your symptoms are identicall to what went wrong when some one jumped my car and they put the terminals on backwards...
fried my alternator...
but if you say alt. is fine, i would start by checking all the fuses, and grounds.
do a search for the grounds:
http://www.cygnusx1.net/Supra/Librar...2/default.aspx
in my case i just replaced alt. and everything was fine.
did you check to make sure it was the correct battery??
also try posting @
www.celicasupra.com
there isnt many mk2 people here and i blow @ wiring.