Ok... so I'm trying to complete a new build airplane. While doing my final servo movement checks, no matter what receiver I put in, it has split second brown outs or complete reboots, .... BUT, while using a TM1000 telemetry module, I notice no voltage drop below 5.9 (6v set). It seems to be okay for the first 10-15 seconds of full throw, multi-surface movements, but then kicks in and happens faster and faster until it takes less and less servo movement to trigger.

I've tried two ESE/BEC combos (both previously used and known good 60A Opto ESCs with separate 6v BECs).

I've used complete set of analog servos, and complete set of digital servos. It seems the reboots happen more frequently with the digitals.

The receiver is NOT flashing after the brown outs, but only the multi-second brownouts. I was initially trying to use a AR600, but then tried an AR8000 for troubleshooting. I noticed on the AR8000, when the brownouts happen a red light on the rx lights up, but then goes out right away after it recovers.

The telemetry reading in the DX8 DOES NOT show any holds or lost frames.

I'm totally lost, but afraid to fly this airplane!?!?! HELP!

Have you put a meter inline and checked current draw of the servos?

No I haven't, I don't have a tool for that... I suppose I'd have to build some kind of jumper for that?

but if the rx reboots/resets, shouldn't that make the light blink?

I dont think dsmx blinks.

Originally Posted by dentalpain

I dont think dsmx blinks.

Ok, but shouldn't my telemetry tell me holds and lost frames?

The brownout detector doesn't work with DSMX. This was a point of criticism when DSMX was announced and there was a fair bit of discussion.

The reason is that DSMX is frequency hopping. The brownout detection system needs the transmitter to be on a fixed pair of frequencies. When the power is restored, if the receiver sees the same frequencies as before the brownout, it thinks the interruption must have been accidental. That's why it flashes when you fail to turn off the transmitter (which causes it to pick a new pair of frequencies. None of this works with DSMX.

Originally Posted by -= GYRO =-

No I haven't, I don't have a tool for that... I suppose I'd have to build some kind of jumper for that?

but if the rx reboots/resets, shouldn't that make the light blink?

Do you have a digital multimeter? Do you have a watt meter?

It seems weird that you are having the same problem with multiple sets of servos. Have you tried a different battery? It sounds like you have eliminated just about everything else. If you have not tried more than one battery have you run the motor under a load yet?

Originally Posted by -= GYRO =-

Ok, but shouldn't my telemetry tell me holds and lost frames?

Interesting situation.
The frame loss and hold(flightlog) data is stored in the Rx and read by the TM at regular intervals.If/when the Rx reboots the flightlog data is reset.
After a reboot flightlog data will be rezeroed.The red led does light momentarily during bootup.It is a hold indication as well.If it blinks it is indicating a hold since its last powercycle.It also resets during reboot.
Sounds like you have something else contributing to this situation.Since you are talking about it simply doing it while holding full throws I think maybe you are allowing the servos to travel until the surfces are out of travel and they are binding and stalling the servos.
Huge HUGE current draw when this happens.
Likely 5 amps or more and possibly over 10 on a full size digital servo.


You say you notice no voltage drop.What does your min/max data show after one of these events?How are you powering the TM module? A y-harness with power and TM plugged in and the other going into the bind/data port?
If your arrangement is setup so the Rx bus is powered "downstream" of the TM connection to the power the TM may not be able to see the power loss on the Rx bus itself.Put the power into the Rx on another port(s) and plug the TM into the dataport by itself.This will give a true reading of the voltage on the Rx bus itself.

The voltage may very well be holding at an acceptable level on the Rx bus until the BEC shuts off from overload too.Then it resets and powers back on.If you do nothing to correct the overload it will likely shut off and then reset and shorter intervals as it continues its cycle.

This kind of sounds like what you have going on.There are several variations on this scenario depending on how you have things hooked up but I would venture to say stalled servos are the big factor here.

