It's a 12si (I think) 140 amp single wire alternator (from summit) in my dually with a 455 in it. I hooked the negative cable to the positive post, and touched the positive cable to the negative post. Big spark and now no charging. My first thought was to take it to the local rebuilder, but is there anything I can do to fix it?
you mighta fried a fuse link...pretty sure the wire from the alt goes to the starters big top lug, no? If so, test the fuse link at the starter end of the alt wire.
I did that once on a $200 '76 Riviera; it melted the fuseable link by the starter. I found it but didn't fix it. I moved away and left it. Patrick
No fuseable link here, it's a large wire (about as big as a sharpie marker) going straight from the battery to the alternator. Cranked it up and moved it after my oops, so I "think" the alternator is the only problem. I turned the key on, took note of the voltage, started the truck and revved it some to get the alternator to kick in, but the voltage never changed.
It'd be worth at least asking around for a rebuilder willing (and capable) to try it. Between agriculture and law enforcement there should be some old school shops who aren't afraid of cracking it open for a lookey see. Patrick
There's a place here that can fix it, I just wondered if anyone else had done the same thing and knew what got fried. I swapped the alternator from the Dinosoar and it works just fine on the truck, so the truck is OK, the alternator, not so much!
You zorched some diodes, for sure. That is an easy fix. Any decent alternator shop should be able to fix you up without selling you an entire rebuild, if it isn't all that old (why only replace diodes in an alternator that has 100k miles on it, for instance?). Don't know for sure what you have, but some parts stores actually carry diodes/diode trios that you can buy separately.
Probably fried a diode or the diode trio. You can buy a $50 alternator at Advance usually these have all new components except for the case and the rotor and stator. Alos kits are available like this one ww.ebay.com/itm/like/190616712246?lpid=82 which would have everything the Advance alternator has. Almost not really worth taking apart anymore.
I figured I'd tear into it and try to learn a little. Going to school cost money, right? :dollar: :laugh: The original diode pack has 70amp diodes in it, the one I bought has 25amp diodes. With the new one in hand, I checked it with my meter, then checked the old one again about the time the display started fading (battery going out!). Another meter, recheck everything, and both diode packs check OK. Figures. Put the new unit in and back on the truck, rev it up a little and it starts charging. Sometime soon I'm going to put the 70amp diodes back in and see what happens. At least I've learned a little about alternators! :idea2:
I did the same thing. After taking the battery out to swap a new one I THEN, realize both cables to the battery were red. So I did what you did, and then saw smoke. It was the fusible links. One or two. No damage other than swapping them out.
