I just had a look online, and unfortunately there are a fair number of SOT-23 devices that match up with a "BR" code. Some of them appear to be diodes, as well, to add to the overall confusion.
Ya, I got so into looking for them that one said PNP and others say NPN, lmao... The code book is a BIG ball of stress, lmao. Thanks for trying. 🙂
Transistor marked BR - likely - 2SC2412K
https://www.s-manuals.com/pdf/datasheet/2/s/2sc1740s,_2sc2412k,_2sc4081,_2sc4617,_2sc5658_rohm.pdf
https://www.s-manuals.com/pdf/datasheet/2/s/2sc1740s,_2sc2412k,_2sc4081,_2sc4617,_2sc5658_rohm.pdf
I think so. Short across the thermistor to trigger the protection circuit. Does it drive pin 4 high enough to shut down the PS driver IC?
I'd have to put the card back in to verify... I'll just scoop some originals up from Digikey. Thanks Perry.
So just a,community heads up... when I bought the 2SC2412Ks from Digikey... they have BQ written on them, not BR.
The R is the HFE value. The 2SC2412KT146R is likely what you intended to order. They have a wide overlap on HFE. The ones you have should work.