JR Radio PRoblems

Help Me!

I have a JR XF-622 Radio that I am using with a JR Receiver Piccoboard. At a certain point in the throttle travel it causes the servos to whack out. This also happens at a certain point on both the aerilon and elevator channels too. It is not a glitch. It happens at the same spot every time. If you guys khow anything about this I would love any suggestions. I cannot find a resonable explanation for this. This problem broke the pin on the swashplate so if any of you guys have some extra you would like to sell/give away. I would appreciate the help. I am going to CA some CF rod to repair it for now. But I really need to know if there are known problems with this combination or am I just missing something. It makes it impossible to do anything with it at this point.

Also, how many cells are required?. Is it 7 minimum with the piccoboard\receiver combo. Is 6 cells too few? Could that be my problem?

Thanks
David

This is my first pic. I have another I bought quite by accident with the futaba board. So I wonder if I will have similar problems.


Come on guys, I cannot be the only one to have experienced this and I want to fly it. Could it be from low voltage?
[This message has been edited by davidg51537 (edited 10-28-2001).]

[This message has been edited by davidg51537 (edited 10-28-2001).]

I think it's broken and you should give it to me

Is your transmitter set to Heli mode.?

Use 7 cells David and report back.

re: Broken Swashplate Pin, I drill a small hole through the swashplate then poke a pin through from the inside and trim to size the CA and you will never have to worry about this again.


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Regards,
John VHJM010700




[This message has been edited by Mantovani (edited 10-29-2001).]

I found my problem(s). The first being that I was using a dual conversion crystal wherre it should have been a single, and my tail motor burned out.

Necessity is the mother of all invention. I will preface this with the fact I have have extensive electronics experience. I went to the local hobby shop and they only had dual conversion crystals in the standard size. I am an impatient cuss, so I bought a GWS micro single conversion crystal and soldered it to the integrated receiver. Didn't I read somewhere that it is a berg 6 channel unit? I almost just started using the GWS micro reciever I already had, but I wanted to make this work. I will order the right crystal tommorrow and remove the other when it arrives. Then I turned to the tail motor. It had burned out today(mind you, I bought this Friday evening from someone local who could not fly it so it maybe had 3-4 runs on it), I cracked open the case and repaired the windings so it would run again. Why does the Picoboard burn these out so easily? I will have to investigate that. I would like to know what people are using for seperate items. I think I will retain the receiver(for the CP upgrade I know I will do), but I would like to know what Speed Controls people are using and what Gyro.

Tomorrow, I am going to buy some NiMH AAA rechargebles to build a pack with. Twenty bucks. I will start building my own packs to save a bit.

Alas, if you know anyone with a bad piccoboard, I would like to aquire it and see if I can start fixing them. With my background, I should be able to.

Thanks
David

[This message has been edited by davidg51537 (edited 10-29-2001).]

[pgoelz]

The tail motor is fragile because it is being used beyond its design limits. In addition, there are a couple other things going on.

First, the motor can be severely overloaded in the event that the tail rotor is blocked. This can easily and very quickly melt the tiny brushes. If you crash, get off the power IMMEDIATELY.

Second, the way the Piccoboard (and most other ESCs) controls the power is very hard on the brushes. The controller applies full battery pack voltage to the tail motor but switches it on and off as needed to maintain the desired power level. The average voltage to the motor varies from 0% to 100% in response to the duty cycle. However, the fact that the applied voltage is the full battery pack voltage causes additional brush arcing and wear which increases as the applied power decreases. Since we hover the Piccolo with the tail motor somewhere around 50% power, we end up using the tail motor at a power level that causes heavier than normal brush wear. This effect is manageable if you fly on 7 cells. However, if you graduate to 8 cells the brush wear increases significantly, and the motor will not last anywhere near as long.

The cure on 8 cells is to run the tail motor off a variable source of pure DC instead of pulse width modulated DC. This is not possible with the Piccoboard or most other ESCs. However, that is exactly what the JMP HF9 controller does. It is in effect a tiny variable voltage switching regulator that utilizes an L/C output filter and produces nearly pure DC. This is possible due to the much higher operating frequency. This controller has DRASTICALLY increased my tail motor lifetime on 8 cells. Before I installed the HF9, I was getting maybe 10 flights per motor on 8 cells. After installing it, I have yet to have a failure after hundreds of flights.

See my web site (below) for lots of additional info.



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Paul Goelz
pgoelz (at) eaglequest (dot) com
AF010 brushless motor, 8 cell NiMh, collective pitch modification
Visit my Piccolo web page
And check out the Troubleshooting guide
Also, see my flybarless collective pitch Piccolo page