I have a williams system 4 sound card with two transitor reset circuit and replaced transistors with 3904s. The 6.8volt zener works 12volt unreg is 12.6volts the supply voltages on collector 4.89 volts but Q1 collector to emitter voltage 2.4volts causing output voltage to cpu reset to be 2.4volts instead of 4.xvolts to get a high on 6802 pin 40 reset.

I checked all resistor values as specified , new 3904s bjts,
zener diode drop is the specified 6.8 volts ,unreg supply measures 12.6 volts .

Cant figure out why Q1 collector voltage isnt over 4 volts stuck at 2.4 volts??

Maybe one of the transistors is not biased correctly but biasing resistors in line with schematic values

IMG_20200515_003414 (resized).jpg

Hello I remove q1 q2 and resistors. I re oriented a
mcp130-xxDI as were many variations of that supervisor. held the reset high and seemed to work fine in the circuit and eliminated the tricky biasing of q1 and q2 and no need for zener diode or a few resistors in reset area.
great advice!!