tattle tale blinks green LED with glitches in flight - RC Groups
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Mar 28, 2017, 03:44 AM
Garland
Ghia's Avatar
Discussion

tattle tale blinks green LED with glitches in flight


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For many years I skipped over RC planes and just flew RC helis. So I bought a LT-40 kit and have a local instructor teaching me to fly airplanes.

This LT-40 built from a kit has a XPS 8 chan RX and tattle tale installed. Futaba 8UHP radio, 5 cell 2000mah nimh pack, my failsafes are set to eng idle- slight rudder left-slight elevator up.

I have never seen the tattle tale change any color except green on this plane, and pack was fresh charged. So on the previous flight once or twice it would "blow" (windy) the plane direct opposite my commanded right turn. We thought it windy tricks or something.

Next flight it yanked hard left when I wanted right turn on the buddy box (futaba 4 channel TX) and I knew it wasnt me or the wind! in fact engine stalled for no reason and instructor dead sticked it in. It had a blinking green LED.

So we bound this plane to my spare futaba 9c radio and its XPS module. Instructor alone flew plane and he said he felt a twitch in flight. Plane landed blinking green. but he said it flew beautiful so its not the wind/airframe.

I'd like to send all my XPS gear in for a check up and my futaba radios to repair service. Im guessing that I have owned my futabas going on 20 years and I hope they can be fixed but they sure have been good till now.

I dont want this LED to change from green OR blink green on my helis or planes EVER! Its either a futaba prob or XPS and I'd like both fixed so i can get back to my happy place. i have been XPS happy since 2008.
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Mar 28, 2017, 09:23 AM
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FlyingW's Avatar
Garland,

I just took a look at the Tattletale documentation and I think it is saying that the voltage remained above 4.51v, but there was some problem with the receiver getting valid signals to control the servos.

Have you checked the imfamous connector pins in the RF module bay of the Futaba Tx? I've had to re-solder all of mine over the years.

Good luck finding and solving the problem - the LT-40 is a great airplane.

Paul
Mar 28, 2017, 11:21 AM
The only way the for the Tattletale to blink green is due to an intermittent PWM pulse, which is generally caused by a loss of power. It sounds like you might have a faulty switch, servo extension, or solder/tab issue on your battery pack.

When this occurred, what was the LED on your XPS receiver doing?

I would recommend moving things around in your plane while it is powered and see if you can reproduce this issue (engine not running). Grab your battery pack and twist it a bit. I have seen plenty of Nimh packs with bad tabs. The bottom line is that even a complete transmitter or receiver failure can not cause the Tattletale to flash. That can only occur due to an intermittent connection.
Mar 28, 2017, 01:12 PM
Garland
Ghia's Avatar
Quote:
Originally Posted by JimDrew
The only way the for the Tattletale to blink green is due to an intermittent PWM pulse, which is generally caused by a loss of power. It sounds like you might have a faulty switch, servo extension, or solder/tab issue on your battery pack.

When this occurred, what was the LED on your XPS receiver doing?

I would recommend moving things around in your plane while it is powered and see if you can reproduce this issue (engine not running). Grab your battery pack and twist it a bit. I have seen plenty of Nimh packs with bad tabs. The bottom line is that even a complete transmitter or receiver failure can not cause the Tattletale to flash. That can only occur due to an intermittent connection.
Ihave the tattle tale mounted exterior on plane and cant see Rx in flight. I do have tattle channel programmed to cut servo signal if failsafe along with left rudder and up elev, along with cut throttle....i had to have felt the failsafe kick in!

JD of course I check my batt/switch but you dont suspect my futaba gear or XPS gear? It happened on 2 different radios/modules. I am worried about my module pins! Im thinking sending Futaba off to radio south to be sure.

JD shall I send in all my XPS gear to you as well? I dont understand how it cant be a module/futaba pin failure cause tattle to blink green?
Mar 28, 2017, 03:33 PM
OK, if you programmed failsafe to turn off the PWM output for the channel the Tattletale is plugged into, then yes, a failsafe would make it flash! You can test this by turning on your system, and then turning off the transmitter. The LED on the Tattletale should start blinking. When any of the transmitter's module pins has a bad solder joint, it can intermittently break connection. That's just like turning your transmitter off! It could be your 9C module pins. These are very easy to fix. Just remove the XPS Tx module, and open up your transmitter. You will see a circuit board mounted to the back half of the case. That board has the module pins. Just resolder them and put your Tx back together. That's it!

What does a range test give you for range? You should look at your XPS Tx module's antenna connector. The center pin should be slightly above or flush with the gold housing. If the pin is recessed, it's broken and that would cause your problem for sure. If you can easily bend your 2.4GHz antenna, or it flops around on its own, then the coax is broken and that would cause your problem as well.

We can certainly look over your system and test it.
Apr 02, 2017, 08:52 AM
Garland
Ghia's Avatar
Ok I have dug a lil more into my plane issue but its still not solved yet. I just ordered 2 new XPS nano RXs, not to replace my 8 channel RX in the plane, but I realized I used up all my old school XPS 8/10 channels in helis and planes already will need more RXs anyway. I have never seen the nano Rx everyone been raving about, so now I got 2 finally! I been meaning to buy some of these.

So all my current XPS gear is going off to Arizona for a health check. Im not saying its the cause of my issue but I bought XPS in 2008 so I think its about time for the pros to look it all over (modules and 8/10 channel Rxs).

