Miguel Santana

My Feedback: (6)

Hi to All.-
I have a jet plane with 9 Hitec digital servos & Futaba R149DP 9 channel receiver
My problem is that everytime I activate the Flaps, the ailerons servo, the elevator servos or the rudder servo glich in a way that could be dangerous.

That only happens when activated the flaps.

Details:
Flaps w/ 2 servos 5625 connected with "Y harness" to a Futaba 9 channels receiver
All other servos are 5245
2 packs of 6 volts
Ussing servos extentions with signal amplifyer from Expert Electronics
...what else?

Thanks in advance for your advises and happy new year.

Miguel

BaronSchwab

Check for some slight mix on the radio but no couldn't be that. I don't know. What TX???

visioneer_one

My Feedback: (506)

Its been reported that Hitec digitals aren't happy when connected via a Y-harness.

Disconnect both of the flap servos from the rx then hit the flap switch. See if the glitch still occurs.
Alternately - see if the glitch occurs if one of the flap servos is connected to the rx.

Lynx

Wire a large value capacitor at the base of servo connector between power and ground, if that doesn't help you may need an issolator because you're getting feedback on the signal line. Trying low value cap's between the signal line and ground may possibly help.

Miguel Santana

My Feedback: (6)

BaronSchwab:
The TX is a Futaba 9C and for sure this is not a mixing issue.-
=======================================
Visioneer_one:
The Ailerons servos are also connected with Y harness and is not causing any problem at all like the flaps servos do. A good fact to take into consideration to see if we can isolate the problem is that the flaps servos (HS-5645MG) as per the manufaturer's specifications have a ..." Current Drain (4.8V): 3mA/idle and 350mA no load operating / Current Drain (6.0V): 3mA/idle and 450mA no load operating.
All other servos are HS-5245MG with the following specifications: "Current Drain (4.8V): 3mA/idle and 180mA no load operating / Current Drain (6.0V): 3mA/idle and 230mA no load operating"
I'm running on 6.0V., so according to this everytime I hit the flaps switch is draining 900mA out of one receiver port....Could this be the cause of the problem???
I'm going to install ferrite filters right next to each flaps servo as per some friends suggestion....lets see.
==============================
Lynx :
If the ferrite filters dosen't help, I'll try the isolator.
==============================

Thanks to all, and if you have any futher ideas....WELCOME.-

Miguel

Scott Dilley

My Feedback: (3)

If that doesn't work, try installing the ferrite cores close to the reciever. And one more suggestion: if you haven't already tried it, eliminate the components one by one. Unplug one servo at a time and try activating the flaps. And one more thing, I have heard that digital servos need some break-in time to allow all the electronics to mesh well. just my $.02

JimRoss

Lose the amplified extensions and try plain extensions or cut the connectors off and solder longer leads onto the servos.

Miguel Santana

My Feedback: (6)

I did that last week, and the problem is gone.-
Something that is suppose to avoid a problem was causing one!. During test, all the tail servos stopped from working, I guess they when into failsafe mode....

Know you all know....extensions with signal amplifier from Expert Electronics are a disaster [:'(][>:]

Thanks,

Miguel

Lynx

Signal amplifiers don't work well with some servo's. No manufactor lists it but the minimum voltage and hysteres point for the detection of a servo pulse varries greatly between different manfactors. Some require rail to rail swings. Some digitals only require the standard 3.3volts of generic CMOS logic, and there's not telling what kind of circuitry is in there to generate hysteresis, apparently you ran into a condition where your servo booster was overdriving the voltage and probably confusing the hell out of the electronics inside.

JimRoss

Turn off the failsafe and try it with plain extensions.

Miguel Santana

My Feedback: (6)

Lynx,
I guess you are right about that some servos brands are sensitive than other.
The same extentions with the signal amplifiers are been use for a friend in NJ in a MIG 29 from FiberClassics, with JR servos and no problem at all.
All my didital servos are Hitec and so far I can tell they are EXTREAMLLY sensitive.
So far they don't work with voltage regulators and now this problem with the extentions.
What could be next??????
Just in case....let me consult this: I have 2 flaps servos and according to the especifications both toguether will drain 900 ~ 1100 mAh. They are connected to the same receiver channel using an standar Y harness. My receiver is a Futaba 9 Ch. on PCM mode. Do you think these Hitec servos could give me a new surprise?
My jet is schedule for maiden fly this next Sunday....
=====================
Jim,
I did that also during test and the problem persist.
=====================
Thanks Both.-