Alright guys, a bit disappointed here.
I’ve lrdered a second q90c because it was cheaper than getting all the parts, and it is a good beginner quad for me. I’m still going to get a mantis I think next week, and after that get myself the taranis...

That said, I thought it was the motors, but now I’m thinking my fc is the problem.

I had crashed, motors weren’t responding.ordered new motors. So tonight, fresh good quality solder, good flux, steady hand and my temp controlled iron. Got my wires Lee tinned, board was pre tinned, the solder job looks good. Not a cold solder, nice and shiny but not too much solder. No solder spills on the board, no bridged gaps.

Quad turns on, camera works, calibrate lights flash, arm motor lights flash, (at this point I’m excited, I haven’t been able to fly for several days now) and then nothing. No smoke, no bad smells, not a sound from the motors.
I’m guessing it’s the fc on the quad. So I guess worst case I have a full set of spares minus a fc for the frog, not the worst case senario here.
Trying to remain positive, will be flying by next wed. Again, have a dumpy WiFi quad for now, and my girlfriend is much more receptive to me buying some more quad gear.

So I’m gotten the frog again, for 60 bucks it seemed worth it, if only because I already have mostly every part is extra motors as repairs. I’ll be getting another quad of some sort next week I think, and then I’ll build a 5” from scratch.

I’m going to my friends tomorrow and I’ll plug the frog into beta flight and see what she says. I know that it’s stated several times in the manual to change nothing but basic pids, so I won’t. In bf, what should I look for to determine my problem here?


Thanks for reading guys, someone get a cool flight in for me! In the meantime, I’ve been studying hard on everything I should know...

If there is no sound at all from the motors, it's most likely to be your ESC's?
If it's a problem with the FC, you should at least hear beeps from the motors when powering up, but probably not the confirmation beeps (the last beeps), because there is no ESC signal.
Keep us updated

(19-Apr-2018, 04:29 PM)Oscar Wrote: If there is no sound at all from the motors, it's most likely to be your ESC's?
If it's a problem with the FC, you should at least hear beeps from the motors when powering up, but probably not the confirmation beeps (the last beeps), because there is no ESC signal.
Keep us updated

So my fc for the q90c is an all in one type board, and there was never any beeping, just the led blinks to confirm calibration and thatbthe quad was unlocked.
About to head to my friends and see what betaflight brings up

A quick edit, maybe I missed this when I first got the frog, but the vtx seems a bit warm (can feel slight warmth over it on the case) when powered on. Video otherwise works fine, not sure if I missed that and it’s normal or not.

It says the extension to download betaflight is not found. Unable to download betaflight ... idk it’s probably this Apple computer. Now it’s saying the website isn’t secure.. trying to run free rider says it’s not compatible with my computer

oh, sorry i missed the part where you said Q90C... it's a brushed quad isn't it? Brushed motors don't make sound like brushless motors do, so that's completely normal.
Do the motors speed up in the motor tab in Betaflight?
If that doesn't work then there is something wrong with either the FC (probably the FET's), or all the of the motors (which is less likely).

(19-Apr-2018, 11:18 PM)Oscar Wrote: oh, sorry i missed the part where you said Q90C... it's a brushed quad isn't it? Brushed motors don't make sound like brushless motors do, so that's completely normal.
Do the motors speed up in the motor tab in Betaflight?
If that doesn't work then there is something wrong with either the FC (probably the FET's), or all the of the motors (which is less likely).

I chnged all the motors. Betaflight won’t open on my computer idk why

So I downloaded and opened it on another computer. Couldn’t open my quad on the program. On top of that, the vtx got pretty warm again plugged into computer, however it still transmits video. Not sure if related but giving up on this as I don’t know what to do..


Update_
Not sure how but i got it doing something. I re soldered everything, some of the connections looked bad, so I tore the whole thing apart. It spun up for a second, but then stopped, motors got super hot, no smoke, but a smell. Taking it apart again and going to make sure all solder points look good, and see if that fixes anything. Again no clue why it decided to spin back up. Wouldn’t take off, it flipped twice, and then started bugging out, that’s when I cut power, noticed the motors were hot and smelled suspicious. Didn’t smell Burnt, no smoke, but there was something... hopefully I can figure this out..

