DX7 & AR6200 Issue

[joe.lel]

IMPORTANT INFO ADDED 2 AND 3 POSTS DOWN


Please bear with me the post may be a bit longwinded, but i want to try and be as precise as possible

The Raptor went in again today, i am 90% sure it was the fault of the on/off switch on the heli.

I have managed to replicate the issue of what happen on the bench, but this has posed more questions than answers.

If i cycle the power very quickly on the heli switch (doesnt always happen), the heli goes into the mode when you first turn it on (waiting for the signal from the TX).

Now this particular period of time results in the pitch servo maintaining a -4 degree pitch (bottom throttle position) until it re binds to the transmitter.

What i do not uinderstand is why it does this, if the receiver lost power in flight very briefly, and then came back to life, whilst waiting for the signal, it goes into this negative pitch situation.

I am assuming that this signal should be for the throttle servo, but on first start up (if i turn the heli on first) the throttle servo doesnt move. If when its bound i turn the TX off it goes into failsafe as expected on the throttle and the pitch is unaffected. But this only seems to be if the link is lost between the TX and RX due to the TX. Not the oter way round.




So to sum up.... RX on first = pitch goes to binding position, throttle does nothing. All ok when bound

TX on first as usual.... all ok.

I'm a bit worried that if the rx loses power etc momentarily in the air, its going to go in again as until its bound the pitch goes to binding position.

If that make sense

[maderdog_1024]

i would be checking the software version of your TX and RX as im almost 99% that there has been an update by spektrum.

remember failsafe is on tx loss only.

worth investing in a quality switch.

[joe.lel]

I am removing the switch from theeqution, thanks for the info on the spektrum, will look into that for sure.

Found this idea on Helifreak, so may also try that.....

I know the servos dont go to a fail safe setting BUT they DO go to the bind position on RX power up!
So I also make my normal throttle curve a flat 0 and put the stick at center and bind.
What this will do for you is on power up the servos will go to the center stick position rather than low or some other screwy positition.

Some might say who cares..... Well having a power loss reset myself once, I can tell you when the RX powers back up in the air you dont want it to go to some wierd swash positon!

.....................

Cheers

Joe

[joe.lel]

Also found this which makes ALOT of sense.

Hope it helps others

Well another thing I found out is when the dx7 and 7000 receiver are linking up the servos will go to the position when they were binded for 1-2 seconds while the link is established. which is low throttle which is also FULL NEGATIVE. Well when the regulator lost power and then the power came back on the servos went to the bind position which is full negative hence the reason that the helicopter went into the ground the way it did. After the crash everything tested fine on the bench. So when binding your reciever I would suggest to hold the bind switch with the left stick centered and as soon as you turn the radio on to bind it flip it into throttle hold. That way you will have all the servos centered and the heli will be in throttle hold when it is establishing a link. Then if for some reason the helicopter loses power and then comes back on the servos will go to the center or zero pitch position instead of full negative.

[joe.lel]

Anybody have any feedback or suggestions on this, as the possible solution didnt come from the holy grail that is Heliaddicts. LOL

[maderdog_1024]

from my understanding of the dx7 and the manual, it only failsafes on the throttle and all other servos are put to neutral or last input.

test on the bench to check

[joe.lel]

from my understanding of the dx7 and the manual, it only failsafes on the throttle and all other servos are put to neutral or last input.

test on the bench to check

Thats correct but this isnt about failsafe, its a reboot after momentary power loss in flight, servos will go to binding position until a signal is established again. resulting in full -ve pitch possibly.

[maderdog_1024]

yep if that is the case i would read here;
Look what Toddsmodels.com is selling now. Spektrum v1.6 6100's. Brownout fix! - RC Groups

older spektrum recievers and previous software versions are slow to re-bind after a brown out.

follow the test outlined in the link above and see what yours is.

[joe.lel]

The one in the raptor come back on straight away.

[moyesboy]

If when you power down the receiver and power it back up again (tx always on), you do not get flashing lights on the receiver, then you do not have he latest quick connect software. this means in the case of a power dip it might ake a lot longer to re-establish connection.

The software upgrade is free from horizon hobby uk and it seems they almost always turn the rx round inside the working week.

Have a good look at all the plugs and sockets, once or twice I'vefound the crimp backing out of the plug leading to an intermittent loss of power (on a pre flight check!).

It is true - there is fail safe, and bind position.
Its easy to end up with bind position as full negative pitch!
Bind in throttle hold and zero collective.
If you trawl the forums then there have been quite a few reports of intermittent power leading to a heli that has just taken off slamming into the ground on full negative pitch.

I had the wire fall of the rx battery wheil hoveing upside down with my knight3D, and the result was a remarkably gentle crash. Throttle went to idle, and lots of negative pitch! It was an intermittent loss of power (broken solder held in place with heat shring on a deans) so it probably did the bind position thing!

In a fail safe it will go to the bind throttle positon but hold the last known tx position with all the other channels. This is independant of the pitch and throttle curves.
ie closed throttle doesn't mean negative pitch.

Having messed about switiching tx and rx on there seems to be another state which is everything free wheeling unpowered until the rx picks up the tx.

[joe.lel]

Thanks for that, i d get the blinking light etc and the receiver is also brand new.

It did it with 2 seperate receivers etc, so the only common link is the battery switch, which is now in the bin. Iam 99% sure that thisis what caused the power failure on the rx and somehow made it go into the bind position on re-connection, as buy the time the heli hits the floor its all working ok again.

This was very hard to replicate on the bench as 99% of the time it would go into failsafe mode and connect virtually instantly on reconnection of the power switch.

I have now bound the heli with a tiny amount of +ve pitch as atm i dont do inverted, and hold on the throttle, so should the problem arise again the heli should hover for a couple of seconds (hopefully), giving the receiver enough time to re-connect. But hopefully that is a long gone issue as i have removed the switch!!