need mosfet data

Recently here, bought a rail of mosfets for $0.35 a piece.  These are 
in the TO-247 high power package and are evidently 400v devices or 
greater since they don't explode when plugged into my resonant coil 
driver  :) :)

Part # is APT4065BN and the logo on the chip is a large white square 
with a lightening bolt (black) through it.  I believe that Mitsubishi 
or Matsushita has recently changed their logo, so it might be one of 

In any case, it was the deal of the century since mosfets in this 
package are generally rated for 30A and above and usually cost $20-30

They each have a datecode of 8834 (34'th week of 1988) and with my 
exhaustive literature here still cannot find them.

Thanks, Rob.