Pin 7 - ground: 0.09 ohmI am still thinking pin 6 as well. I know you replaced Q4, and that things got a little better. But E, B, Pin 6 connected: 11.1V, 11.3V is not ok. I would expect to see 0.6-0.7V difference as you see on the good supply. Do you have another KSC2073, or try the SD313 again for Q4? And just to be sure grounding is ok, can you measure resistance between pin 7 and metal chassis, and pin 9 to metal chassis? This is really strange...
Pin 9 - ground: 0.09 ohm
Will remove q4 and put in new KSC2073TU...