Enlighten me, masters. (Quad problem)

[TwoFourty]

Hello, long story short, i got a quad, which spins motor #1 significantly slower. I tried to detect problem. Swapped the motors, problem stayed in the same area. Put the motors back in place, got a new esc, put it in, motor #1 still spinning slower. I even swaped esc signal wires on FC but guess what, problem is still on #1 leg. Riddle me that, pls. Everything is calibrated each time before testing.

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[orfordness]

Does your quad have an integrated PDB? I';ve has just this happen and it was a fracture in the integrated power circuit in the bottom plate.

[TwoFourty]

OMG. Never thought about it. I use Matek PDB mounted under FC. And when i look back, i had a good crash before this happened. Definetly gonna check it tommorow.
Thanks for that, your kindness.

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[Cheredanine]

So you have this problem with motor 1 despite changing both the esc and the motor?

So there are a number of possibilities here-

1. Power supply being throttled, - regardless of what the FC commands if the power supplied to the esc is being capped or throttled. You said you changed escs, did you change the power wire to the esc from the pdb? There could damage to that wire or to the pdb its self. (If you can, try using different pads for the esc on motor 1, see if that makes a difference

2. The motor value to the esc comes from the flight controller, it could be a problem with the signal for a number of reasons, first question is when you describe the problem are you driving the motors from the radio or from the configurator?

[TwoFourty]

I am driving them through cleanflight. #1 arm always spins up really slowly. Three motors are smoothly spinning on arround 1011 and number one has just impulses. Atb around 1030 all motors are spinning but #1 spins even visibly slower. You can stop it by touching the nut, when others have some power in them.


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[orfordness]

OMG. Never thought about it. I use Matek PDB mounted under FC. And when i look back, i had a good crash before this happened. Definetly gonna check it tommorow.
Thanks for that, your kindness.

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If you have access to a multi meter, measure the resistance between the PDB pads, all should be a similar value.

[Cheredanine]

I am driving them through cleanflight. #1 arm always spins up really slowly. Three motors are smoothly spinning on arround 1011 and number one has just impulses. Atb around 1030 all motors are spinning but #1 spins even visibly slower. You can stop it by touching the nut, when others have some power in them.


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Ok mate so when you use cf to drive them you take sensors etc out the loop, the FC is trying to send a set value
The escs andnthus the motors should act the same, particularly once they have been calibrated through cleanflight (not blheli) correctly - that removes any issues with the timing
Electrical jitter/interference could also impact the signal, but since you are doing this with props off nothing is under load so not much should generate any great emi or electrical jitter
Check the load on the flight controller but this is all pointing at the pdb throttling the power