The MPX-100 is a 5-tube unit consisting of 1-12AT7, 1-6AB4, 1-6AU6, 1-ECH84 and 1-12AX7.
Thanks Larry, Thought I got lucky, mine is 47991E.KlankTank: The SAMS manual you reference with alignment instructions is for the 10001-19999 series (check the serial on the back face). The 20001-29999 and 40001-49999 series are different. Do not use if your's is a 20001-29999 or 40001-49999 series.