I agree, the 7100 power supplies look a bit more complex in circuitry. The 100's are usually straight forward although I did a repair yesterday that was not the regular 2 capacitors but a capacitor that looked fine in the switching circuitry.. The PSU-B's are actually pretty straight forward usually as well although again they don't usually have bulging capacitors like the 100.
I have 1 7100 supply here that actually blew a power resistor and blew it again when I replaced that so it's something further down the line I guess but nothing obvious.