Go Back  R/C Tech Forums > General Forums > Radio and Electronics
Futaba 4PLS frozen throttle channel >

Futaba 4PLS frozen throttle channel

Like Tree5Likes
  • 1 Post By Vedat560
  • 1 Post By Roelof
  • 1 Post By 1/8 IC Fan
  • 1 Post By belewis01
  • 1 Post By Vedat560

Futaba 4PLS frozen throttle channel

Reply

Old 08-07-2019, 05:52 AM
  #1  
Tech Rookie
Thread Starter
 
Join Date: Jul 2019
Posts: 5
Default Futaba 4PLS frozen throttle channel

Hello everyone,

I am an R/C car modeller for more than 20 years, but was away from the hobby for the past 10 yrs. I recently bought a brand new 1/5 gas car and a second hand Futaba 4PLS radio, close to brand new condition.

It was perfectly OK during hand-over check, and also during installation to my car.

On my first field visit, I set subtrims and all on a parking lot, and then went on to the track. I ran the car about 5 minutes at a moderate pace, but suddenly the car jerked forward and ran into the fence until I got to it and killed the engine manually.

I thought it would be because of the receiver battery (I had not set failsafe then), so next week I went to the track, but this time with a dead throttle with no response at all. Next weekend I went to my friend who is the manufacturer of the car, to help me with the radio, but the radio worked perfectly well there. Naturally my friend came to the conclusion that I accidentally reduced throttle and brake servo end points to zero, showing me like a rookie.

So next week I again went to the track, started the car, checked throttle and brake, put the body on with engine idling, and while I reached for the radio, the car suddenly jerked and ran into the pit fences at close to full throttle. I again killed the engine manually and the radio since then shows a frozen throttle channel at ¾ throttle. Throttle/brake trigger produces no response. With the engine not running, I turn on the car which goes into ¾ throttle instantly and stays there. I shut off the transmitter and the throttle goes into full brake normally because of failsafe, but as soon as I switch the transmitter on, again ¾ throttle instantly.

Even days after, the radio display shows a frozen ¾ throttle whenever it is switched on (photo attached). One may naturally suspect the trigger potentiometer, but it wouldn’t explain jerking to throttle by itself.

To top it all, the transmitter decided to work perfectly on the 11th day, and it still does.

I wrote this to Futaba and the answer I got from them is

QTE

Regarding the 4PLS,
Please check the EPA setting.
The initial setting of FWD and BRK are 100% each.

We guess that the value of the 4PLS is 0%.

UNQTE

I was really startled and dissapointed to receive such a reply from Futaba. Obviously they have not read my mail message thouroughly, and just shook me off! “Come on Futaba guys! You should do better than that! How would a 0% EPA setting explain a frozen throttle channel at ¾ fixed throttle for the last 10 days, let alone a perfectly running radio today!”

I’m 100% sure the radio is shot, but having received such an answer from Futaba brings me to a dead end street. Any ideas will be appreciated...

mushroomed likes this.
Vedat560 is offline  
Reply With Quote
Old 08-07-2019, 07:41 AM
  #2  
Tech Champion
 
Roelof's Avatar
 
Join Date: Aug 2007
Location: Holland
Posts: 8,012
Default

Did you try a model reset?
1/8 IC Fan likes this.
Roelof is offline  
Reply With Quote
Old 08-07-2019, 07:59 AM
  #3  
Tech Elite
iTrader: (91)
 
1/8 IC Fan's Avatar
 
Join Date: Jan 2012
Location: North America & Europe
Posts: 4,907
Trader Rating: 91 (100%+)
Default

Reset the Radio as Roelof stated, or change you EPA!
1/8 IC Fan is offline  
Reply With Quote
Old 08-07-2019, 08:02 AM
  #4  
Tech Rookie
Thread Starter
 
Join Date: Jul 2019
Posts: 5
Default

Originally Posted by Roelof View Post
Did you try a model reset?
many times...
Vedat560 is offline  
Reply With Quote
Old 08-07-2019, 08:03 AM
  #5  
Tech Rookie
Thread Starter
 
Join Date: Jul 2019
Posts: 5
Default

Originally Posted by 1/8 IC Fan View Post
Reset the Radio as Roelof stated, or change you EPA!
An EPA setting would not explain a sudden throttle and staying fixed there, would it?
Vedat560 is offline  
Reply With Quote
Old 08-07-2019, 10:17 AM
  #6  
Tech Master
 
the rc guy's Avatar
 
Join Date: Aug 2016
Location: Detroit
Posts: 1,482
Default

intermittent radio problems are always a hassle..do bench tests without a running engine.. maybe get a cheap radio that you know that works.install a non receiver failsafe . there are a few people like a certain brand I dont run gas so no knowledge of those.. futaba is like you said..bad cs at best.
the rc guy is offline  
Reply With Quote
Old 08-07-2019, 12:22 PM
  #7  
Tech Regular
iTrader: (6)
 
Join Date: Nov 2011
Posts: 288
Trader Rating: 6 (100%+)
Default

Originally Posted by Vedat560 View Post
An EPA setting would not explain a sudden throttle and staying fixed there, would it?
Why not try this since Futaba and others are suggesting it? It is a process of elimination, and has to be easier than running your car into the fence again... it may be that a zero value in any setting would cause unusual behaviour but the intermittent problems you are having make it less likely that that is the case.

