[Steve Davis]

Morzh, most 70s you find will be early models. You can tell an early from a late model by looking at the back of the chassis. The early model will have three IF adjustment trimmers on the left side near the tube shield, with one having a metal cover over it. The late model will have four trimmers, with the first and third having covers. The model 90 was built in three versions. The mid and late versions had AVC, only the early did not. You can also tell these at glance, the early version has a toggle switch marked normal/distant just to the left of the speaker connector. The mid and late versions do not have this switch. You can also tell a mid from a late version by counting the ganges of the tuning condenser, the late version only has three, the other two have four.

Steve