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mCP X Brushless Mods Blade Micro CPx Brushless Mods and Conversions


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Old 08-19-2014, 04:17 PM   #1 (permalink)
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Default Burnt FET on Oversky 10A Esc?

Hi all you heli-geniuses. I have been thoroughly enjoying my brushless mcpx. It's been a lot of fun but also much more work for me so far. Anyway, I noticed a few weeks ago that the motor seems much weaker and it bogs a lot easier and the 7mm tail does not hold nearly as well anymore. I ordered some new 7mm tails from Astroid-Designs and put them on and still had the same problem. My flight times dropped back down to around 2 mins again too from 3:15. I learned how to do spectral analysis for reducing vibes and that has been much better, but that didn't do much to solve the problem. I finally took it all apart and cleaned everything up nicely. While I was inspecting the esc, I noticed one of the main motor fets looked slightly powdery-whitish on the side with only 1 leg. It looks slightly different from the other two. I suspect that I burned/harmed the fet in a crash. I do recall it smelling "warm" (that's best way I can describe it) for a while.

In any case, everything else looks clean and the connections all seem solid. Does it look like a burnt fet in the included picture, and would a burnt fet be causing the symptoms of reduced flight times, reduced power/increased bogging, and tail blow out?
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Old 08-19-2014, 04:49 PM   #2 (permalink)
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That's not a fet, they are on the other side of the board (and much bigger), that's a fet driver, and if it was fried one phase of the esc wouldn't work, so the motor wouldn't run at all.

Hard to say what might be causing the issues, glad to take a look at it again for you though
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Old 08-19-2014, 06:08 PM   #3 (permalink)
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Shows how much I know

I'll keep messing with it. I noticed that the negative lead from the esc to the battery has a frayed wire so I'll see if trimming and resoldering that doesn't help. I also noticed a tiny crack in the heat shrink for the motor wires right where they bend around the board to the esc. I wonder if one of the wires was damaged in a crash?

I also noticed that my arb has a slight fracture so I ordered up a deleting on from you. There were only the 4mm ones. I figured that would be ok.
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Old 08-21-2014, 02:48 PM   #4 (permalink)
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Quote:
Originally Posted by sethy79 View Post
Shows how much I know

I'll keep messing with it. I noticed that the negative lead from the esc to the battery has a frayed wire so I'll see if trimming and resoldering that doesn't help. I also noticed a tiny crack in the heat shrink for the motor wires right where they bend around the board to the esc. I wonder if one of the wires was damaged in a crash?

I also noticed that my arb has a slight fracture so I ordered up a deleting on from you. There were only the 4mm ones. I figured that would be ok.
The 4mm shorter ARB doesn't work unless you shorten the main shaft but I sent you a stock length one anyways

Hopefully it's an issue with the wiring, but I have a feeling a new esc is in your future...
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Old 08-21-2014, 03:12 PM   #5 (permalink)
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Dylan, you are a mind reader. I couldn't select the normal version on your website, so I just did the 4mm and hoped for the best. I know. I'm an awesome customer

I took everything apart and cleaned it all up and oiled things nicely. I reflowed all of the joints (messing up your beautiful solder job, but hey I had to try). I put new blades and a new main gear on too. Results are about the same, but I haven't taken care of the vibes yet, so we will see about that.

Anyway, I was hoping you would say I needed a new esc. I picked up v1 board for a decent price and I've had my eye on an xp-7a and an hp05s and have been trying to convince myself not to buy them. You don't happen to have any do you? I'd much rather buy from you than elsewhere if possible.
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Old 08-21-2014, 03:26 PM   #6 (permalink)
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Quote:
Originally Posted by sethy79 View Post
Dylan, you are a mind reader. I couldn't select the normal version on your website, so I just did the 4mm and hoped for the best. I know. I'm an awesome customer

I took everything apart and cleaned it all up and oiled things nicely. I reflowed all of the joints (messing up your beautiful solder job, but hey I had to try). I put new blades and a new main gear on too. Results are about the same, but I haven't taken care of the vibes yet, so we will see about that.

Anyway, I was hoping you would say I needed a new esc. I picked up v1 board for a decent price and I've had my eye on an xp-7a and an hp05s and have been trying to convince myself not to buy them. You don't happen to have any do you? I'd much rather buy from you than elsewhere if possible.
Shoot me an email, I have lots of slightly used stuff I can make you a good deal on
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Old 09-13-2014, 03:31 PM   #7 (permalink)
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Im experiencing the same thing on my double bl mcpx. Uses 2x mx3a escs, one with stacked fets, 12000kv main m5, 12000kv tail.

Power has dropped suddenly a while ago, tail blows out, and flight times are about 2-3 minutes on 500mah lipos, 1:30-2 min on 300. All batteries do the same, so its safe to say its not them, plus they are 7 mobths old with not many cycles. Voltage at the end of flight is as high as 3.8v, but pretty much just falls to the ground if I try to keep flying.
Motors are not hot, esc lukewarm at most.
Solderings fine. Used to fly 4-5 minutes before with lots more power.
Is it possible that and esc is part damaged and draws too much current? Or a motor to have a short, and yet still run smooth?
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