I am very suspect of this one. First of all, it is an original Dyna St-400 chassis with a 416 faceplate. Nothing ever left our shop like this. I suspect the faceplate and "modified by Van Alstine" tag may have been transplanted from a different unit. The 416, and our Double 400 upgrade, both had chassis plugs on the side for an external power supply box. This unit does not. The Dyna 416 had a black painted chassis. Any Van Alstine identification on the rear of the heat sink is missing. Note that the power switch has been replaced - not by us. Photos of the insides and the output transistor array on the back of the heat sink would be helpful.
Regards,
Frank Van Alstine