Pixhawk goes straight to flashing amber main led

Hey all, I am new to pixhawk and after about a month I have given up trying to put my head through the wall. I have two pixhawk units and each do the same thing so clearly I am setting this thing up incorrectly. If I load arduplane via mission planner and go through the setup wizard I get to the point where I presumably could arm and fly. Unfortunately all the plastic brick of hate and anger does is blink yellow a few times, go to the red and blue for about a second and then back to flashing yellow. The safety switch gives 3 rapid flashes and then a pause. I have slogged the internet for days but all I can come up with is the board is in some sort of fail mode and won’t arm. If I hold the arm switch for 5 seconds till its solid red it lets me work the elevens but not the motor [ I’ve got the pixhawk in a simple flying wing ]. Every video I watch shows the blinking blue “looking for gps lock” state but mine never does that. I am using arduplane 3.7.1, a taranis plus, and an X8R connected via sbus. PLEASE someone with some troubleshooting experience shoot me some help. I can usually work this sort of thing out myself but this unit is too complex and I have no Arduino experience so I’m outa ideas on things to try.
thanks in advance for any help - Dave

If I hold the arm switch for 5 seconds till its solid red it lets me work the elevens but not the motor

Yes, That’s because your plane is most likely refusing to arm.

The plastic brick of hate and anger is trying to tell you something - Blinking yellow indicates a failed pre-arm check or a radio fail-safe (source). It looks like you’re failing a pre-arm check

What message do you see in mission planner when you try to arm the vehicle? You should see the messages tab in the flight data page to know which checks you’re failing. You can use that get some more information to try and diagnose your problem

If you want to, you can also disable the arming checks parameter (not recommended, though).

On the flight data page under the window with the HUD on it there should be a tab “messages” check and see what it says when you try to arm. I agree with Nihal, it is failing a pre arm check somewhere, read up on what it actually checks during a pre arm and then work through each one yourself one at a time and see if you can’t find the problem. Check your calibrations, if your throttle PWM isn’t low enough when then the throttle stick is at its lowest then it registers it as a throttle input and won’t arm, check your GPS connections, are they plugged into the right ports? Seems stupid but I have done that one before when I was starting out, on the pixhawk boards it is easy to to do if you arnt careful. If your compasses arnt calibrated, orientated or selected properly during the set up you will get an amber light. Also if the board accelerometers are not calibrated properly you might have issues trying to Arm.

The three places to focus on are:

first of all your connections, ensure everything is plugged in where it’s supposed to be snugly and in the right polarity.

Secondly run through your mandatory set up again, set your radio up first, take out all trim and expo for your radio calibration, then run the calibration. check your compass that you have selected the proper orientation and settings for your compass prior to calibrating, and ensure you get a good calibration, it is worth unchecking the self complete box in the live calibration window and only clicking done when you have full coverage with all the data points gone and no errors showing.

Go through the accel calibration again, hold the plane as steady as possible when you do this.

And thirdly have a look at the checks your board does when the arm command is given, I think in one of the tabs in mission planner on the flight data page there is even a checklist with a system of red and green lights indicating a pass or fail for each one. Then when you have more of an idea of where the problem(s) are read up on the wiki and go from there.

Trouble shooting is a long and winding road but it’s what makes up a large part of using one of these boards, and is a large part of the hobby behind one of these. As soon as you figure one thing out there is something else to learn waiting for you right behind it. Time spent reading the wiki and the forums is always time extremely well invested, even if it’s not relevant at that point in time there is a high chance that at some point it will be. These controllers their capabilities and the support behind them are amazing, I shudder to think what you would pay for an off the shelf plug and play system with half of the functionality as one of these.

Thanks so much for the reply! Sorry it took so long for me to notice [my email notifications weren’t updating on my phone for some reason]. I saw a few posts mentioning the preflight red and green messages so that was the first area that I played with. I can get the first 4 that are color coded to go green. I also tried turning all of them down or off but still no luck. After some more playing around I have determined that the only area where I have any indication of a problem is one of the last parts of the setup wizard that has a failsafe check item that’s not on the main page, it asks me to arm the craft from the radio. I can’t figure this one out because none of the youtube videos I watched about setting up the radio for a pixhawk mention anything special. The ardupilot wiki says to hold the stick to the bottom right to arm but that doesn’t do anything. That failsafe or preflight check item is the only one I can’t get to turn green. I don’t know if that is the root of my problem or just a symptom of my board failing preflight for some other reason. I have seen something about setting up something differently on the tyranis regarding a minimum ppm signal value to satisfy the pixhawk’s zero throttle to arm condition but I’m still kinda vague on how to actually accomplish that. thanks again - Dave

as far as the ppm thing goes, calibrate your radio (TX) in MP, then look at the ch3 min rc value. on my setup (same as yours) the value is I think 983. go to the failsafe setup screen and make sure the throttle failsafe value is below the value of ch3 min. also make sure your failsafe settings on your TX is set to NO PULSES. so that failsafe engages properly., but unless the fs value is currently higher than your it’s not your proper here. my advice is ditch the wizard and go through each configuration step yourself

Ok so I got somewhere new today while playing with transmitter settings. I turned throttle failsafe back on. I think in the guide it refers to this as rudder arming? I checked my min pwm setting and as you stated Josh, my min calibrated value was around 980 and the default failsafe setting is set at 950, so that looks fine. While messing with the radio config. I realized I was having an issue with mission planner not reflecting changes in my flight mode switch selections outside of the flight mode screen itself but I tried changing modes in the failsafe setup tab and after setting it to manual flight mode there it finally switched from RTL on the main flight data screen and the big red failsafe FINALLY went away on the little attitude indicator, kinda weird but I ran with it and tried to rudder arm with the transmitter and now as you warned ktrpilot, I’m on to the next problem. It wouldn’t give me an error specific message while in the failsafe mode and that was caused by my funny issue with the flight mode not being received properly I guess, now I get a big red “PREARM - compass offsets too high”. I tried recalibrating several times. I noticed that the little red plane on the google earth overlay is clocked about 90deg. left of the pixhawks actual orientation but it reacts fine to being turned one way or the other. I’m not sure if there is a manual offset or a magic trick to get the compass happy but at least my problem now has a name. Thanks for the input guys I really appreciate it.