Fixed, did a complete about face method contrary to every bit of advice out there and it works! Chain on smallest rear cog and front derailleur held wide by a block of wood next to the seat post and then a flat blade screwdriver inserted between the wood and derailleur so that the chain is perfectly on the largest chainring. Cable secured, remove wood and screwdriver, and repeat until derailleur does not move, after which it moved across all three chainrings without a problem