Sorry I got to your discussion too late. I have someone in Toronto who can fix your card in the future. And I can supply you with Mosfets. I had to replace or repair traction card last month. Dealer wanted $5000 and I got it fixed for $2200. Mosfets they asked $2000 each I can sell them for $860. I do not think you can get FM400TU-2A. I've been told its obsolete. So you will have to go with higher unit like FM600. Guy who fixed the card said they mostly go in pairs because to create rotating magnetic field you need two phases energized.

Brumbear, Ray & the factory are pointing you in the correct direction. Controller is Meidensha (Japan) and best avenue for support is through Komatsu or one of it's local dealers (Ray works for a Komatsu dealer)

Thanks Ray I did get to a fet problem however Komatsu factory said replace all the fets or your on your own. So until I know more about these AC drive units I pulled the entire AC unit and am having the factory do it. I can not seem to find anyone who rebuilds the AC units. I guess they are proprietary and not similar enough

Side note,also know that an e-45 code can be caused by a shorted f.e.t module as well.

Left side of the unit,door will swing down.once open remove the cover over the controller,there will be two cards exposed..traction and lift.The card are labeled so you know which is which.Be careful as thye plugs have small wires and are easily damaged if not removed correctly.

Ok I got the code description I have to replace traction cpu PCB anyone know where it is?