the-plumber

Not trying to be dense here, but . . .

I can't figure out if your aileron setup uses one servo per aileron or multiple servos per aileron. I did see where you have multiple servos on the elevator and I think on the rudder.

_if_ the ailerons have multiple servos per surface, didja unplug each servo one at a time, or simply unplug the servo connector at the Rx ?

Might be one servo in a particular pair causing the problem.

But I bet you already did that and I just missed it.

jkeze

My Feedback: (36)

Mike:
I didnt read all of the replies but also check the igniton system for an intermittent ground. I have seen this happen a few times and every time the radio stops working and the plane goes into the ground

sillyness

My Feedback: (25)

I had a problem like this a while ago. Mine turned out to be my Transmitter, but is sounds like you already tried that. Anyway, the way I troubleshot may apply to you.

I took a table outside and took all my radio gear out in a box. I set up a battery, RX, switch, and started adding one servo at a time, all sitting on the table. I tried different servo extensions, etc. Of course, I had the problem right-off since my TX was bad (took a while to sink in), but the methodolgy may help you.

teletiger

I checke dthe ignition and it was fine ( i ctual sent it to Brisson) and the Rx was replaced, and as for the ailerons there is i per a nd the sme for the stabbs and rudder for a total of 5.

teletiger

Just wanted to give an update. It did go into fail safe on the second flight also. I forgot to set it and the default is last know position.

I took the hardware from the crash and bench tested it trying to duplicate the problem. I did not charge the battreies or Tx. The first thig I noticed was that the Rudder servo gear was broken. I worked those servos for 30 minutes and never had it go into fail safe. Also since I have dual bateries and switches (in parallel to Rx), I would randomly turn one of the switches off for a minute. I had a friend put resistence on the servos, shake the Rx and servos, and twist the leads and extensions. It never went into fail safe.

On both planes I inspected for loose metal contact and found none. There is was good seperation between iginition, battery, Rx, and antenna.

I've called Futaba, Brisson, HiTech, and Tony Stillman. I'm still lost.

the-plumber

Wow.

If I've kept up, everything in the original model went into the new model except for the new Tx/Rx, and the problem moved to the new model as well, yes ?

Ergo, the problem is in the stuff that got moved. Seems like it, anyway.

Are there any servo extensions which might have developed a problem, such as a short between the signal lead and the negative lead ? You'd notice a red to black short because of the melted wiring (BTDT), but you can short a signal lead and never notice any high current symptoms.

I'd have a close look at the Ernst connectors, followed by an inch-by-inch eyeballing of the servo extensions.

Grasping at straws here, but seriously curious about the cause . . .

Stick Jammer

teletiger,
Go back and re-read post #13. There are some items there that I don't recall you've addressed.

teletiger

On post 13...

I did not do a range check at mid and high rpm but now the plane is in pieces. The plane did go into fail safe both times I belive now. I forgot to set the throtlle to idle. I also have been working the batteries for over an hour now and still have not gone into hold or fail safe. The voltage is now down to 6.1 volts and thats under load. Before I thought my tester was not applying a load but i was wrong.

I have sent the ingnition to brisson for a check and might ask them to give it a bosch cap.

teletiger

Forgot, I've inspected the servo extensios and so far have not found a problem but I'm still looking.

Stick Jammer

I know hind sight is 20/20, but that's two things you over looked that could have been the cause. The Rx could have very well gone into failsafe at higher RPM's and then the throttle would have held it's last position.

6.1 with a load should keep everything working. If you took a reading of 6.2 with a load immediately after the crash, your batteries were good.

teletiger

Yes 6.2 volts was right after the crash. This is begining to sound like RF interference from the ignition but I didn't think that would be intermitent like that. The first flight was perfect and the second didn't last 60 seconds.

Also, HiTech just sebt my an email stating that there was a known power issue with the Futaba Rx. I sent them my setup and descibed my wireing layout and he said that it could have been the cause. What i don't get though is how can a servo that has to low a signal voltage cuse the Rx to go into fail safe. I only had the Y on the aileron and elevator. This setup also flew great on hte first plane for several months.

backfire

Hitec digitals on a 'Y' harness? You are lucky they are working at all. It's not the Futaba Rx; they don't work with a 'Y' harness on Hitec receivers either. Look here:

http://www.rcuniverse.com/forum/m_27...tm.htm#2710326

teletiger

I have HiTech 5625 on ailerons and elevators. Why would it work so long and then stop. Also, I'm still bench testing this stuff trying to get it to go into fail and can't. It's still working fine (minus the engine & ignition) with the batteries now down to 6.0 volts (under load).

I just want to see it happen so I can determine the cause.

backfire

I've seen the Hitec digital 'Y' harness problem myself. Sometimes it works, sometimes it does'nt. It's a marginal thing and seems to be dependent the overall installation configuration including: harness placement, length, condition, and gage; battery voltage, condition, and state of charge; and probably the condition of the servos and their operational loads.
Maybe try reassembling all hardware back in the plane except, leave one servo unplugged from each 'Y'.

teletiger

Could this have caused my pcm Rx to go into fail safe? I lost lost more than just those two control surfaces.

backfire

Not sure, but if one of the two servos on a 'Y' stopped working properly, they would be fighting each other. At this point the high current draw might bring the battery voltage down to the failsafe point. I don't really want to re-ignite the reboot issue, but look here; it might also be a factor:

http://www.rcuniverse.com/forum/m_22...tm.htm#2224694

teletiger

I've gone as far as to hold all 4 digital HiTechs on the Y's stationary and try to deflect them to create that current draw and still don't make it go into fail safe. Remeber I have dual 1600mah batteries and all HD leads and switches.

backfire

Not that it changes much thats been said, but I meant BATTERY failsafe in post #41. Recall for any further tests, that the battery failsafe is set any time the Rx voltage drops below 3.8 volts, even momentarily. It's temporarily reset for 30 seconds by moving the throttle to idle, but is not permanently reset until the Rx is turned off and then back on. Given the dual supplies to the Rx and all your checks, I don't know how this might happen, but I would find a way to monitor that Rx buss voltage closely. Looking back through the threads, I've inadvertently repeated some things, sorry.