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At my wits end!

rtkDarling

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I'm hooking up a Pyro f4:


With an AKK mini:



And I've blown two of them. The FC has TWO huge caps on it, the AKK is rated to 6s and I'm running it on 5s. Everything worked fine on the bench, when I punch it the VTX is toast. I have no idea what's causing this, any advice would be very appreciated. I know @RENOV8R, @HighTechPauper and @Futuramille are WAY better builders than I am. I'm hoping you guys have some ideas because I'm stumped. TIA
 

HighTechPauper

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I still think it could just be infant mortality on cheap and low QC on Chinese built electronics, but if I had to venture a guess it would be to add a small cap across the VBat/ground pads that the vTX is attached to, it could also be something like Futura is suspecting on his Skoll that the FC may be letting voltage out on the video out pad.

What 2 big caps do you have across the FC? And usually the caps are across the battery pigtail connection, or possibly on the DC input to the ESC's if they are individuals instead of a 4in1. If it is a 4in1, I would suggest only 1 1000 microfarad 35v cap instead of 2 caps. Where are your caps located? Got a pic?
 

rtkDarling

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The caps are on both ends of the pigtails; one at the xt60 and one at the board

So now I'm thinking it's a voltage spike issue because my camera got blown too. I found a spare VTX from my HGLRC batman that says it's rated to 26 volts and so far it's stood up. I have a scrap camera powered off of that instead of the FC and it's worked. I was able to punch it hard enough to get the FC to reset causing a crash, but everything still works... strange indeed. Just for now I'm putting a throttle limit on it to see if that keeps me from spiking it too hard. I'll probably end up taking the whole thing apart because I can't trust it, and I won't ride a horse I don't trust
 

rtkDarling

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Yep, that's all she wrote. I checked everything again, no shorts. Flies fine until you punch it or invert and it dies. The FC resets in the air, crashed of course, and blew a third VTX. So if we're counting (and I am) that's 3 VTX, 1 micro eagle, and the stack = almost $200 in parts I've burned on this rig.
Good times
 

Futuramille

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Oh man RTK, I feel your pain. like Hightech said, my FC blew 3 Runcam swift 2 cameras before I realized what was happening. I still can't prove it was voltage through the signal wire.. just know all three cams have the same tiny chip melted and it's in line with the signal wire. oscilloscope is the only way to possibly detect it and well.. I'll never own one of those so..
new cameras, new FC.
If not for the love of flying 😖☹😤

Good luck getting it all put back straight buddy!
 

rtkDarling

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I decided to double down instead of whimper out. I bought the exact same stack again but this time with a RushTank VTX. I figure if it does EXACTLY the same thing I can bet that it's a motor. Just got the whole thing soldered up and setup in BF / blHeli 32 and we'll see how she fares tomorrow.

I can be bummed that my build didn't work, or I can be grateful that I have the money and the knowledge to carry on. This has been a good reminder to appreciate what I have instead of perseverating on my failures.

FLY ON!
 

rtkDarling

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Had it all set up last night. Test hovered it, everything was fine for this morning. I wake up, and it's broken. Motor 4 stutters and won't spin up, and ESC #3 won't come up in Bl Heli

Screen Shot 2020-01-13 at 11.51.57 AM.png

I figure it was a short in the wires in motor 4 causing the stutter so I change it out to a spare I had and it does the same thing!!!!!

Now I have 1 motor that won't spin up, and 1 ESC that I can't configure. I'm praying someone here can help me.
 
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rtkDarling

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Another update: I flashed back to 3.5.7 and ESC#3 came back up. BLheli says all four have the same firmware and I verified them all. Motor 4 still stutters. I've tried 2 motors and resoldering the connections but nothing works. You can also hear that the final two tones crackle on the startup. Not sure what to try from here
 
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Futuramille

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I hate to say it but that sounds like a bad 4in1. you might want to run a little test and put a good motors signal wire from the flight Controller to the 4 in 1 stuttering motor if you can (if it's not a plug between the two) just to make sure its not the FC. that's about all I can think of RTK. This is sounding pain filled but Chin up.. It will fly!
 

rtkDarling

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Since this was the second stack that I haven't been able to get going I had another FC. That one brought the ESC up (running 4.0 instead) and gave me the idea to flash back to 3.5.7. Both FCs exhibit the stutter. I've changed the wire to motor 4 on the harness, reflashed the ESCs, tried different Dshots... I think I've covered it all, and I think you're correct : it's toast.

It's funny that I'm caught between feeling like I need to slow down and give it some space, and feeling like I have to "get back on the horse" and simply not give up until I make it fly. Randy knows that I take this stuff just a little too personally, and this particular build has been downright existential. It's made me realize that I'm relying too heavily on one thing, and that FPV can't be my only source for mining dopamine.

My name is Ryan, and I'm an FPV addict.🙃
 

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