What colour wire should be going to pin8?Up until those last two measurements I thought that your 170V supply was basically working, but now it looks like the transistors have been blown and we are just seeing enough current leakage with no load to develop voltage across the zener diodes. I think we need to measure it with some load on it.
With the power off unplug the bottom section of the CN6 connector on the sound card (it goes on pins 1 to 4). This will remove all power from the sound board as that may have been damaged by the original problem. Reconnect CN5, making sure the alignment is right then power up and immediately measure the voltage between the screw head and pin 8 of CN5 again and see what it is. If more than 170V then switch off immediately, otherwise you can recheck the other voltages on CN5 like you did earlier to make sure they are still in the range I specified and see whether you have any displays and whether any of the game works before turning off and reporting back.