Q: troubleshooting 9x m128 green - in flight 'power-on THR check' + low voltage
Posted: Sun Sep 05, 2021 10:59 am
Hi all
I had an in-flight issue today, during my third flight, the airplane became unresponsive to my stick inputs, so I raised the Tx over my head, no luck, then shortly afterwards I heard a familiar beep, so I next I looked at the display, it was showing "warning throttle not idle" like at power-on startup and... the plane crashed out of sight...
Then I pressed the keys and looked at the display. I noticed the Tx voltage was low 3.4v or so. However Tx sort of operated again though, I was able to use the Rssi info to 'home in' when walking towards the crash location.
I thought one of the cells of the Tx battery had died (it happend to me on a Rx pack) but when I checked them at home both cells were at 4.1 volts !
After turning off the Tx, and turning it back ON, the voltage displayed is normal.
By searching on the openrcforums quickly , I have seen threads about watchdog malfunctions, restarts (but I did not quite understand everything) and that the voltage displayed was going to be half of the true value.
I have also read about removing some caps to the switches/keys input pins, replacing a voltage regulator, troubleshooting the backlight ribbon cable... faulty bandgap devices (mine enabled and is showing 249 at the moment)...
So I am confused.
1) Is there a way to troubleshoot my unit, in order to be sure about the cause ?
Right now i have the Tx sitting at home , turned on , expecting it might replicate what happened this morning. It has been trouble-free for an hour, but I am not doing anything to the switches/keys. Would the test require pushing the keys and dual-rates switches many times until the bug happens ?
2) Also, I had kept the Tx ON continuously for about 40 minutes - is it a bad idea, would it be better to turn it off then on, between flights ?
3) Or was I asking for trouble by running firmware er9x-128.hex anyway instead of er9x-128Green.hex , and should I replace it before the next flights ?
4) Can anyone comment whether the m128green becomes totally free of the watchdog issues after flashing it with er9x-128Green.hex ?
I am asking this because with today's crash this time the plane can still be fixed (several hours of balsa work) but if similar stuff could still happen again (even if it is less often), I do not want to run the risk, because I might not be so lucky another time ... so I would consider using my m64 instead - ( or upgrading to a Radiomaster TX16S sooner than planned ... ).
Thanks
I had an in-flight issue today, during my third flight, the airplane became unresponsive to my stick inputs, so I raised the Tx over my head, no luck, then shortly afterwards I heard a familiar beep, so I next I looked at the display, it was showing "warning throttle not idle" like at power-on startup and... the plane crashed out of sight...
Then I pressed the keys and looked at the display. I noticed the Tx voltage was low 3.4v or so. However Tx sort of operated again though, I was able to use the Rssi info to 'home in' when walking towards the crash location.
I thought one of the cells of the Tx battery had died (it happend to me on a Rx pack) but when I checked them at home both cells were at 4.1 volts !
After turning off the Tx, and turning it back ON, the voltage displayed is normal.
By searching on the openrcforums quickly , I have seen threads about watchdog malfunctions, restarts (but I did not quite understand everything) and that the voltage displayed was going to be half of the true value.
I have also read about removing some caps to the switches/keys input pins, replacing a voltage regulator, troubleshooting the backlight ribbon cable... faulty bandgap devices (mine enabled and is showing 249 at the moment)...
So I am confused.
1) Is there a way to troubleshoot my unit, in order to be sure about the cause ?
Right now i have the Tx sitting at home , turned on , expecting it might replicate what happened this morning. It has been trouble-free for an hour, but I am not doing anything to the switches/keys. Would the test require pushing the keys and dual-rates switches many times until the bug happens ?
2) Also, I had kept the Tx ON continuously for about 40 minutes - is it a bad idea, would it be better to turn it off then on, between flights ?
3) Or was I asking for trouble by running firmware er9x-128.hex anyway instead of er9x-128Green.hex , and should I replace it before the next flights ?
4) Can anyone comment whether the m128green becomes totally free of the watchdog issues after flashing it with er9x-128Green.hex ?
I am asking this because with today's crash this time the plane can still be fixed (several hours of balsa work) but if similar stuff could still happen again (even if it is less often), I do not want to run the risk, because I might not be so lucky another time ... so I would consider using my m64 instead - ( or upgrading to a Radiomaster TX16S sooner than planned ... ).
Thanks