(04-Jan-2019, 11:21 PM)MicroFn Wrote: I'm not sure about this because the board in the video is a Dalrc F405 and mine is a Omnibus F4 but what i did was..

i connected my 2s lipo battery to the FC and then i put the negative probe of the multimeter on ground then the red probe of the multimeter on the last pin on the USB, the pin next to the small square chip its next to the very big one with the sticker on it and my multimeter shows 5.02V.

Then i disconnected the battery i connected my positive probe to the first pin of the USB connector it's the pin above the big chip with the sticker on it then i connected the negative probe to the schottky diode the board has two of them at the bottom and on one of the two pins i get a beep, both schottky diode's give me a beep and a little battery sign also comes on my multimeter every time i checked both schottky diode's.

I'm not entirely sure I understand what you did there but this is what you need to do...

Put your multimeter into continuity (beep) mode and without a LiPo or USB cable connected to the board, locate the VBUS (+5V) pin on the USB socket. This is Pin 1 of the USB socket. Press the tip of one of your mulitmeter probes against Pin 1 (VBUS).






Locate the Schottky diodes on the board and press the tip of the other probe of your multimeter onto each of the anode legs on each of the two Schottky diodes one leg at a time until you hear a have tested all 4 possible of the possible anode legs.






If you hear a beep when touching any of the anode legs then the Schottky diode that the beep occurred on is the one which is acting as the input/output gate as per my crude diagram below.




You then need to perform a diode test against the legs of that Schottky diode as instructed by Drone Mesh at 04:24 in his video (HERE) to see if it has gone open circuit on either of the gates.

I'm a person who doesn't give up on things easily when i'm fixing it or attempting to fix it i had purchase some voltage regulators thanks to snowleopardfpv for pointing it out i remove the old voltage regulator and soldered on a new one but the FC still didn't power up from the USB port but when i put my multimeter on a diode at the very top it powers up and you can hear the sound the computer makes when a USB is plugged in but as soon as i remove the positive probe of the diode the FC goes off.

What are you referring as top of diode? And where is the other probe? And what mode do you have the DMM on?

(12-Jan-2019, 04:33 AM)voodoo614 Wrote: What are you referring as top of diode? And where is the other probe? And what mode do you have the DMM on?

I'm referring to the two prong diode next to the square thing with a 100 stamp on it, i put my probe on the negative part where the lipo battery is connected to the flight controller the mode is DC 20 this is a classic cheap multimeter i had purchase years ago that use 9V battery the battery hasn't been change ever since i purchased it but i didn't connect the lipo battery to the flight controller i connected the universal serial bus cable to the flight controller then i put my multimeter positive  probe on the left side of the two prong diode and the flight controller comes on, it doesn't power on from the the right side.

You are still not being specific. Which lipo pad, the ground or positive. And on the diode, are you saying the anodes? And is it both anodes or just one.

(13-Jan-2019, 06:02 AM)voodoo614 Wrote: You are still not being specific. Which lipo pad, the ground or positive. And on the diode, are you saying the anodes? And is it both anodes or just one.

The ground lipo pad and it's just one of the anode's, the one on the left, that's why i said if i put the multimeter positive probe on the left side of the diode the flight controller comes on and as soon as i remove the positive probe the flight controller turns off and if i move the positive probe to the right side of this diode that has 2pins the flight controller doesn't come on.

Without you telling us what orientation you have the diode, I don't want to assume. Therefore left, right, up or down means nothing. Now that we establish what pin you are probing, I wonder if your DMM is powering the FC or bridging the two pins? I check both my DMMs and on the voltage settings, neither provide any significant voltage. And in voltage mode, there is no continuity. Thing is quite interesting.

And when i open Betaflight i could see the Flight controller COM port number i'm thinking about just soldering one black wire on the ground lipo pad and one red wire on the diode pin and wire then together and see what happens.

Good luck. Let us know how it works.

(19-Jan-2019, 08:20 PM)MicroFn Wrote: And when i open Betaflight i could see the Flight controller COM port number i'm thinking about just soldering one black wire on the ground lipo pad and one red wire on the diode pin and wire then together and see what happens.

It's difficult to know without access to one of those flight controllers to trace the circuitry, or without a circuit schematic, but that diode may be protecting your USB circuitry so if you do end up doing that then I would probably just advise making sure you never plug a USB cable into the flight controller at the same time as a LiPo is plugged in because you could end up frying whatever is connected to the other end of the USB cable (PC, phone, or whatever).

Hopefully it will all work out fine. Good luck.

Snow, good advice.