Matagordababy

I'm stumped, and would welcome some advice. My youngest Son just completed his first large scale Cap-232 with an ST-2300 for power. He's 15 and FAR outflies anyone in our little town, but his building is still a bit erratic. Don't know if this is the source of the problem or not...

Radio Checks show severe Servo Chatter all throughout the machine except the Throttle Servo.

Before I go further, he uses the same Transmitter, Frequency, and GWS Servos in his Hangar 9 Super Stick with zero problems.

Equipment:

JR XP6102 Transmitter, JR 7700 Receiver, GWS SO3T-2BB Servos (6), and 3 Brand New various Batteries to run the system, to include (for trial purposes) JR Batteries.

Three different attempts have been made to sort this out, ALL with Freshly Charged On-Board and Transmitter Batteries, and we are still at square one. Let me tell you what we've tried (NO Change in the right direction with any of these steps or processes):

1. New Receiver
2. New Receiver Crystal
3. Three Different New On-Board Batteries
4. Disconnecting everything from the original (and again with the New) Receiver except Battery, plugging in each Servo one at a time, by itself
5. Disconnecting the Charge Port and On/Off Switch from the Receiver (both again) and powering the Receiver and Servos (individually) with direct Battery Power
6. Relocated to outside to ensure we weren't picking up RF interference from something in our home - no change
7. Rerouted the Antenna
8. Plugged the SAME two Receivers and all Three New, Hot Batteries into his Super Stick one at a time as a function check - perfect, no issues.

I'm all for removing all RC Gear and Bench Testing it, but my Son got a bit ahead of himself and CA'd down the major Access Cover, so no dice unless I take a blade and saw to it.

When I say "Chatter", turn your airplane On without the Transmitter also being On - this is the same uncontrollable "Chatter" I'm talking about. This thing has a problem!

Any Ideas, Gents?

Matagordababy [:@]

proptop

My Feedback: (8)

Ah...that last statement you made...

"WITHOUT the transmitter also being on"...
There's your problem...the receiver can pick up extraneous signals w/o the Tx. being on.

Standard practice is to always turn on the Tx. first...and off last.

Do things work OK when you do that?

It's not uncommon for servos to twitch uncontrollably when just the airborne switch is on...no transmitter broadcasting.

On some extreme occasions, servo damage can happen...like stripped gears...

If your shop has florescent lights...they can sometimes cause problems with 72 mhz.

Matagordababy

Thanks for the input, but that's not it. I was only using the Xmtr Off to illustrate the sort of Chatter I'm seeing. Guilty - I've certainly done it before, but this is not the case here. Transmitter On, then Plane, reverse for shut down.

Keep 'em coming guys - there's a solution, I'm just not smart enough to know the source of the problem...

Matagordababy []

proptop

My Feedback: (8)

Oh...sorry...I must have mis-understood...
With 48 years at it, you definitely are an experienced flyer...you've tried about everything I would think of.

Would you happen to be using 5 cell "6 V." batteries?

Matagordababy

No Sir, 4-Cell 4.8V Batteries are what I've always run, though to be perfectly honest, I know so little about electrical power it's scary. Should I be looking at another Battery type?

Matagordababy [:-]

proptop

My Feedback: (8)

No...I was just thinking...sometimes when a 5 cell / 6V. pack is used, and fully charged, it can cause the servos to twitch a bit until the voltage drops a little.

You've got me scratchin' my head here too...

Maybe someone else will come along with a different viewpoint...

It seems a bit hard to believe that it could be all 6 servos that could be the problem?

Matagordababy

You just gave me an idea - I've four Brand New Sport JR Servos in a box - it's easy enough to check to see if there is a compatibility issue with the GWS Servos and this JR Transmit / Receive system. It seems far fetched though as I've GWS Servos installed in other planes, and we only run JR here..

None the less, eliminating potential / possible solutions will eventually lead us to the right one. If need be, I'll be as tender as possible with my blade and saw and disect his machine, though he keeps looking at me like I've lost my mind when I bring up this step...

Matagordababy

Steve Percifield

My Feedback: (14)

Are you doing this in the same room? Just thinking out loud.... Take it outside and try it.

Matagordababy

Yessir, sure did with the same results. I appreciate the input though - keep 'em coming!

Matagordababy

proptop

My Feedback: (8)

Yeah...compatability was the same word that crossed my mind...maybe they're not "talking" to each other properly?

Ya got plenty of glue, probably, aye? Cut it open if ya have to...(that's the way I look at it anyway )

Matagordababy

Plenty of Glue!

I'm working on a Weight and Balance device this evening (for some reason I was a bit offput by spending $179 + shipping for the pretty commercial variety, so I invested $6.23 in a few bits which will work just as well).

I'll let you guys know how the Servo Compatibility issue plays out on Hunters Cap-232, hopefully some day this week.

Your Input is always appreciated!

Matagordababy

TedMo

With only 4.8 volts and 6 servos (digital)? you are low on voltage. Try 5 cells 6v. Only way to go with that much draw.

Steve Percifield

My Feedback: (14)

OK, still thinking out loud. I don't recall you saying the servos/system operated, just chattered. I have had this when changing receivers and forgetting to change modulation. ie: tranamitter set on PCM and using an FM receiver. Also make sure frequeny match is correct.

steve

jester_s1

His receivers are working as evidenced by the test in the Super Stick. The only thing left is the servos. There must be a compatibility issue or either a whole bad batch of them.

FlyingPilgrim

My Feedback: (26)

I get that when my antenna (either TX or RX) is not extended. Try pointing the antenna in different direction and at different distances and see if that changes.

BarracudaHockey

My Feedback: (11)

Servos are servos guys. There's a few old ones that dont talk because they are wired differently, and a few special use servos like some helicopter tail rotor servos that operate at a different pulse width but other than that, they all work the same way.

Try the JR servos, my bet would be those servos.

jester_s1

If it were my system I'd break out the digital multimeter and start checking voltage and resistance at every point that I could.

jimmyjames213

My Feedback: (2)

use a reciever/battery you know works, then start testing one servo at a time, could be a bad batt that cant handle the draw, could be bad reciever. if it seems like the servos are the problem test them on something you KNOW WORKS like a setup from another plane....if you have the same problem the servos are shot...if not get back to us.
im wondering if it could be a bad switch as well....try bypassing that

tacx

My Feedback: (1)

You say it happens to all servos except the throttle servo. Have you check the exponential settings in that particular model memory? I believe expo. settings only affect servos other than the throttle. I have seen where the exponential can be set so extremely sensitive that the servos will chatter. If it is not doing it on other models it may be because you are in a different model memory. I know you said it also does it when the TX is off, but at this point its worth checking the exponential settings.