That was probably mine,
The 4300's serial #'s that end with a C and beyond can use the same SMPS as the 4600. (Dual mosfet version)
The B and lower use the single mosfet SMPS version. The entire lower card area (stepped down case) is about 1/2" lower in height than the 4600. (B and lower)
What I don't know is whether the 4300 and C versions use the higher volatge HVPS (34.9K) of the 4600.
My B version has the 34K HVPS only.
Everything would be the same as a 4600 except the HVPS voltage and the focus coils (weaker magnets on the 4300 labeled PT# KNF28 vs KOH23 on the 4600)
The menus are different somewhat, The 2 critical temp readings are both displayed onscreen on the 4600 Code-39-code
The 4300 (B) displays the temp in one of the pages instead of onscreen
The main differences picture wise between them are increase focus ability and peak brightness swings of the 4600 vs the 4300, but both are essentially cut from the same cloth
David
David