Here’s some pictures I took of my Leslie 122 RV. From reading up on this model I understand that these usually come with a Leslie-designed reverb amp which is not deemed all that desirable, but this one actually has a Hammond AO-44-1 reverb amp in it, the very same as is found in the A-100 series. I think it sounds great, even through the small speaker that is mounted on the side of the cabinet.
Here is the full schematic of the Leslie 122 amplifier.
More information on servicing the Lelie 122 amp can be found at How to service a Leslie 122 amp