iFlight Succex f4 only the first 3 beeps

Blindprogression · Sep 1, 2020

I bought the iFlight Succex Micro F4 V2.1 16x16 stack. When I only plug in a battery, I get the first 3 tones from the motors. If I plug in the USB cable and then plug in a battery I get all 5 tones. This is the second stack to do the same thing. I get no video and no power to the receiver. I measured the voltage on the flight controller's 5v pad for the receiver and only get 0.8v. The 5v pad on the flight controller that's for the buzzer and LEDs reads 0.82v. All I've done is take the stack out of the box, solder the power wired and capacitor on and solder the 3 wires for the receiver on. All solder connections are good and nothing is bridged or crossed. I am new at this as it's my first build, so am I missing something? When you buy a stack do you have to upgrade firmware?

I can spin the motors in Betaflight. I'd greatly appreciate any advice. Either I've gotten 2 bad stacks in a row or I'm doing something wrong. The ESC has a solid green light when I plug in a battery only and the flight controller has a solid red light. When I plug in just the USB I get no lights on the ESC, a solid red light and flashing blue light on the flight controller. If I plug in the USB and a battery I get a solid green light on the ESC, a solid red light and flashing blue light on the flight controller.

HighTechPauper · Sep 2, 2020

Double check the pinout for the cable that goes between the ESC and the FC, they are often not pinned correctly from the factory, check that the connections are going to the correct pin, make sure it all makes sense. After that it seems the the ESC isn't providing 5v or battery voltage, whichever this stack is meant to do, to provide the 5v to the FC.

okw · Sep 3, 2020

I looked up this stack and there appears to be header pins that directly connect the ESC and FC together, so that should be connected properly. I'd measure the VBAT pin voltage in the header that connects the boards together. Be careful not to short the VBAT pin to the GND pin next to it with your probe. Maybe have a smoke stopper hooked up in case you do short the pins.

NeoCloneOne · Sep 5, 2020

It seems that your ESC is working fine (the 3 tones on battery hook up). But looks like your FC is not getting the proper 5V input supply (except from the USB plugin). Remove (disconnect) your FC from the stack and carefully check the voltage between the 5v supply pin of the interface connector and ground. If you are getting it properly, then sorry to say, the FC is bad. It is possible to have 2 bad FC's in a row. It has happened to me. I've had a similar experience with a different Succex stack and that's why I don't buy that brand anymore.

Blindprogression · Jun 4, 2021

This is late getting back, but the problem was the header pins. No matter how much I tightened the stack screws, the FC was not getting enough power. My 5v pads were getting 0.81v on 3 of the exact same stacks. I got the last one to work by taking the rubber spacers out, but then the FC touched the ESC and blew up. I got these stacks from a bad batch or something. Very frustrating when you're new at this. I kept thinking I was doing something wrong. I went with a Mamba 20x20 stack and that worked fine. That created a new problem though. My 3" Tadpole frame doesn't accept 20x20 stacks. So I cut my own bottom plate from some carbon scrap and drilled 20x20 mounting holes. I flew the quad like that for a month or two until I bought an AIO board and the adapter plate.