Pree

Hi guys, Im having a problem with my new Futaba 4pks. Everything works fine except every now and then the throttle servo will not respond.... The steering works fine only the throttle. There is power going to it but it is left in neutral. The fail safe I have set is with the brakes on, so I don't think the fail safe is engaging. Have I got a setting wrong? Thanks for the help in advance..

Throttle Servo is Hitec high speed titanium

Steering Servo is JR metal gear normal speed

Both are digital

jmaxey51

iTrader: (7)

your servo may be fried. try switching the throttle with steering and see if it works then, if the throttle works when you plug it into the steering then something is going wrong in the receiver, if not then you'll know its the servo not radio.

Dyno-Dylan

iTrader: (36)

Im having the same issue with my car. Hopefully someone can shed some light on this. What receiver and receiver pack are you using?

strngdze

iTrader: (16)

Pree/Dylan,

Which car are you both having these issues in? Also, are you running lipo direct or regulated?

Dyno-Dylan

iTrader: (36)

I am running losi cars. I have two buggies with the same issue. Also using protek LiFe packs. I emailed futaba and they said it sounds like the receiver is going into failsafe. I checked my radio and the failsafes were turned off so how can that be?

Pree

Im using a Losi 8ight 2.0, with a 1900mah receiver battery fully charged. The Servo for throttle is relatively new - Hitec HS-5985mg and the steering is - JR ES-579. The RX on the transmitter is set to normal not high response. Weird as I never had this problem with the Spektrum Dx3r Pro with the same servos....

stevehof

Have you tried anything to fix it yet?

I have had weird uncommanded responses from two of my cars. One on a 4PKS and the other on a 4PL. I fixed the 4PKS issue by rerouting the wires and putting the antenna up in a vertical whip. I just fixed the 4PL issue yesterday with a Novak 'glitch buster' capacitor. Evidently, the Mamba Monster Pro BEC can't deal with a high speed high torque servo on a 2s setup. Even though you are using a receiver pack, it might be interesting to see if the addition of a capacitor might fix your throttle servo issue.

Dyno-Dylan

iTrader: (36)

Its funny you mention the capacitor as my Dad suggested trying it. Ive been testing everything at my house and it all works fine now. However, it worked fine in the pits last week but as soon as I turned a few laps it started up again. Ill be racing saturday so that will be the real test. Ill be bringing my trusty 3pk in case it acts up again. Futaba's answer is just to send it in. Glad I have something that cost $500 to have to send it in for repair.
I'm assuming your cars are electric? Also which receiver are you using with your 4PL radio? Also what about the 4PK receiver?

Dyno-Dylan

iTrader: (36)

Pree- I apologize for somewhat hijacking your thread. However hopefully with two of us on here we can figure out the issues sooner.

Dylan

stevehof

Yes, both cars are electric. The 4PKS is using R614FF & Tekin RX 8 ESC and the 4PL is using a R2104GF & Mamba Max Pro ESC. I Probably should just put a 10 amp BEC on the Mamba Max system but the capacitor totally fixed the stop & go with turn in behavior. It was just like it lost all power to everything. The funny part of all this is that the car did this behavior at the exact same spot on the track on nearly every lap. It was like the first thing to go when the receiver lacked enough power was the ability of the receiver to process the signal when it was located on a vulnerable spot on the track. My second choice guess would be that the power got so low the receiver was resetting. After a couple of seconds it would truck on like nothing was wrong.

Dyno-Dylan

iTrader: (36)

Interesting, it seems the one thing in common with all of us having an issue is the r614ff receiver. Ive read guys say they are using the 603 receiver without a problem.

strngdze

iTrader: (16)

The reason I asked which car, was that I had the exact same issue in my DNX408. Futaba 4PKS, 614 receiver, direct lipo to Hitec 7955 servos (Throttle/Brake).

This turned out to be an issue with the layout of the car. The engine is approximately 1/8" away from the bottom of the servo right where the electronics are. I initially thought they were failing intermittently (cutting out) due to vibration. I went through 3 servos before I really figured out the problem. I was esentially cooking my servos from being so close to the engine case. Fortunately they were Hitec servos and their warranty program is rock solid.

I was able to solve the problem by using heat shield tape on the bottom of the servo's.

stevehof

Is the 603 the receiver that came with the original 4PK? 2 years ago I had a 4PK and 3 receivers and never had any weirdness. I personally think the 614 might have some issues with reception on a crowded track. However, since I got the steering servo wire bundle out of the receiver box and set up a vertical antenna, I've had smooth sailing for a dozen packs or so with that truck.

Dyno-Dylan

iTrader: (36)

I believe the 603 is what came with the original 4pk. The 4pks comes with the 614 receiver and Im wondering if that is where the issue comes up

DeLaSoul

Not sure if this is exactly the same as you have experienced but I have had a similar issue for quite some time which I have only just managed to resolve.

Scenario: I run the 4PK-S with the 614 rx in gas & electric. I kept losing the throttle but only at the track and then only when certain other transmitters were around. I tried new servos, recievers, LiFe rx packs/speed controllers but nothing cured it so we assumed it was a form of interference from the other transmitters which in theory can't happen (or so I am told by Futaba). I have even had my handset checked on a spectrum analyser and the signal was strong and clean. I pulled the servos apart and checked them, put a DVM across the RX and loaded the servos and measured the drop. Nothing showed up as out of place. All pointed back to other peoples kit.

Cure: So far I have done 5 meetings and no issue. I switched the handset from "BLS" servo mode to "Normal" in the RX SYS menu. No issues at all since - so I would say have a look on the menu and switch mode. I have no real understanding why this would work - I have been running Futaba BLS servos and it didn't seem to like it!!

HTH