Hello Jake,

I read that you have already replaced all four of the motors.
Since I was unfamiliar with your particular drone model, I googled "Q90C" and from what I can tell, your brushed motor quad has an "all in one" flight control and ESC (electronic speed control" board.
I was hoping that you might be able to swap out just the ESC, however upon closer inspection, this will not be possible.

So while I am relatively certain that the ESC is the fault with your quad, you will most likely have to replace the FC/ESC combo PCB to get your quad back up and flying.
I hope this lends some help to you.


Good luck,
FPV4ME

(20-Apr-2018, 06:29 AM)FPV4ME Wrote: Hello Jake,

I read that you have already replaced all four of the motors.
Since I was unfamiliar with your particular drone model, I googled "Q90C" and from what I can tell, your brushed motor quad has an "all in one" flight control and ESC (electronic speed control" board.
I was hoping that you might be able to swap out just the ESC, however upon closer inspection, this will not be possible.

So while I am relatively certain that the ESC is the fault with your quad, you will most likely have to replace the FC/ESC combo PCB to get your quad back up and flying.
I hope this lends some help to you.


Good luck,
FPV4ME

I have already purchased a replacement quad, figured all the parts was better than waiting till restock, could be several months.

Will be buying a quad soon that doesn’t use model specific parts because in quickly learning this is a huge issue. That said, 55 bucks I think for a whole new quad, not a huge deal I guess.

My first thought if it flips over is to check motor polarity on the FC. Can you take a pic of the FC for us. Didnt see one on the item description lol. I also notice this runs a 2S lipo, not all 8520 motors can handle this and may cause some hot motors

(20-Apr-2018, 11:21 AM)Drone0fPrey Wrote: My first thought if it flips over is to check motor polarity on the FC. Can you take a pic of the FC for us. Didnt see one on the item description lol. I also notice this runs a 2S lipo, not all 8520 motors can handle this and may cause some hot motors

Unable to get pictures loaded for some reason, says file too big. Anyways motor polarity is correct, double checked that before soldering and took pictures because I took off the old motors. Thinking it’s the esc built in to the fc.

Reduce the size of picture file if you want to upload as an attachment or use the imagur link to upload into the post body.

(21-Apr-2018, 02:59 AM)Jakefpv Wrote: Unable to get pictures loaded for some reason, says file too big. Anyways motor polarity is correct, double checked that before soldering and took pictures because I took off the old motors. Thinking it’s the esc built in to the fc.

Brushed builds dont use a normal ESC, instead they use MOSFETs to control motor speed. And they can and will go bad. I have replaced a couple on my buddys F3 Eachine brushed BNFs before. As well as just upgrading the ones in an H8 mini to run 8520 motors.
Here is a video reference for swaping FETs

(21-Apr-2018, 11:30 AM)Drone0fPrey Wrote: Brushed builds dont use a normal ESC, instead they use MOSFETs to control motor speed. And they can and will go bad. I have replaced a couple on my buddys F3 Eachine brushed BNFs before. As well as just upgrading the ones in an H8 mini to run 8520 motors.
Here is a video reference for swaping FETs

I’ve worked with ecig mofsets, wonder how similar that will be. Will watch this tonight, worst case I have a fc I can’t use so I smell a project coming on!
Thanks for the link! Very interesting stuff.
Also unrelated, but have some violin rosin I was gunna use 90%iso to turn into a soldering flux to see how well that works (I have flux, but I have loads of rosin as well)
I like projects

New quad came in yesterday. First time flying with more than one battery lol. Had 5, 3 of them turnigy, and woah what a difference. It’s a whole new beast with those on it. Punch out is insane compared to stock, and 5 min flight time doing barrel rolls and zipping around the whole time. So fun!

Hooray! Always great to hear when someone gets back in the air!

Re. replacement motors - Like DOP said, most 8520 brushed motors are designed to run on 1S only, if you didn't get replacement motors specifically for 2S they will overheat and may well smell funny. Anyway, glad to hear that your having fun!