MSefi.com read only forum (Jan.15,2018)

I built my MS-II a few years back but tnever got it to work right after I finished assembling it it wouldn't connect to save my life. I know for a fact that C11 is not installed but near as I can tell that should not affect the serial communication. I checked the voltages on the CPU soket and they are a little low at 4.25 on all 1, 20, and 31. What should be my next step I would really like to figure out what is going on so I can run this in my car and any help would be greatly appreciated.

Remove the CPU, check the voltage going in to the regulator.

It checks the same on the socket as it does on the reg itself. I think I may have something grounded out on the stim it has a constant IG light.

What main board is this? It sounds like there's a partial short somewhere - or an inadequate power supply feeding your Stim.

It's a V3 board. I can't figure out for the life of me what is causing this short I assume it is something in the ignition circuit but everything appears OK. I shouldn't have let it sit on my shelf so long I can't remember what I did and didn't do. Any pointers on potential points of failure? The stim is powered by a 12v wall adapter at 200mA.

Disconnect MS from the stim, does the stim have good voltage at all points?
Disconnect as much as possible from MS and check all voltages.

To check for a short in the Megasquirt PCB, power up the Megasquirt on a Stimulator or on the car and check the following points for voltage with a multimeter.

You should find the same voltage as the battery voltage on the following points: S12, S12C, the center legs of Q9 and Q12, the left (non-banded) end of D3, the left leg of U5, and the left (banded) end of D9.

You should have 5 volts at the following points: S5, the two +5V holes in the proto area, the right (non-banded) end of D9, the right leg of U5, the left (banded) end of D19, and pins 1, 20, and 31 of the CPU.

Let me know where you find the correct voltages, and where you find the wrong ones.