unseen Wrote:Out of idle curiosity, I just dug a bunch of random brand new ESCs out of my spares box and made the same measurement.

V1 RacerStar 20A BLHeli_S : 11K
DYS XM20A BLHeli : 11K
FVT Littlebee 20A BLHeli : 44K
FVT Spring 40A BLHeli_S: 54K

If I reverse the leads on my Fluke and put the positive probe on the ground wire, the resistance rises with each second I keep the probes on the device.

Maybe if there's a significant difference in the measurement between the three motor outputs and ground it might tell you something - there was no significant difference between terminals on the ESCs I tested.

.....

We're here if you need help!

Simply speechless!! I was looking for these diagrams but did not have the patience after it all to bother too much. I work in a hospital biomedical shop (fixing medical equipment), so electronics is my jam! After checking those, I too was impressed of the proximity of the readings among the ones tested. And I too got the same "rising by the second" readings on the ones that I assume are troublesome. No way I can think of to be sure on what part failed, but it gives me a good idea that something is wrong there. An idea I am thinking of trying, is that one of the fets burned up on one of the ESCs. I still have 4 fets on another board that was having an issue. I briefly considered using my hot air rework station to take off the good fets and put them on the bum board. But that is a project for a different day. Loved the reply man, really made my techie heart happy!

I'm glad you enjoyed it!

Here they are in full:

unseen Wrote:I'm glad you enjoyed it!

Here they are in full:

Ahh!!! Good bedtime reading! Thanks again. Will resurrect this post when the new stuff arrives. Should be a blast! I am curious to see the new motor readings as compared to the old ones!

s3npai Wrote:Ahh!!! Good bedtime reading! Thanks again. Will resurrect this post when the new stuff arrives. Should be a blast! I am curious to see the new motor readings as compared to the old ones!

AAAAND the results are in!! Listing the results below, using a 12v Makita cordless and a fluke meter.


Motor 1(smoked motor, results taken after smoke)
1/2 - 391mV
1/3 - 408mV
2/3 - 409mV

Motor 2
1/2 - 409mV
1/3 - 410mV
2/3 - 411mV

Motor 3
1/2 - 409mV
1/3 - 409mV
2/3 - 411mV

Motor 4
1/2 - 416mV
1/3 - 418mV
2/3 - 417mV

Motor 5 (new)
1/2 - 420mV
1/3 - 420mV
2/3 - 420mV

Motor 6 (new)
1/2 - 418mV
1/3 - 419mV
2/3 - 419mV

Now let me state, I am no electronics genius. Just going from what I see here and past experience. The first thing I notice is that the new motors are throwing down nearly 420mV each time. Motor 4 is very close, which I would assume that this is a new-ish motor. It was purchased used, as well as the other 3. The one that smoked is pretty low on the scale down there, and I am suprised it even produced much. Motors 2 & 3 look to be well used, and perhaps approaching end of life. I have already ordered another motor to make it 4 as close to new as possible. Going by my luck on this build, new motors on proven good ESCs, with a new FC, should be good.

Interesting results!

The lower output voltage could be due to the magnets having lost some of their magnetism. If they've previously been abused and have reached temperatures that are too high for the magnets, that would be the result, along with an increase in the motor's kv.

Even so, this wouldn't cause the motor to kill the ESC, so I'm still scratching my head about why you had smoking motors and burning ESCs in the first place.

(21-Oct-2017, 10:39 AM)unseen Wrote: Interesting results!

The lower output voltage could be due to the magnets having lost some of their magnetism. If they've previously been abused and have reached temperatures that are too high for the magnets, that would be the result, along with an increase in the motor's kv.

Even so, this wouldn't cause the motor to kill the ESC, so I'm still scratching my head about why you had smoking motors and burning ESCs in the first place.

Yea, it's got me wrekt as well. The more data I get, the more confused I become. Figured this would be more cut and dry. But, hopefully after replacing all of it, it should work. Right...? Lol.

Fingers crossed!

Alrighty, odd update. So, thanks to the late youtuber Project Blue Falcon(ifyou have not watched his videos, they are a must), I learned of stick commands for the board. So, did a few of the "gyro cal" inputs, throttle bottom-left, yaw straight down, and watched it on Betaflight. Holy christ, that helps. Now granted, sometimes it will stay good, and sometimes it will not hold the cal, but the difference is night and day. Motor and ESC come in today, FC should be here shortly. Hopefully able to wrap this up soon!!

No silly testing by arming the craft on the bench without props please! If the motors spin in the right direction and the motor numbering matches then calibrate ESCs (if not using DShot), add props and go outside to fly.

unseen Wrote:No silly testing by arming the craft on the bench without props please! If the motors spin in the right direction and the motor numbering matches then calibrate ESCs (if not using DShot), add props and go outside to fly.

LOL, gah. You just had to bring that up.. 

Promise! I think most likely I will keep this board after sending it to Cheng for my Eachine Wizard. But I have a good few spare motors now, lol. We shall see how this goes!

ALRIGHT!! Back in business. So, new board is here, and just got it wired back up. Checking for shorts now with my new patented Smoke Stopper™! Is it alright to hook up the battery to the board before the ESCs are on?

Sure, but why?

Power it from USB until you are ready.

unseen Wrote:Sure, but why?

Power it from USB until you are ready.

Word. Have USB powered it a few times with no smoke. Which is bueno. I was also reading your guide and following it religously. Are there any other trouble spots you recommend continuity testing before moving on to mounting up ESCs?

If you are not confident of the quality of the ESCs, you should certainly check the power inputs and outputs for shorts.

Otherwise, just put it together, carefully, accurately and methodically and inspect your work critically.

If you can avoid the temptation to start fiddling with firmware settings, flashing stuff without a need to or engaging in meaningless pre-flight testing, I reckon you'll be in the air before the weekend is over!

(And probably back at the bench a few hours afterwards. )

Oh, here's the most important rule of all:

Don't connect anything to anything else unless you are completely confident that wire A should be connected to pad B and you understand the purpose and function of the connection. Even if you are sure you're connecting the right things, double check yourself.

I know you work with electronics and I'm sure you already understand this rule and have probably learned the hard way why the rule is so important! For any other beginners reading this thread who don't have any background in connecting badly documented electronics, this post is more for your benefit. If you're not sure, ask! There's no such thing as a bad question, only bad ways of asking them! Questions are also cheap, compared to flight controllers, ESCs, motors, etc.