[R-390] R390 solid state supply

[SHELLY199 at aol.com]

Hello all list members.  Tks for the good reads about a subject that  is 
dear to my heart.
 
I have a lovely R389 which is truely in remarkable shape and has been  
restored to almost new condition.  I have been considering solid stating  the 
regulated power supply.  I have a PDF file that shows instructions on  how to 
install a solid state power supply mod that someone came up with and  sells 
somewhere.  Problem is I don't and can't find info on who makes the  board.  
Seems like a great mod in that no holes need to be drilled and a  lot of 
heat is removed from the circuitry.
 
Does anyone know of the source for this mod?
 
Tks,
Rich  wd2q