I am having a bit of a dilemma and not sure what's the problem here. I was on my 4th pack of the day while I crashed the quad fairly lightly as it got caught in some tree branches that I did not see and fell in small grass + some mud. After I cleaned it a bit and visual inspection I take off again but there was a weird noise so I land straight away. I realized that one of the propellers is loose so I tighten all the nuts and try my 3rd liftoff on the same pack. As you can see in the video below, the quad just goes sideways for no particular reason. As I was approaching to pick it up, the video feed cuts off and I only can see it in my googles if I am no further than approx 25 cm from the quad. 



Then flew it a bit LOS just to finish that battery and the quad was absolutely fine with a very normal response. I've got a RushFPV Tank VTX on it and once I got home, I made sure that all the connections are fine: took out the MMCX-SMA adapter cable and put it back in, making sure is properly pressed all the way, I have changed the antenna with 2 other ones that I know for sure are fine and also I made sure that I am on the right channel/band. All the connections are fine and the only thing that I don't have at the moment is that mmcx-sma adapter to try with another one (I've got 2 on order and should be delivered tomorrow). Giving the video above and the video cuts off a few seconds after the crash, not sure what is the problem . Everything I've tried did not help and I only get video in the goggles if I am really close to it. Any other ideas? Do I need a new VTX?

Sounds like a silly question, but did you definitely check the channel that the VTX is on properly in case it got knocked to a different channel? That's the sort of picture you can get if your VTX is on one channel and your goggles are on a different (although close) channel.

(24-Jan-2020, 12:23 AM)SnowLeopardFPV Wrote: Sounds like a silly question, but did you check the channel that the VTX is on in case it got knocked to a different channel? That's the sort of picture you can get if your VTX is on one channel and your goggles are on a different (although close) channel.

Yes I did, I am 100% sure that I am on the right channel and band. If I change it in the goggles then I don't get any video but when I am on the right one at least I get something very close.

Sounds like the Rush VTX is in Pitmode. Is the power LED blinking?

(24-Jan-2020, 12:40 AM)Sugs Wrote: Sounds like the Rush VTX is in Pitmode. Is the power LED blinking?

Bingo! You are the man! Yes, it was in pitmode. I had no idea what is about but now I know...I learn something every day. However still don't understand how it got into pitmode. Anyway, problem solved. Thank you very much!!!

Without seeing which way your VTX is orientated it's difficult to say, but if the power button on the side of the VTX hit something and got pressed in when your quad crashed, that could have caused it to switch into PIT mode. Holding the power button in is how you switch it into PIT mode.

Thanks a lot! Yes that make sense then, the power button is on the side and very accesible...maybe I need to reposition the VTX. I've switched off he pitmode via smartaudio but I've just read in the manual that this can be done by holding the power button. Thanks a lot guys, I appreciate your help and I'm happy that I learn something new today.

I had a similar thing happen to me and it was the MMCX connector had been pulled out when the antenna was bent back during a crash. Checking that connection is another good thing to check for something like this. Mine was work g further away than 25cm, but it was pretty bad.

Well, it seems like I have bigger problems. After I took out the VTX from pitmode went out today for more flying. The first 3 packs were absolutely fine, no issues, no crashes. On the 4th pack just lost the video feed in mid-flight (only a few meters from me) so I have disarmed it and force landing as it was not far from the ground. I've noticed that the VTX was again on pitmode. I have disconnected and reconnect the battery a few times and sometimes it goes in pitmode and sometimes not (but mostly will it just go into pitmode). In one of the times when was good, I put it back in the air for a very slow flight but then again it got into pitmode midflight and I had to force land it. Then there is another problem, most of the time I cannot arm it anymore and I get NOGYRO warning on the OSD, but then disconnect and reconnect the battery a few times and is fine again. It seems very intermittent...when it says NOGYRO, if I connect it to BetaFlight the gyro seems to be disabled and the figure is not moving on the screen. I've got a Mamba F405 F40 Mk2 Flight Stack . Is true that I've crashed it so many times and land it in mud and wet grass as I'm a noob and I was actually wonder is still going strong...it seems like I've found its limit. I might desolder all the connection, clean the pads and solder again. Any other ideas?

Unfortunately if you get a status of "NOGYRO" it is usually game over for the flight controller and there is no way to fix it because it's a hardware issue and you have damaged the gyro chip beyond repair, likely due to all the crashes you've had. It's going to be new flight controller time I'm afraid.

Your VTX switching into pit mode may be a consequence of the faulty FC, especially if SmartAudio is being used to control the VTX settings.

I would take it one step at a time and replace the FC, then see if your VTX issues have then resolved themselves. If not then you can continue troubleshooting the VTX problem further.

I was afraid that might be the case. What annoys me the most is that the issue is intermittent...it seems like randomly happening and some time is just fine. I'm looking into ordering a new FC and take it from there. I was warned that this is part of the hobby and to be fair I am impressed how long it lasted...it went through a lot of abuse for the last 3 months as this was my first ever FPV quad...almost every time got soaked (as weather here is miserable) and full of mud. But I have progressed, very slowly but now I am slightly better. Thanks a lot for great advice!

Maybe conformal coating is in your future?

Deal

It was conformal coated from the start. Otherwise, it would have not lasted so long because I soaked it so many times. It's a shame that I got the FPV virus at the start of winter.

Update: I don't seem to get "NOGYRO" anymore, but the VTX keeps randomly switching to pitmode but not always. I will also try to update the BetaFlight firmware tonight but in the meantime, I've got a new FC on order.

Could be some moisture has finally found its way into some of the components. Maybe a good drying out in a bag of rice is in order.

(24-Jan-2020, 04:08 PM)Birbal Wrote: It was conformal coated from the start. Otherwise, it would have not lasted so long because I soaked it so many times. It's a shame that I got the FPV virus at the start of winter.

Update: I don't seem to get "NOGYRO" anymore, but the VTX keeps randomly switching to pitmode but not always. I will also try to update the BetaFlight firmware tonight but in the meantime, I've got a new FC on order.

Use a magnifying glass to look at the solder joints around the gyro chip. It's possible some of the joints have gone bad/cracked and are creating an intermittent connection. It would probably be worth re-flowing the solder on the gyro connections, although with conformal coating on the board, trying to do that probably isn't going to be easy because you will need to remove the conformal coating first. That's the one downside of conformal coating - it can make doing repairs difficult.

I tend not to fly much (or at all) during winter for that very reason, so I'm looking forward to spring/summer because the last real flight I managed to do was back in October. I have limited places to fly around here and my usual spot has turned into a quagmire, so it's currently a no-go zone.