I own a FT-901DM for years and although I've the owners and service manual from the time it was issued in dead tree's pulp, and tried to accompany the developments in the documentation of this radio at Fox Tango, all the ancillary documents like the "survivals guide" etc. I never managed to obtain a schematic of the PA stage for the "SD" version of this radios, which according to sales brochures and the aforementioned manuals is a simpler version which an output of 10 W.

Is there available a schematic of the PA stage for this version of the radio?

Alternatively is there still some more detailed description of such stage?

I wonder because for ten watts output it would not make sense (to me) that the 12BY7 + two 6146s be retained in the PA stage, however I cannot find any additional information on what did the engineers at Yaesu created almost fifty years ago?

TIA and 73 de PY2CSH