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SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

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Old 01-28-2008, 06:28 PM
  #1  
airbusdrvr
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Default SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

Airplane setup: 60 size BTE Venture, all equipment is new(about 20 flights or less in this airplane) except Futaba servo mentioned later for the throttle, five-cell Elite AA 1700mah battery, four JR DS821 digital servos(aileron(l&r), elev, rudder), one Futaba 3004 servo for throttle, JR Gold switch, AR7000 receiver that has been upgraded with latest firmware.

Today I flew four flights on a "today" charged battery(.3amp rate until auto stop using SurperNova 250 charger). After each flight, voltage was checked(6.7volts down to 6.3volts after fourth flight) using a Futaba battery checker with one amp load selected. During fourth flight I noticed a couple of times it appeared the plane had a momentary glitch. On landing I left the transmitter and receiver on and removed the wing and observed both receivers(AR7000 and its satellite) were blinking slowly. This means a voltage brownout. At this time, voltage on battery with one amp load was 6.3volts.

I know the slow blinking lights means at some point the voltage dropped to 3.8volts or below. At home with a volt/amp meter connected between the battery switch input connector to receiver and the receiver, I vigorously moved all the flight controls. I know this does not simulate flight loads, however, with two hands rapidly stirring the transmitter sticks it is hard to hold the elevator, rudder and ailerons. The voltage never dropped below 5.8volts and the amps never above about 1.5amps.

With the system powered, I pulled, wiggled, tapped and otherwise investigated everything from the battery to the receiver(even giving the receiver some good taps). Nothing caused the lights to blink.

The only solution I can think of is to replace the battery and JR switch and hope the problem is not the receiver. As mentioned above, the receiver just came back two days ago from Horizon with the following statement attached, "I did the latest firmware upgrades for the the three AR7000 rxs and three 921 rxs. A performance check was done on all rxs with everything meeting factory specs."

If any of you are Specktrum/JR system knowledgeable and have a suggestion, I'm willing to listen. Thanks
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Old 01-28-2008, 06:40 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

These are tough to fix---
the "why" is because a connection which moves -in the air - a cell which vibrates --etc., can cause an intermittant
IF the rx says " there was a low voltage occurance - I would personally accept that it was correct.
At least for preliminary trouble shooting
I would -if possible use another pack-.
Also check that throttle servo is not "bottomed out" at full throttle - things like this can cause a heavy drain.
I hate these type problems
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Old 01-28-2008, 06:48 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

dick Hanson, good idea to check travel on the throttle servo. These are the type ideas I'm lloking for.
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Old 01-28-2008, 06:56 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

Are you using the JR heavy duty switch, or the normal one? I've heard of guys going exclusively to the heavy duty switch to help eliminate the potential of losses in the switch and harness.

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Old 01-28-2008, 07:26 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

dick Hanson, I checked all servos at full throw and the amp at full throw is 0 except the rudder which shows .3 amp when holding it at full throw.

fizzwater, the switch is the JR Gold Delux Switch Harness, http://www.horizonhobby.com/Products...ProdID=JRPA001 .
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Old 01-28-2008, 07:35 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

I don't have any helpful ideas that might help you, but I agree I would try a different battery pack first. Also continue to check your control surfaces for binding. If you can get some help from a friend, you can put a little load on the control surfaces by hand to see what happens to your amp reading.

Please keep us posted regarding your findings.
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Old 01-28-2008, 07:51 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

http://www.airwildpilotshop.com/more...roduct&sku=FDC

haven't tried one yet, but have heard some good things about them. I tried to order one today, but they were out of stock [&o]
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Old 01-28-2008, 08:21 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

You might plug in a VoltWatch and get a look at what is going on with all serovs moving. You might be susprised. I have five digital futabas in my 4*60 and with a 1000mah NiCad pack, putting all servos through their moves with rappid stick movements will drop ddown into the caution zone right after a full charge. They read an instantainious load and you will see the spike current draws and how it effecting the batteries. I now top off my pack if the voltage is showing below the second light which would put my 4.8 pack at 5V. There just isn't enough steam left at that point to risk a flight.

