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Old Oct 20, 2009, 06:19 AM
Don't leave it Stock
mrfliboy's Avatar
USA, IL, Round Lake
Joined Feb 2004
2,510 Posts
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Vapor brick goes south on me

I recently transplanted the sukhoi 8mm motor into my Bill Lowe Micro bird to give it a needed boost in power. I'm running a TriTurbo DD prop and it made all the difference in the world.

1/2 throttle is normal flight with a occassional burst of full power to get me out of those not so great spots. After the 3rd flight or so I noticed a glitch per say with the throttle, upon applying throttle the motor would give a short burst, led light goes out and nothing. A few moments later all would be fine. After this occurred twice, nothing on the brick would work.

I've swapped out battery leads, (they were a tad loose) and have attempted every type of bind procedure possible. The brick will flash approx 15-20 times and no bind no nothing. The servos are not binding at all.

Now this is a older brick maybe 2 yrs or so. I have not done amp draw with the new setup yet either. Question being did (if) excessive amp draw kill my brick? Or was it time for my brick to die. It has had a great and useful life.

Thanks for any and all replies.
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Old Oct 21, 2009, 02:52 PM
Software always has bugs
United States, TX, Missouri City
Joined Nov 2008
262 Posts
Quote:
Originally Posted by mrfliboy
I recently transplanted the sukhoi 8mm motor into my Bill Lowe Micro bird to give it a needed boost in power. I'm running a TriTurbo DD prop and it made all the difference in the world.

1/2 throttle is normal flight with a occassional burst of full power to get me out of those not so great spots. After the 3rd flight or so I noticed a glitch per say with the throttle, upon applying throttle the motor would give a short burst, led light goes out and nothing. A few moments later all would be fine. After this occurred twice, nothing on the brick would work.

I've swapped out battery leads, (they were a tad loose) and have attempted every type of bind procedure possible. The brick will flash approx 15-20 times and no bind no nothing. The servos are not binding at all.

Now this is a older brick maybe 2 yrs or so. I have not done amp draw with the new setup yet either. Question being did (if) excessive amp draw kill my brick? Or was it time for my brick to die. It has had a great and useful life.

Thanks for any and all replies.
If nothing is powered up (even LED light), I would check on the linear regulator on the board (3 pin component) that sits very close to the input power wires. I expect that IC was burned.
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Old Oct 21, 2009, 03:02 PM
Fly long and land softly
Jim_Marconnet's Avatar
Madison, Alabama USA
Joined Oct 2005
5,390 Posts
I've had about 5 of the Vapor bricks go bad this way. I call it "Won't ever bind again". They worked just fine for many flights. Then down came the Vapor in the middle of an otherwise uneventful flight, with nothing working; and it would never ever bind again. My LHS has cheerfully replaced all of them, but they are getting less cheerful!

Jim
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Old Oct 22, 2009, 05:42 AM
Don't leave it Stock
mrfliboy's Avatar
USA, IL, Round Lake
Joined Feb 2004
2,510 Posts
Quote:
Originally Posted by MTDV
If nothing is powered up (even LED light), I would check on the linear regulator on the board (3 pin component) that sits very close to the input power wires. I expect that IC was burned.

Led light will flashh approx. 15-20 times and than goes out.


My main question is will overamp drawing the board cause binding failure?


This board btw has probably anywhere from 100 to 200 flights. It might have been time to die is all.
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Old Oct 22, 2009, 12:46 PM
Software always has bugs
United States, TX, Missouri City
Joined Nov 2008
262 Posts
Quote:
Originally Posted by mrfliboy

My main question is will overamp drawing the board cause binding failure?

.
Theoretically, simple no, but it's possible because of the "back-fired" of the motor, and here is my explanation.

The bigger is the motor, the higher current it will draw from the battery. When the battery is overloaded, it's voltage will drop. The brick will be reset at its threshold. During the reset time, the GPIO of the micro controller is set at an unknown state. if the motor was running at high RPM, and the micro controller going to reset, the transistor may be at an open-state. The motor becomes a generator which will feed the voltage back to the battery. The instantaneous voltage from the motor may be higher than the maximum voltage of the regulator, so the regulator will fail to regulate the voltage to the micro controller, and the high voltage may damage the micro controller which causing the brick to be death.
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Old Oct 22, 2009, 01:00 PM
Don't leave it Stock
mrfliboy's Avatar
USA, IL, Round Lake
Joined Feb 2004
2,510 Posts
Quote:
Originally Posted by MTDV
Theoretically, simple no, but it's possible because of the "back-fired" of the motor, and here is my explanation.

