I had an issues with the alternator overcharging the battery on my way back home from a trip. In an attempt to make it home I tried unplugging the battery and try to drive the car. It didn't work and the car immediately shut off.

I tried restarting and MS would not power on anymore. I checked the fuses and replaced the 80amp main in the engine bay. After that MS wont come on. I grounded the fuel pump to make sure that it works and it does. So it's definitely MS. I have the unit off the car, how can I diagnose if the board is fried? Thanks

 

What main board version do you have?

 

MSV30
BG

That's what is written on it.

 

That's the chip etching. See this link for how to ID the MegaSquirt:

http://www.msextra.com/doc/general/whatmegasquirt.html

 

Looks like a 3.0 pcb

 

he has a v3.0 board MS1 that I built him back in like 2007.

can you tell if any diodes or capacitors look fried? specifically the large yellow ones near the serial port.

 

They do not seem to be fried

 

I tested the diodes with a multimeter and they all seem fine. Any other ideas? I need to have my car running asap

 

Did you check all the fuses in the cabin? The "Engine" controls the main relay and fuel pump relay.

 

Yeah they all were fine. Although, I'll double check them later tomorrow again.

 

I checked the fuses again today just to be sure and they're all fine.

Also, for an instant I plugged in MS and it lit up. However, when I tried again I got no signal from it and the LEDs went dead again.