That trickle diode thing was from Apple long ago to known repair shops at the time (late 1980s) as they were getting back too many "defective" IIcx PSUs. They figured it out and then sent the info to "us" techs and we all went along like nothing happened.

I wonder that Apple did with the 4 PSUs from my IIcx? They died from massive power surges that were from electrical fires in my building, several floors below me during the late 80s / early 90s. The PSUs gave themselves up to save the rest of the system.