Originally Posted by aerocal

Interesting situation.
The frame loss and hold(flightlog) data is stored in the Rx and read by the TM at regular intervals.If/when the Rx reboots the flightlog data is reset.
After a reboot flightlog data will be rezeroed.The red led does light momentarily during bootup.It is a hold indication as well.If it blinks it is indicating a hold since its last powercycle.It also resets during reboot.
Sounds like you have something else contributing to this situation.Since you are talking about it simply doing it while holding full throws I think maybe you are allowing the servos to travel until the surfces are out of travel and they are binding and stalling the servos.
Huge HUGE current draw when this happens.
Likely 5 amps or more and possibly over 10 on a full size digital servo.


You say you notice no voltage drop.What does your min/max data show after one of these events?How are you powering the TM module? A y-harness with power and TM plugged in and the other going into the bind/data port?
If your arrangement is setup so the Rx bus is powered "downstream" of the TM connection to the power the TM may not be able to see the power loss on the Rx bus itself.Put the power into the Rx on another port(s) and plug the TM into the dataport by itself.This will give a true reading of the voltage on the Rx bus itself.

The voltage may very well be holding at an acceptable level on the Rx bus until the BEC shuts off from overload too.Then it resets and powers back on.If you do nothing to correct the overload it will likely shut off and then reset and shorter intervals as it continues its cycle.

This kind of sounds like what you have going on.There are several variations on this scenario depending on how you have things hooked up but I would venture to say stalled servos are the big factor here.

I think you are right. I returned both the set of digitals, and the analogs today. They were the EPBUDDY.COM's OEM brand, New Power. Guess they should have been named, "Too Much Power"

I picked up a set of HS-65MGs to throw into the plane, we'll see if that fixes the problem. I've used this BEC with 4 HS-5065MGs, 4 SH-0257MGs in the past, so I'm certain its not the BEC.
I guess my final question is why no Holds or Lost Frames on the transmitter telemetry screen?

If the receiver is reset (low power) then it will have 0 because that's all the frames and holds since it's last power-up. The TM1000 does NOT remember anything, it's just a pass-through device for that data.

Andy

Originally Posted by AndyKunz

If the receiver is reset (low power) then it will have 0 because that's all the frames and holds since it's last power-up. The TM1000 does NOT remember anything, it's just a pass-through device for that data.

Andy

Andy,

then what is the point of the screen on the dx8 showing the F and H numbers if it doesn't count them? It seems to count the antenna numbers just fine (when flying on different airplane)

Thanks for reading this thread and weighing in.

-Gary

They are only valid if you power the receiver properly. You are apparently having trouble doing that with those servos.

It's the old "garbage in, garbage out" problem. Fix the power problem and you'll see good data again.

Andy

Originally Posted by AndyKunz

They are only valid if you power the receiver properly. You are apparently having trouble doing that with those servos.

It's the old "garbage in, garbage out" problem. Fix the power problem and you'll see good data again.

Andy

While I respect your answer it seems like a cop out. So the dx8 telemetry system will only count the times rx has power trouble if the rx doesn't have any power trouble?
Seriously doesn't make sense.
I understand the servos were over amping my bec and knocking power out to the rx... But that is EXACTLY the thing I want my telemetry system to tell me about so I can trouble shoot.

Or am I missing something?

Gary,

Don't look at Frames and Holds to find brownout data! That's like asking your altimeter to tell you how fast you're going. If you want to know about power problems, look at the voltage data instead.

If your power problem is so severe that it kills the telemetry, there's not much anybody can do. That's a blackout, not a brownout! It takes power to transmit telemetry, and it is being sent at the same time that your servos are being updated. You need to have adequate power there for that to happen. It doesn't have to be perfect, but it has to be reasonable.

OTOH, the fact that the numbers are reset to 0 (after being non-zero) while in flight IS telling you that you have a power problem because your receiver is being reset.

The fact that the power glitch is so bad that you aren't getting telemetry data when you try to move the servos is telling you there's a HUGE power problem. If you can change it from huge to manageable, then you can start to use the telemetry to help you debug the problems.

If you suspect that there really is a big power problem (it sounds like there is), then you might try powering the telemetry separately and see what happens. You'll need to make some special cables to do that, but you can measure what's happening on the servo bus during those problem times if you use the "flight pack" input to monitor the receiver.

I don't know your skill level. Can you figure out how to do that wiring yourself? Or do you need one of us to draw it out for you?

I'm heading to bed now. I'll check back in the morning. If you need me to draw it out I'd be happy to do that.

Andy