More and more, I'm thinking that a seperate battery for the reciever would be best.

Don
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Old 01-28-2008, 08:45 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????


ORIGINAL: *JCB*

http://www.airwildpilotshop.com/more...roduct&sku=FDC

haven't tried one yet, but have heard some good things about them. I tried to order one today, but they were out of stock [&o]
This appears to be much more than the simple capacitor a few have tried for the electric cars and a few have mistakenly tried in their planes. Fat capacitor and circuitry, might actually work somewhat.
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Old 01-28-2008, 09:14 PM
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Pilot232
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

Dick Hanson,

Have you experienced any brown out since switching to A123 2 cell flight packs?

Thanks

Travis
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Old 01-28-2008, 10:08 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

No - -but I never had any before then either - using high cap NIMH
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Old 01-29-2008, 12:03 AM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

Dick,

Thanks. I just got a DX7 2 days ago. I had XPS but I just wasn't comfortable with the single antenna and no channel hopping if it encounters entereference. It has had some unexplained lockouts, (I never personally experienced any) so I went to the DX7. I'll let you know how I like it when I fly it. But the programming seems child like after my Profi 4000, by quite adequate. I will be using A123's in my receiver flight packs. I don't fly electrics. Anyway, your posts on the DX7 along with GeeBeeJim persuaded me to go Spektrum. If I really like the DX7 I will probably get an X9303 later.

Thanks again,

Travis
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Old 01-29-2008, 12:20 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

The trottle servo doesn't explain my issues with electric setups. From the bench testing I did my big drain was the activation of the retract servo. It pulled down the 4.9V Spektrum pack to 3.5 volts for a milisecond and caused it to re-boot. This would explain one crash, but not the other three for me. I suspect there was something else going on with the ESCs that caused voltage problems. It's possible that a servo got stuck or was binding, but all controls were working fine before the crashs. Since changing to the JR X9303 I haven't had any issues.


Jeff
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Old 01-29-2008, 06:21 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

airbus. I would question the 1700mah NIMH battery. You say it has AA sized cells. These cells typically have fairly high internal resistance and can have high voltage drop under load. Try something with a lower impedance. No BS batteries lists the impedance of all the cells the sell. Most volt meters average the voltage over time and don't show the actual peaks or valleys in the voltage. Good luck
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Old 01-29-2008, 08:02 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

Today I replaced the battery and battery switch harness with new. This is the 5-cell 6.0 volt battery I just removed, http://www.cheapbatterypacks.com/cel...id=ELITE1700AA . I installed a new Hobbico Hydramax 5-cell, http://www3.towerhobbies.com/cgi-bin...&I=LXNHS4&P=ML . Also, I replaced the previous JR switch with a new JR Gold Deluxe Switch Harness, http://www.horizonhobby.com/Products...ProdID=JRPA001 . Tomorrow I will fly it again and see if anything shows up. Report to follow.
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Old 01-29-2008, 10:23 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

That battery may be worse than the one you have. The more capacity they stuff into a AA cell the worse the internal resistance or impedance. Get one of the packs with a shorter fatter cell. But then again it could be a bad switch.
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Old 01-30-2008, 04:18 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

To windy today to fly. Will try again next day out at the field.
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Old 01-30-2008, 04:30 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

The 1700ma cell is an excellent cell -provided it was properly cycled when new -
The problem is- these type cells need to be charged at a low rate for first few cycles -or they may not properly "form".
the result is a battery with very short effective power life .
Typically, there is a note with them that recommends a 1/10 mah charge cycle .
Then if the battery is properly charged and formed - it will -on a test cycle , show 1700 mah required to charge and on a discharge again 1700 was discharged.
It is NOT uncommon that cells get ruined in first charge from a "fast charge' -if they were never properly formed and then the capacity is no good.

