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Reversed polarity into Megasquirt II V3.
Posted: Tue Dec 27, 2011 7:33 am
by tomsmooth
Hello i was doing some on-bench testing earlier and i accidently reversed the polarity into the megasquirt for about a minute and i seem to have cooked something. Is there a protection for this? If not how much stuff will need replacing?
Thanks.
Re: Reversed polarity into Megasquirt II V3.
Posted: Tue Dec 27, 2011 11:43 am
by Bernard Fife
ts,
In theory, D9, D12, and D19 will all be flowing a lot of current if the polarity is accidentally reversed. They will burn out eventually though, and it's hard to say what would go next (though I recall that others that have done this may have had to replace the LED transistors Q6, Q7, and Q8 as well as possibly the fuel pump transistor Q19).
If this was mine, I would pull-up one leg of each of the three diodes (D9, D12, D19), and then test with a stim (and a power supply that won't fry anything on its own) to see if you are getting 5V at the voltage regulator, and if you have any communications with the processor.
Lance.