Hi everybody.
Yesterday I've started to build my first quad-copter. after soldering everything I've plugged up the battery behind a smoke-stopper and everything was fine except that the quad just make 3 bee-bup instead of the normal 5. At first i didn't even noticed it thinking that every PCB has his own sound. 
When i connected the quad to BF i wasn't able to spin the motors and here commence the drama.
I've searched everywhere on the quad and on the internet, checked the circuit but nothing, i see no damage or burning  nor on the FC nor on the ESC.
Well, considering that this one is my first build I've haven't the finest soldering but i can consider myself pretty satisfied, probably some expert eye consider it a shitty work.
After hours scratching my head I've remembered that when i first plug-in the battery I've forgotten to switch the 8-pin connector from the FC and the ESC. I've connected the TLM (esc) with the GND (fc) and the GND (esc) with the R4 (fc).
May I have fried something doing that? The smoke-stopper never opened the circuit.
Actually the FC works when connected to the USB, i was even able to update the firmware. And the esc power up when i connect the battery doing the 3 bee-bup. I've tried all the possible protocols on BF but still nothing.
I don't know what I'm doing wrong and for sure there is something, I'm getting crazy about that.


FC: CLRACINGF7 MPU V2.2
ESC:Tekko32 F4 Metal 4in1 ESC (65A)


P.S. I'm sorry, English isn't my main language, so I'm doing my best to write something that it's understandable by the most, I'll hope I've reached my purpose.
Thanks

I'm sorry to say that those exact symptoms where you get all 5 beeps if you connect a USB cable and then a battery, but only 3 beeps with no USB cable connected means that you have fried the 5V regulator on the FC. Probably as a result of having the ESC-to-FC wiring harness wired up incorrectly.

Never just rely on a smoke stopper. Always use a multimeter to do some continuity checks on the power rails of the FC with before you apply LiPo voltage after doing some soldering work on the electronics.

The options you now have are:-

1. Locate and replace the fried 5V regulator chip on the FC. This will required a hot air rework station and some good soldering skills.
   
2. Use an external 5V regulator to provide (inject) 5V into the FC.
   
3. Replace the whole FC with a new one.
   

(16-Nov-2021, 04:19 PM)SnowLeopardFPV Wrote: I'm sorry to say that those exact symptoms where you get all 5 beeps if you connect a USB cable and then a battery, but only 3 beeps with no USB cable connected means that you have fried the 5V regulator on the FC. Probably as a result of having the ESC-to-FC wiring harness wired up incorrectly.

Never just rely on a smoke stopper. Always use a multimeter to do some continuity checks on the power rails of the FC with before you apply LiPo voltage after doing some soldering work on the electronics.

The options you now have are:-

1. Locate and replace the fried 5V regulator chip on the FC. This will required a hot air rework station and some good soldering skills.
   
2. Use an external 5V regulator to provide (inject) 5V into the FC.
   
3. Replace the whole FC with a new one.
   

I was actually worried about this. What a noob mistake. I think i will buy a new FC considering that i'm good just to solder a cable on a PCB, for sure not enough for a rapair of that caliber. How can i see where the regulator is located? And how can i test the continuity between two board? Is this possible even with the motor?
Tnx

(16-Nov-2021, 05:01 PM)Hattori Wrote: How can i see where the regulator is located? And how can i test the continuity between two board? Is this possible even with the motor?

The voltage regulator will be one of the 3-pin or 5-pin chips on the FC. Sometimes it can take a bit of tracking down with a multimeter and some circuit tracing.

For continuity testing, make sure that there is no short circuits between the LiPo voltage and GND connection or between the 5V pads and GND connections. Additional continuity checks to do are to ensure that you don't have LiPo voltage pad from the ESC connected to one of the motor signal connection on the FC, or the telemetry data connection on the FC, or to the current sensor connection on the FC.

(16-Nov-2021, 08:43 PM)SnowLeopardFPV Wrote: The voltage regulator will be one of the 3-pin or 5-pin chips on the FC. Sometimes it can take a bit of tracking down with a multimeter and some circuit tracing.

For continuity testing, make sure that there is no short circuits between the LiPo voltage and GND connection or between the 5V pads and GND connections. Additional continuity checks to do are to ensure that you don't have LiPo voltage pad from the ESC connected to one of the motor signal connection on the FC, or the telemetry data connection on the FC, or to the current sensor connection on the FC.

Tnx, but I don't understand where should I probe the connection. If I'll probe it wrong whit the multimeter I may fry it right?

Guys, after checking it again I've discovered... to be an imbecil. I've mounted the cable reversed again, the fc is working now and motor are spinning, all seems ok. Tnx for the help, much appreciated.

(17-Nov-2021, 08:48 AM)Hattori Wrote: If I'll probe it wrong whit the multimeter I may fry it right?

When probing anything for continuity you do so with no power connected. You can't fry anything by probing when there is no power running through the boards.

Anyway, good to hear that you found the cause of your issue. It seems that you dodged a bullet this time round