Upon reviewing the Apple II PLUS power supply schematics --on the whole is a very simple SMPS (Switch Mode Power Supply). Being a design engineer (Microprocessor designer) and designed some complex SMPS myself (20KW and 50 KW).
Wirh my background knowledge... I am POSITIVELY STUMPED by the two components on the schematics. First loock at the bottom of the schematic you'll find C8 and a transistor labelled AR1* and a warning icon next to it (triangle with a !).
Okay, I see it as an NPN with the C8 electrolytic capacitor connecting its base to the emitter connection... And get this, NO DC bias connection to the base?! So with any thorough knowledge, this transistor is ALWAYS off. But, I did notice the transistor is labelled AR1*. That must mean something.
Question to anyone here with good knowledge of this design. How will AR1 ever turn on. And how does this circuit work??!!
Purplexed in Portland.