FenderBean

I was wondering if anyone had any experience with this unit? i plugged mine in today any it was pretty simple once i figured out the menu but for some reason everything plugged into it constantly twitches. My servo connected to my two valve jumps a little constantly and same for the brake valve servo. The brake valve servo will go nuts when i get to one of the settings and will not stop until i remove power. When I power it back up the brake servo will just twitch like the other servo, unless i go through the brake settings again and then it goes crazy again. I thought maybe it was the hitec servos but I plugged in a futaba and same issue. I can manually move the valve but when I flip my gear switch the valve doesn't move.

Any thoughts? Bad unit?

lightningmcnulty

My Feedback: (11)

Its usually caused because they don't play well with digital servos and the servos struggle to find their targeted points, you can solve it with analogue servos

FenderBean

They Only Do It When Plugged In To The Sequencer And I Tried Both Analog And Digital Servos.

Edgar Perez

My Feedback: (13)

I'm using one with no issues. Defective?

vinnyjet

My Feedback: (39)

mine works fine have it in my eurofighter using jettronic valves for gear/brakes/doors
vinny

FenderBean

Okay I Will Contact Todd To See About A Replacement. I Have Seen The Center Issue And This Is Much Mor And The Brake Servo Going Crazy Is Suspect. thanks

mr_matt

My Feedback: (10)

Maybe the frame rate from the receiver is too high? Can you slow it down?

FenderBean

I Will Check

DiscoWings

My Feedback: (76)

I have found that jettronics stuff and airpower/dreamworks rebranded stuff does not work well with each other.

FenderBean

To the guys who use it without issue what receiver/radios are u using?

ravill

My Feedback: (11)

Is it the EV5U? I have four of them and they work fantastic with a 12x, DSM2.

FenderBean

no I have the sequencer/failsafe
http://www.dreamworksrc.com/catalog/...tion-Sequencer

Len Todd

Read about this today. The faster frame rate will not work well with analog servos. You can change this to a slower rate. Also, one of our jet guys has a twitchy nose wheel, all of a sudden. It actually proved to be the transmitter was acting up.

FenderBean

Todd those same servos work just when plugged into the same receivers work just fine. I also plugged in a BLS 175 and another digital servo to check and it had the same thing. There is nothing wrong with the transmitter.

Len Todd

Did you try a lower Frame Rate and then try a different transmitter?

Our guy here pooh poohed a transmitter problem when I first suggested it. After all, How could his DX-18QQ be messed up? He tried another DX-18 and the problem went away. Something was messed up with channel 8, in his case.

In the DX-18 Manual, they talk about the higher frame rate negatively affecting analog servos. Also, in the past, I have experienced problems mixing in analog servos with digital servos. Although, it was probably just a frame rate fix, I did not know about this fix at the time. I just went to all HV digitals. Problem solved. Your case may be a bit different. So, ...

Good luck!

vinnyjet

My Feedback: (39)

futaba 14mz 14 ch rec

FenderBean

I tried different channels and different receivers and its the only thing that glitches. The servo speeds are super slow even with everything turned up in the sequencer the gear valve moves so slow that it takes about 15 secs for the servo to go from open to close. the door servos work normal speed. Its just not acting right, some times I hit the gear switch and the valve servo doesnt move and I flip the switch again and it finally moves.

Len Todd

Given what you have provided so far to trouble shoot it I would:

Try powering the sequencer directly using a servo programmer to drive it? If it works with the programmer driving it, something other than the sequencer is messed up.

Put a servo programmer in the circuit to read the resolution being sent from the rxer? Is it a smooth readout as the Rxer works the Sequencer? I mean it will change resolution but does it change smoothly?

Put a current meter in the circuit to see how much current it takes to operate. Is it within Spec?

Check to ensure do not have one harness connection reversed.

Check to ensure the grounds are all common in every servo and the sequencer?

Check the Battery fully charged? I assume you are using a battery with~ 6 VDC and the sequencer is supposed to work at 6 VDC. Look for that voltage at the sequencer.

Check how much current is being used at the battery when you work the sequencer with the Rxer. Make sure the battery can deliver that much plus all the other loads. Maybe need a power distribution unit?

Check the voltage at the Sequencer at rest versus when working? Should be close to the same. If not, then there is may be an excessive resistance in the circuit.

Without it in front of me, that is all I can tell you about how I would go at it.

FenderBean

I have tried different leads, voltage is 6 volts and I did have a amp meter hooked up all was normal except when the servo jumping occurs, it would jump around. These thing are pretty straight forward and if its this hard to get something so simple to work I would rather not use it. Im using the unit with a Robbe batterybacker its plugged into the on board channel set to 6 volts. I also hooked it directly to two different receivers at 6 volts using three different servos, Im going to send it back and have them check it. I hope i can get it working nnot any other items like this one out there, dual air gauge, fail safe and sequencer.

Springbok Flyer

I agree, they are fantastic, wish I could find more of them as it seem AirPower jas stopped making them.....

Jan

mr_matt

My Feedback: (10)

Did you check the frame rate? Frame rate is likely set in the TX so if that is the problem swapping receivers won't help

Len Todd

I mentioned that earlier. I assumed he did check the frame rate. It clearly states in the DX-18 manual that analog servos may not work consistently with the 11ms frame rate that is standard with DSMX. Also Ravill is using DSM2 and has good luck. Does DSM2 even offer the ability to use the 11ms rate of DSMX?

FenderBean: What Frame Rate are you using? You can change frame rates from the transmitter's System Setup menu. Did you try the slower rate (i.e. 22ms)? I also assume you tried a different transmitter, ... too. Right?

wfield0455

My Feedback: (7)

Since high frame rates were originally implemented to improve performance for extreme 3D helicopters, the higher frame rates are generally only implemented on some receiver channels on Spektrum gear, ones generally associated with cyclic controls and rudder on helicopters. While some radios may use high frame rates on all channels, Andy Kunz (a Spektrum developer) has stated that Spektrum gear does not pass high frame rates on all channels.

FenderBean

The Frame Rate Is Changed In The Radio Based On The Selection Of The Receiver. Fasst, Fastest Selection, I Will Check To See If There Is Another Way. With My Current Receivers I Can Change Betwee Two Resolutions. That I Know, It Does The Same Thing With My Dx7 Radio.

Len Todd

Frame Rate and Resolution are two different parameters. Frame Rate is basically how fast a digital frame is sent. Resolution is loosely the servo position setting that is encoded in the digital frame. Each frame has a servo setting for each channel, among other data. A servo with a higher a resolution band (e.g. 2048) will have more discrete position changes. You get less movement per increment of resolution change. On a throttle for instance, the more resolution you can take advantage of the smoother the throttle response.

You are right that not all channels have the same frame rate and resolution. For example, on a DX-18:

Channels 1-10 are typically set default to 11ms Frame Rate. If X-plus is activated, channels 1-10 are set back to 22ms or in either case, you can manually select 22ms. Resolution of channels 1-10 is 2048.

Channels 11 & 12 are automatically 22ms but still have 2048 resolution. One can not change channels 11 & 12's Frame Rate back to 11ms.

Channels 13-18 have a 516 Resolution and variable frame rate latency from 22ms to ~88ms. This is why one never uses channels 13-18 for a control surface.