My plane has a low self discharge 5cell nimh pack Tenergy centura cells. After reading they dont seem to like high vibes or high current loads. Not good for RX pack even though this is a trainer plane. I didnt formation charge at 1/10 C on its first charge either. Its coming out, I will reuse those cells in a TX pack as they are EXCELLENT for radio batteries.

I didnt want to mess with A123 life balancing in the plane, and my 2300ma cells are HUGE! Im back to this idea though, as they all the cells I have right now. I'd like to use (2) 2 cell packs parallel into 8 chan RX. My plane needs nose weight anyway.

I will check and resolder my 8U Futaba module pins because during the last range I thought it weird I didnt get as far as normally do with my 600mm helis using a Futaba9C and its XPS module. I. Usually get tired of walking and cant lose control of servos with module button held.

Question?? Is the range check pass or fail "owned" by the XPS module or its Futaba radio? Thanks for all the help.
Last edited by Ghia; Apr 02, 2017 at 09:06 AM.
Apr 02, 2017, 11:20 AM
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FlyingW's Avatar
If control is intermittent at close range than it could be the transmitter's connector pins or the center pin of the transmitter's RF module antenna connector.

If control is solid but does not go far enough in a range test it could be interference caused by wires, servos, or other metal objects too close the receiver antenna.

If the connectors are all good, and there is a good power supply then there is a chance it could be XPS parts. That's easy to identify by swapping with another Rx or Tx module.
Apr 02, 2017, 11:33 AM
Range is solely controlled by the ATX module and antenna. If range is short, it's either the center pin in the antenna connector, antenna, or the Tx module RF has an issue.

You can determine if the module pins are making intermittent connection by looking at the Tx module's LED. It should flicker consistently, and never turn solid or change its pattern.
Apr 02, 2017, 09:12 PM
Garland
Ghia's Avatar
Radio Glitchs! Sig Trainer starts Breaking Bad in flight! (3 min 30 sec)


I caught some of those glitches on vid I think. Can ya'll watch and see what ya'll think? thanks
Apr 03, 2017, 10:16 AM
No matter what brand of 2.4GHz system you use, it is physically impossible to get uncommanded input due to the RF link. The receiver either gets good data, or no data. You can never get a hard left or hard right like the video shows due to the RF link. What can cause that though is loss of power. When servos don't have any holding force, the plane can meander in the sky.

If you have an older version of the 8 channel reciever firmware, it won't blink on reboot. You can test this by powering everything on and then powering off the receiver and then powering it back on. The LED should blink orange if it has the reboot warning. If not, then there would be no way to know for 100% sure that this is a power problem, but it certainly looks like it.
Last edited by JimDrew; Apr 03, 2017 at 11:51 PM.
Apr 03, 2017, 01:06 PM
Garland
Ghia's Avatar
I too think its the nimh I used that day. But since Im leaving on vacation as we speak and dont need my XPS gear for awhile it is on its way you today JD. Just a check up as I love my XPS system which has been solid in my helis since 2008. I use dual A123 packs there though. This is my first plane built from a kit. Im learning the airplane side.

I will follow up on this once I get back. Thanks JD!
Aug 05, 2017, 08:56 PM
Garland
Ghia's Avatar
Ok I will update this:

I got back all my gear from xps a while back. I assume all was good since XPS didnt say of any probs on ALLor any of my gear they inspected.

So I happily put my XPS gear back in service I have been flying my helis on my 9c radio many times since then and they been been rock solid on their 8 and 10 channel XPS RXs! Im very happy!

A bud flew my trainer plane for the first time today and it glitched in flight! My plane now has dual A123 2300mah packs in parallel, XPS 8 channl RX, tattle tale with its PPM signal turned off and elev/rudder will kick up and left a lil during failsafe. Fresh charged batts and plane flew great doing loops rolls but it definatly went into failsafe once as he felt it in flight. The tattle blinked green on landing which is what I want, it verified the failsafe condition.

I guess I cant fly the older 8channel rx in a plane. I dont know what its doing, or why, but I will replace it with a brand new nano RX. Im kinda tired of this glitch, especially after I got all my gear back from XPS!

What if the new nano glitches? What then??
Last edited by Ghia; Aug 05, 2017 at 09:03 PM.
Aug 06, 2017, 11:42 AM
It could be the location of the receiver, or moving wires around the antenna. We had one customer that was having a failsafe occur, but only while doing a snap roll at the top of an upline. The problem was he had aileron extensions that were just laying loose in the plane. When the snap occurred, the wires (extensions) would pass over the reciever antenna which changes the antenna tuning, resulting in loss of signal. He added some clips to hold the wires against the side of the fuse and the problem went away.
Aug 06, 2017, 10:02 PM
Garland
Ghia's Avatar
You might have found my issue JD as I dont know what to do with all these wires in a plane! Here is a airplane pic how its always been flown with its wires:

Also a pic of my XPS heli installation
Last edited by Ghia; Aug 06, 2017 at 10:43 PM.
Aug 07, 2017, 05:09 PM
Those installations look fine. You just don't want wires moving over or under the antenna. If the wires are moving around where they plug in, that is fine, you don't want wires that have the ability to physically touch the antenna.

Another possibility is that there is a power outage occurring. The TattleTale could reset to green and flash on power up if there was no signal present. Try this - turn on the system so you can move the servos. Now, power off the receiver, and then power it back on. You should see that the LED on the receiver is flashing orange (reboot notification). The Tattletale LED should be green, but could be flashing. Have you noticed the LED on the receiver ever flashing while the Tattletale was flashing?


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