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Old 01-30-2008, 05:25 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

I'm big on slow charging(usually .3 amp) and also periodically cycling the battery to ensure it has its rated capacity. I have a SuperNova 250SS charger that can be programmed with selectable charge and discharge rates.
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Old 01-30-2008, 06:38 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????


ORIGINAL: airbusdrvr

I'm big on slow charging(usually .3 amp) and also periodically cycling the battery to ensure it has its rated capacity. I have a SuperNova 250SS charger that can be programmed with selectable charge and discharge rates.
For a 1700 mah pack 0.3 amps is not C/10 -- C/10 is 0.17 amps. It has also been my experience that my SuperNova 250S cannot be used to properly form a NiMH pack. It would always false peak and terminate charging early... I had similar poor results using a Multiplex LN-5014. My solution was to get a Sirius Charge Pro Former (forming charger) and a Sirius Super Test Pro.
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Old 01-30-2008, 07:59 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

GalenB, I guess since I've already charged and discharged these batteries using the SuperNova I am past any point of using the Pro Former. But it would be a consideration for future useage.
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Old 02-01-2008, 06:57 AM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

Flight Report: About two minutes into first flight following battery and switch change, there was a noticeable glitch inflight. I quickly landed, taxied back and did not shutoff receiver or transmitter. As I carried the plane to the table to remove the wing to look at the receiver's lights, I was expecting to see them blinking as before. But no, they were steady.

All this problem must be prefaced by saying that the airplane had 20 or so flawless flights prior to sending the receiver to Horizon for the the firmware upgrade. I AM NOT SAYING OR IMPLYING THAT THE UPGRADE HAD ANYTHING TO DO WITH THIS! It is just a perplexing situation that developed after the upgrade that has to be diagnosed.

Now my choices are:

1)continue to progressively replace remaining equipment(receiver, servos, servo extensions) until problem is eliminated. If this approcah is taken, I'm debating whether to start at the receiver and work out to the servos or start at the servos and work back to the receiver.

2)replace all the remaining items at one time and never know what it was that is causing the problem

I'm planning step 1). However, with ordering new servos, extensions etc. and my one or two day a week flying schedule, this will take a while.
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Old 02-01-2008, 12:14 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

You might disconnect all servos and stress test each-- under stall load -- with the inline volt meter.

Do you have another rx you can plug in and fly with? If you have one that has not been upgraded that could yield some valuable results in a rx swap test. Or, buy another at the LHS and if you get the same results and don't need it anymore sell it for 20 bucks less on RCU. It's a fairly cheap test that could save you time and a plane and it would at least rule out the rx being the issue.

If you were a little closer I would offer to let you use one for a week to see if it changes anything. Sorry, I'm in Cali and the round trip would take weeks.

To date I haven't had a glitch with the spektrum 7000 rx and am awaiting arrival of my first batch of upgraded receivers.....I LOVE THIS STUFF?

Good luck. I hate these kinds of issues but I would do a lot of stress testing before replacing anything.

AA cells usually don't deliver the amps/volts due to high internal impedance. Try nobs or cheapbatterypacks and get a cell that can carry a 20 amp load. Elite makes a 1500 that can do 20 amps. The big brand stuff just doesn't cut it. Also, 20 or 22 guage wire from batt to to switch to rx is a must even on a small plane.
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Old 02-01-2008, 01:40 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

Do you have the Spektrum Flight Log? That gizmo should be able to tell you extactly what is going on with your voltage and your RF link...
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Old 02-01-2008, 02:30 PM
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Default RE: SPECKTRUM BROWNOUT-NEED IDEAS TO SOLVE??????

A possible way to rule out battery problem is to add another pack of similar type/capacity. I am using 2 X 1100mah nicad packs on 30% sacle with 5 digital servos and a futaba PCM receiver. Since it never goes to false-safe mode in flight, I am pretty sure the receiver voltage stays above 4V.

If this problem shown up only after the firmware upgrade and noththing else has changed, it is almost certain that the upgrade caused it. Give the vendor a call.
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