Hi Guys

I don't have a servo tester but I noticed this and pulled the Futuba 9202 servo.

My Turbine Mavrick has Futuba 9202 on it's ailerons. when I would move the stick back and forth for a flight control check one servo noticeably was lagging. It then seemed to bounce back to a neutral position.

Over the next few days I tested it and it led to a full down position and locked there.

I ordered a new one. In trying to figure what happened I hook it up to a spare PPM receiver it seems jittery but functions OK anyone have any thoughts what might have happened to it?

Ian

Ian

Not worth taking a chance, replace it.


Just a thought............ Johnny Hernandez

Ian
had a similar problem with JR 4721, changed servo and problem was still there.Solution was to replace WYE cable ...problem was corrected
semper Fi
Joe

Ian, its a bad feedback pot....replace the servo like J says.

Dave

9202 is $50-60 right?
turbine maverick about $4500-6000
Crash Video priceless.

i think bad feed back pot too Solution buy a new servo.

Ian,

I had a similar problem with Futaba 9202 servos that I had in a CJM F-104. The problem only seemed to occur with a fully charged 4 cell battery pack. The servos seemed to jitter less as the voltage of the battery pack dropped. At 5.2 volts the jittering stopped and the servos were rock solid. I switched from a ppm receiver to a pcm receiver and it eliminated the problem completely.

Paul

I've seen Y cables and servo extensions do that. They look perfectly fine on the outside, but after they were replaced, the problem disappeared. I've also had a lessor F aileron servo lock full up. This was in a flying boat...I knew the servo was iffy, but thought I had resolved the problem.....not! It spun in.

A couple of things you can try is to try a different servo in that position, and see if the problem persists or goes away. Similarly, try that problem servo in a differnt location as see the result. I would really have problems trusting that servo in a jet, though.....

PPM is the first problem.

4.8v may pack is the second.

Long runs may be the third.

The Y may be the fourth.

For best results use a PCM reciever, a 6v pack with a 5.1v regurlator and run the aeil on seperate channels.

I have been doing this for about twenty years, and have never had a problem flying giant scale, pattern, helicopters and both DF and turbine jets.

Short cuts and unneeded complex systems are often times a receipt for failure.


KISS

On my F100 Ive noticed that one of my flaps can be pushed slightly easier than the other. Still plenty of tention but the servo doesnt seem as strong as the other. Could this be the Y harness or the servo? The servos are 2721. What do you think?
Scott

IAN,



Buy a New Servo

Guys

I bought the new SERVO before I even wrote this from tower however I found out an interesting thing when testing the system.

Seems part of the problem is the 6 inch servo extension it must have a bad lead in it. When this is out of the system it works fine. However being the anal PILOT type the S 9202 that was in there will be used as parts only.

Diceman U know I don't fly anything other the PCM I just had a PPM and ur old 1800mah battery sitting around for a second opinion.

Also I really need to get that 500 stand from you this week J.B.

Presta sorry I missed ur flying at FJ 05 I heard u were ripping better then last year.

Johnny H thanks dude whats the story with BLUE PM me.

Thanks ALL I appreciate the great resource of information you guys provide when I am in the Sand Pit I will be counting on your help.

Ian

I don't exactly have a jet, although i will not to far away but i had a servo failure of a brand new JR servo in my WM Dago Red p51 on its maiden and it scared the crap outa me thinkin i'd lost a brand new plane, engine and gear... luckily it landed perfectly as the elevator servo that failed failed with about 5% up elevator! Replaced that with another brand newy, and some how freakishly the same elevator servo stripped all four mount bolts and the servo was floating... miraculously it landed fine again... so two flights in a row, two '1-in-a-thousand' incidents on the same servo on the first two flights... it aint a good feeling thats all i know... if it was a Jet, i'd be crying for weeks at even the thought of failure

If you want to believe OEM hype on their products, I found some shred of truth in JR claims to not use anything but their brand of extensions, y, switches, whatever because of the plug pin and socket engagements being so varied that the contact surface of varying designs are not as required by design.

I make all my wire extensions and use an aftermarket part of gold. Because these pins contact each other on both sides of pin considered by OEM as "high insertion force" I replace plugs on servo side as well.

If you carefully examine pin engagements of OEM to OEM make sure your aftermarket stuff is identical, I have found there is very few that are identical engagement and dimensions of pins as using like OEM parts. FWIW.........

C/f, you are right on the money here! In fact on some larger gassers with long runs I limit the number of plug connections. Soldering when you can sure helps servo performance!