate to the chassis where the front suspension tower is, and a third which retains a thing having a grey plastic cover over a bunch of small black wires coming out and going all over the place (this is the main ground fanning strip). Start by disconnecting the battery negative terminal, then unbolt all three of those grounding plate bolts and using a brass bristled wire brush and WD40 spray, give that grounding plate and its associated hardware a through cleanup, both top and bottom; then thoroughly clean the chassis area and bolt hole at the grounding plate attachment. You will notice that at the end of the battery negative cable, the termination lug has another fat wire crimped into it, its insulation is black, possibly with a yellow stripe and it snakes its way under the battery mounting plate and out of sight. You have to make sure that the crimped termination where it's spliced with the negative battery cable is really solid and also cleaned up. Use a pair of vice grips if you have to to squeeze and consolidate that connection. Reassemble the main grounding plate, enduring that all bolts are secure.
Now you have to trace the other end of the ground cable sharing the battery negative crimped lug which disappears underneath the battery mounting tray and ensure that it hasn't been broken and that it is clean and securely connected to (I think) the transmission housing near or at the starter motor mounting. (I think a defect with this cable may be the source of your problem).
While you're at it, check that the starter motor mounting bolts are clean and secure too.
Finally, go over to the passenger side and check that your alternator mounting bolts are tight, and check out the engine block ground lug on top of the engine mount.
With a charged battery you can now give things a try.

After I posted this, another thought occurred to me. You can do a check on the ground return being the culprit by using a battery booster cable to bypass that suspect ground cable. If I'm right, connecting the booster cable between the negative battery terminal at one end and a big bare metal piece of hardware bolted onto the transmission housing close to the starter motor (on the starter motor is best, but usually not possible). This will provide a safe return path for the starter current and stop the pyrotechnics. Using a booster cable as a substitute ground for bonding the battery -ve, the block to chassis, block to battery negative etc. etc. is a quick safe and handy way to bypass suspect grounding/ bonding wiring. Just don't mess up and inadvertently use it to test your battery cranking amp. capacity by getting the battery +ve into the act by mistake (you can WELD the jaws of the booster cable to your car that way!!)