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Slavvy posted:I took it apart and ding ding it's the serial. What have you got connected to pin 30, Opto IN (+)? Because looking at that trace, it looks like that's actually what caused the short. Bad board or a bit of moisture and if you've got a high potential between pin 30 and that serial chip trace, that'll be the result.
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Oct 16, 2018 22:33
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Also thanks babyeatingpsychopath for making this thread. I've always wondered what an EFI conversion would look like.
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Oct 16, 2018 23:02
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Slavvy posted:Pin 30 doesn't go anywhere, the wire is a five inch stub that's heat shrinked and insulated on the end. No continuity between it and the burned trace either. The burned trace has continuity to connector pins 18, 20, 22 and 23. All of which are marked as various flavors of GND so I'm guessing that's good and normal? Hmm, must just be some heat damage/discoloration then. Have you got access to a megger? Just weird for me to see a burned trace like that without some external failure cause like moisture or a bent pin on the connector or something, unless it's a bad board. I don't tend to see the board level stuff though, more the external stuff, so burned circuit boards are only something I deal with after other people have done the forensic analysis and I've read the report.
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Oct 17, 2018 01:09
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Slavvy posted:Right, I've very carefully tested all of the above and these are my results: Yeah that second edit is my suspicion. That trace going pop, which is at ground/earth potential - logic 0 -, and no damage to anything else means that trace specifically has had 12v find its way to it, probably through a damaged or defective board. That damage may have been moisture exposure causing dendritic corrosion to start, which, once it's started will eventually find the low potential and cause a short. I may be wrong on that, but it's a likely and common enough fault. If you have a megger (Fluke 1587 is great if you can get one, crank types are fine though), I would find the nearest 12v source to that trace and megger between it (or probably just use pin 1) and pin 19 and see what sort of resistance you get. Should be megohms. If you're seeing 100s of kilohms or less, you're probably looking at a corroded path through the board to the trace. I wouldn't waste money getting a megger just to test this though. It's loving hosed m8, as they say, and really all you're left with is replacing the trace with a wire. You probably won't have to worry about further problems if it's a board fault because the trace is already toast and the damage is already done there. No more ground to short to, though I guess you could scrape out the trace remains so there's no high resistance path either.
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Oct 17, 2018 21:24
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