Autotek MM 4000.1

I just got 2 more of theese amps..

Both amps do the same thing..

I just replaced all of the outputs in both amps also rebuilt the driverboards in both amps..

On the driverboards i replaced both Driver IC'S the tl072,LM211,LM293 and replaced all the surface mpunt transistors..

If i put both driverboards in the amp it will protect and not even attempt to power up..

If i stick only 1 driverboard in the amp it will power up green and idle perfectly

All of the regulators in the amp are also brand new..

All regulated voltages are correct and i have both + - rail voltages


Any ideas what to check?