Locked out, no response.

When I was doing a vibe test on one of my 500's a few weeks back, ( no main blades, spooled up on the ground ) I noticed I suddenly had no response. No TH, No IU1, IU2, Normal, didnt go to failsafe settings, nothing. Had to reach down and undo the batt to shut it down. Thought perhaps this was an Rx antenna issue ( RX 802 )Relocated and secured the antenna's.
I have 6 flights on this heli with no issue, until yesterday.
I was in a very low ( about a foot off the ground ) side in hover, about 20 feet in front of me, when I realized I was getting no response to my corrective inputs. Again, no TH, no failsafe, nothing. Just watched as it gently touch down and go nose over until the main blades hit and laid it over on its side. Again, I had to disconnect the battery to shut it down. The motor was still running after it stripped the main gear, so I had to yank the wires to get it shut down. The Rx had full steady light. Looks like it never lost the signal. Range test was very good.. I couldnt get far enough away from it at this particular field to get it to go into failsafe.
The other two 500's and my 700 are grounded until I can figure out what happened. Any ideas are welcome.
Devo 8S, Walkera 802Rx, Deviation 4.0.1.

Sounds like the problems I, and a few others, were having with the 2702rx's a while back. I would replace the rx.

Yeah, I've been trying to decide how and which way to go. I have the 802Rx's on everything, 3-500's and my 700. So far this heli is the only one that locked out, didnt go to failsafe, no TH..so I'm REALLY very nervous now to fly anything. I got spoiled by the 2801Pro. It never even glitched on me in 4 years. This was the very first complete signal loss I've ever had, and just really thankful it was on a 500, at about a foot off the ground.
I'm seriously considering reverting them all back to the 2801Pro.
I dont have any idea how to try to diagnose this to see what happened. RX? TX? Software?...I havent been able to duplicate the issue yet on the bench. It needs to be rebuilt before I can do a full spool up.

The 2801 is a solid tx, but i had lock outs due to the faulty 2702v rx's. I had two 2702v rx's that developed this lock out problem over time. But there are others that have 2702's and have had no issues. Im pretty sure the problem is in the individual rx. It never happens on the bench but about every 20 flights, sometimes less, i would get a lock out. I tried different placement, but it would lock me out less than 20 feet away with the rx in plain sight. I also tried a high amp bec, cc pro 20a bec, and it still happend. I no longer use those rx's and I no longer have lock outs.

Yeah, I have to say, it REALLY shakes up my trust. I have one new 802rx in the box I was saving, maybe I'll try that. So far, two other 500's flying the 802 rx's also, havent had an issue, but I havent been flying very much. Time and weather has been an issue. I'd like to figure out what the issue is. Right now, I'm affraid to put the 700 up not knowing if its a Tx issue? Rx issue, Software issue? Wrecking the 700 would suck, but hurting someone would kill me. Is there a way to confirm or eliminate software as an issue? Then I could move to hardware....

Blayd wrote: suddenly had no response. No TH, No IU1, IU2, Normal, didnt go to failsafe settings, ...
... The Rx had full steady light. Looks like it never lost the signal.

Did you switch the TX off in order to trigger fail-save?
If you switch the TX off, the RX should indicate the signal loss with a flashing LED.

If the LED stayed "steady light" although you had switched off the TX, this would indicate a fault on the RX side. (this way you may exclude a fault on the TX side)

Thanks for the reply. No I never had that much time. Once I noticed no response, I went to TH, switched it twice, no response, went to "normal", ( my normal is "0" throttle to arm the ESC) No response. By that time, it was doing a very slow nose over when the mains hit. The Rx was solid. Since starting to fly with Deviation installed, I do a failsafe check prior to any flight. Failsafe checked out just before the flight. I have to say, it acted like it just locked out on last command. Last command was holding a side in hover at about a foot off the ground. When it was locked out, it started drifting.
Thanks for the reply.