Reset the radio as there are multiple models settings. This will limit the possibility of having two different models settings and switching between them and causing problems.

Check the movement of the throttle servo with the engine off to make sure it isn't forcing the linkage or straining the servo. Check the throttle EPAs as well as FWD and BRK as previously suggested.

Because of what you mention of the throttle stuck showing as 70%, it could be a problem with the potentiometer of the throttle. If you are confident to do it, you could try opening the radio and spraying the potentiometer with electrical contact cleaner.

Also, it is possible to recalibrate the throttle using a function in the menu that is called 'Adjuster'. This will reset the centre point for each channel and is not effected by doing a factory reset. Instructions from the manual attached.




mushroomed is offline  
Reply With Quote
Old 08-07-2019, 01:13 PM
  #8  
Tech Elite
iTrader: (91)
 
1/8 IC Fan's Avatar
 
Join Date: Jan 2012
Location: North America & Europe
Posts: 4,907
Trader Rating: 91 (100%+)
Default

Originally Posted by Vedat560 View Post
An EPA setting would not explain a sudden throttle and staying fixed there, would it?
if you calibrated your ESC at 100% EPA for throttle, then inadvertantly misadjusted the radio to 0 EPA, then technically yes! Depends on what 0 EPA corelates to your ESC. Roelof may be able to explain better. Yet try resetting your radio and calibrating your ESC. I have run the 4PL and 4PLS since they came out with no issues.
mushroomed likes this.
1/8 IC Fan is offline  
Reply With Quote
Old 08-07-2019, 09:44 PM
  #9  
Tech Addict
iTrader: (4)
 
Join Date: Dec 2015
Location: San Jose CA
Posts: 593
Trader Rating: 4 (100%+)
Default

Originally Posted by Vedat560 View Post
Hello everyone,

I am an R/C car modeller for more than 20 years, but was away from the hobby for the past 10 yrs. I recently bought a brand new 1/5 gas car and a second hand Futaba 4PLS radio, close to brand new condition.
Originally Posted by 1/8 IC Fan View Post
if you calibrated your ESC at 100% EPA for throttle, then inadvertantly misadjusted the radio to 0 EPA, then technically yes! Depends on what 0 EPA corelates to your ESC. Roelof may be able to explain better. Yet try resetting your radio and calibrating your ESC. I have run the 4PL and 4PLS since they came out with no issues.
No ESCs in a 1/5th scale gas car
Vedat560 likes this.
belewis01 is offline  
Reply With Quote
Old 08-08-2019, 12:11 AM
  #10  
Tech Rookie
Thread Starter
 
Join Date: Jul 2019
Posts: 5
Default

Thank you all for your concern and inputs; especially "the rc guy" and "mushroomed"

Of course I have tried everything including EPA, multiple model resets, adjuster menu, and mechanical throttle/brake components with no success. As I wrote, the radio is presently functioning with no issues at all, and this is what makes the problem very hard to detect.

It was also because of this that I eliminated the potentiometer issue in the first place, however come to think of it, there is a faint chance that it may be the source of the problem for two reasons;
One: An electrical contact/short issue does not necessarily have to be consistent; it can be intermittent especially at the initial stages of the malfunction,
Two: It does sensibly match with the problems I have been facing which were a non responsive throttle, and an unexpected throttle input.

So my last resort will be to open up the radio and check/clean/replace the throttle potentiometer. If that does not work, and if Futaba responds me with a service facility in Europe, I will send it there. If not, the radio will R.I.P. in the electronic garbage box, because it will cost more than a new radio to send it back and forth to Japan from Turkey.

Thank you all once more for your inputs helped me open up my mind for the potentiometer issue.

I will post the outcome for those who may want to know..

Thanks
mushroomed likes this.
Vedat560 is offline  
Reply With Quote
Old 08-08-2019, 05:24 AM
  #11  
R/C Tech Elite Member
iTrader: (205)
 
Marcos.J's Avatar
 
Join Date: Sep 2003
Location: Semper Fi
Posts: 30,191
Trader Rating: 205 (100%+)
Default

if your throttle is frozen just "Let it Go"
Marcos.J is offline  
Reply With Quote
Old 08-08-2019, 06:48 PM
  #12  
Tech Initiate
 
Join Date: Aug 2018
Posts: 27
Default

The throttle pot on my 4pls went bad, it resulted in jittery throttle application. I found a cheap radio, and swapped the pots, solved the issue. Problem is, its hard to find the right replacement. Best of luck to you.
AndyArdmore is offline  
Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service