Tuna Posted May 1, 2020 Share Posted May 1, 2020 I have another post going but just curious if there is anyway to tell if a motherboard is bad? I want to order a new one but they are sold as is. So I want to make sure mine is bad before ordering another one. I'm trying to let the capacitors discharge now before I need to much with it. Quote Link to comment Share on other sites More sharing options...
yuweng Posted May 2, 2020 Share Posted May 2, 2020 fried my friend's mobo last month, still waiting for the ic chips from China, shipping via sea is like taking forever since all flight suspended Mistake i made was just like you, discharge using the on/ off switch then start working on the mobo, i think i accidentally shorted one of the chip, there are still high voltage on those capacitors ! Remember i saw it either here or youtube video, after disconnected the battery, off/on a few times to discharge, they still shorted both the huge capacitor to fully discharge it & one comment says its a bad practice so i didn't do it & fully regreted it. Troubleshoot & found the culprit, its was the regulator AMS1117 shorted but that one is the 3.3v supply rail connected to all including the STM32, MPU6050 & etc chips. So i went on checking all chips & found one of the ACS709 was the actual culprit, it has a few more pins shorted to ground. For you case, first measure the AMS1117 with a multimeter, if its shorted, it won't switch on. On your board, i think AMS1117 is at the RED circle area. Quote Link to comment Share on other sites More sharing options...
Tuna Posted May 2, 2020 Author Share Posted May 2, 2020 Thanks yuweng for the detailed walkthrough! I'll meet with it more today and see what I can find out. I went ahead and ordered another motherboard just in case. I don't really trust myself trying to replace components on a board but I'll definitely try 1 Quote Link to comment Share on other sites More sharing options...
mrelwood Posted May 3, 2020 Share Posted May 3, 2020 The caps don’t get flushed with a few quick presses, we had a multimeter on a Nikola board while we did that and it took about half a minute of keeping the power button pressed to get below 20V. 1 Quote Link to comment Share on other sites More sharing options...
Tuna Posted May 3, 2020 Author Share Posted May 3, 2020 Yeah I had to hold mine down for a long time to to get mine too discharge Quote Link to comment Share on other sites More sharing options...
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