The bigger is the motor, the higher current it will draw from the battery. When the battery is overloaded, it's voltage will drop. The brick will be reset at its threshold. During the reset time, the GPIO of the micro controller is set at an unknown state. if the motor was running at high RPM, and the micro controller going to reset, the transistor may be at an open-state. The motor becomes a generator which will feed the voltage back to the battery. The instantaneous voltage from the motor may be higher than the maximum voltage of the regulator, so the regulator will fail to regulate the voltage to the micro controller, and the high voltage may damage the micro controller which causing the brick to be death.

Great response Thanks
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Old Oct 22, 2009, 01:02 PM
Fly long and land softly
Jim_Marconnet's Avatar
Madison, Alabama USA
Joined Oct 2005
5,390 Posts
I'm not sure what MTDV said, or what it really means. Perhaps it takes a rocket scientist (of the electronic variety)!

All of my 5 Vapor brick failures occurred at a medium speed, flying along in a generally straight line, not doing a climb, dive, turn, or other manuever. The last time in the world I'd have expected the brick to die mid-flight. As I remember it, 4 times were while flying outside, once while flying in a large indoor aerodrome. None were fresh off the charger, nor near LVC.

Jim
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Old Oct 22, 2009, 02:45 PM
Software always has bugs
United States, TX, Missouri City
Joined Nov 2008
262 Posts
Quote:
Originally Posted by Jim_Marconnet
I'm not sure what MTDV said, or what it really means. Perhaps it takes a rocket scientist (of the electronic variety)!

All of my 5 Vapor brick failures occurred at a medium speed, flying along in a generally straight line, not doing a climb, dive, turn, or other manuever. The last time in the world I'd have expected the brick to die mid-flight. As I remember it, 4 times were while flying outside, once while flying in a large indoor aerodrome. None were fresh off the charger, nor near LVC.

Jim
In your cases, failure would be in component.

By the way, a burned motor would also cause the failure of the brick because the cooper wire shorted together in a burned motor. This short draws very high current, and that exceeds the maximum rating value of the transistor. That causes a failure in the ESC circuit.

If you have power to the board but the brick does not bind, I would think the failure would be somewhere in the RF portion. That caused the signal did not get into the micro controller, and binding could not be processed.
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Old Oct 25, 2009, 03:18 PM
billyjim
Cullman, AL
Joined Jun 2007
914 Posts
Brick death clue

My experience is with the older bricks (Cessna, Citabria, Ember1). After 3 summers of using these bricks in my scratch-built foamie WWI bipes, working thru maybe 7 or 8 bricks, I may have stumbled on at least one mode of brick death.

I've had only 1 NBA brick, but 3 others just died "for no apparent reason." I noticed one gave off that acrid smell that all electronic techies recognize as component 'frying' -- usually an IC. When I removed the brick from the foamie fuselage I noticed a deep, slightly brownish, melted section of the fuse right under one of the smd chips. Noticed nothing else.

Another brick, before it died, fortunately just before an ROG takeoff, behaved as follows: as I gave it a pre-flight test of rudder/elev/throttle I noticed the rudder jammed full left, the elev would not respond, nor would the motor.
Never checked the brick thereafter -- just threw it in the junkpile.

Then 2 weeks ago, same thing at the same time. This time I immediately unplugged the Lipo, and took everything home.

The first thing I did was to momentarily plug in the lipo and try the rudder control again -- no servo movement. I quickly unplugged the lipo.

Then on close exam I noticed the rudder servo's large white gear was way forward of its usual position, barely meshing with the small white gear of the servo motor. And I could slide the black pushrod connector forward and back a mm or so. It was then I noticed that the stopper at the back end of the gear/pushrod connector/metal shaft was pushed way aft, almost off the shaft.

Then I tried, manually, to spin the large white gear -- it wouldn't budge -- jammed. AHA!

Next, I pushed the gear/slider/shaft assembly back so that it properly meshed with the servo motor gear. Then I pushed the rear stopper forward, locking the shaft into its correct position. Then I epoxied the stopper in place.

Then the big test. I re-plugged in the lipo, and gave the rudder stick a push -- presto, full response. Same with elevator and throttle. I had brought the brick back from the morgue!

Tentative conclusion: if for some reason one of the servos jam, there's gonna be a stall overload, and eventually pushing a PCB component into failure.

What do y'all think of that explanation?

Bill
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Old Oct 25, 2009, 06:03 PM
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Jim_Marconnet's Avatar
Madison, Alabama USA
Joined Oct 2005
5,390 Posts
Bill, certainly a plausible explanation. But all 4 or was it 5 of mine failed midair, flying medium-speed, not doing any sort of manuever or anything!

Jim
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