Strange intermittent problems with Devo 7E

Hello,

I've been using my Devo 7E with a NRF24l01+PA module to control my 3 V2xx quads.There are no other modules installed.
Most of the time the TX works great but every once in a while various things following will happen -
1.When turning on the TX splash screen and chime will repeat over and over. Turning off and on 2 or more times will make it boot normally. Today it took around 8 switch cycles to get a normal boot.
2.Screen goes blank while flying but everything else works fine. Reboot brings screen back.
3.Screen sometimes displays garbage like ??? and stuff.

These thing happen at random and not together. Doesn't seem to be a loose connection, not connected with vibration or battery level.

TX is totally usable otherwise, just wondering if this could be a common issue with a NRF24l01+PA module addition.

Thanks for any tips!

The garbage display is normal. I've had bad modules\soldering cause the reboot issue.

There are some components which are using the SPI bus altogether (don't know if there are more than one SPI buses so correct me if I am wrong): all modules, the LCD screen and the USB memory are connected to this bus, only the select lines are different for each part.
If you have some bad soldering point somewhere this can affect the functionality of all other devices too. "???" on the screen often means that the font files are not found in the memory, blank screen can happen if the LCD can not be controlled completely, even the need to boot more than once to get the tx running proper can be affected to noise on the SPI bus.

I would recommend to carefully resolder the module / wires (heat up until melting and put some additional solder on it, but take care not to produce any shortcut).

Thanks for the replies. I'll try the throttle thing the next time it loops on boot up.
There could be a connection issue. The nrf24L01 usually induces a gentle hum from the speaker depending on the power level chosen. I'm assuming this means the module is powered up and transmitting. Sometimes the hum is absent and the quad won't bind. Turn off and on, hum returns and quad will bind.
I ohmed all connections when I installed the module, all was ok. The module I'm using is the one with the screw on jointed antenna. Perhaps I will swap it for a module harvested from my V222 TX and see what happens.

A hum over the speakers would be one of the indicators of a "ground loop." I would check you solder connection again. I have the same mod in my Devo10 and no such humming through the speaker, you shouldn't have that either.

I also have humming on all modules. (cyrf, cc2500, A1005) I assumed it was normal maybe somthings diffrent in the devo 7e that makes the speaker more prone to interferance. Either way my 7e works great so its not a big deal

I have this humming since i installed Deviation. I got the 7e as set with
a Super CP and did not mention that behavior with the orignal software.

After starting with 4.01 my TX works fine, but make this noise.
I can stop that for a while by using some of the trimm tabs, 2 or 4 clicks from zero.
The noise is stopping then and i am able to go back to zero or at least to one
step.
After calling the menue it starts again. I am not sure, but i think the feedback beep is initiating this.

...English not my nativ language and it is very late now, so have mercy for this step in.

Well today the TX would loop regardless of how many times power cycled. Advancing the throttle stops the loop but it starts again when it's reduced.
Pulled shell apart to check connections. I decided to move the ground on the TX side to the RF shield. Strangely, when the module ground was removed the TX stopped looping and appeared to boot normally but would not(obviously)bind. Soldered grnd to shield and TX will now boot but it takes a few cycles. Re-soldered remaining connections one at a time, testing each connection, find the miso might have marginal as when it was re-soldered TX seems to boot and bind on the first try but I'll boot the TX many times over the next few days before I call it fixed. There is still the hum or buzz through the speaker. It's loudest at full power and almost silent at low power levels. It also stops during the bind countdown.

Thanks for all the suggestions!

I was having drop out issues with my v2x2's so I decided to replace my NRF24L01 module to see if that made a difference. I also upgraded to 4.0.1. at the same time. When I got finished I found that I could no longer bind to any of my v2x2's. Sometimes I would get the neverending reboot and when I could get it to boot sometimes it would see the module and still not bind. other times it would not see the module. I have 4 NRF24L01 modules and I tried them all. I resoldered new connections to the board and retested the connections for continuity. I also have a A7105 module installed using the TMS spot so my NRF24L01 is using tck. I did notice when I went to replace the new module there was a loose piece of wire that I must have dropped on the board shorting between TMS and TCK. is it possible that could have killed something on my board preventing it form seeing the NRF24L01. Now no matter what I do with any of the builds I cannot get my 7e to see any of the NRF24L01 modules I install. And yes I did enable it in the tx.ini and when I used the nightly i made sure to enable it in the hardware.ini. If I did kill it would installing the 8s upgrade module help repair it and get it working again? I'm not sure where the Tx reads all of the extra modules from or how it sees them or where the bus is located. Thanks!