Topic: Throttle problem ? (Read 5839 times)

Bob K · « **on:** June 10, 2012, 10:56:18 am »

A bit baffled here. I had a ‘stuck’ throttle problem at Alfold yesterday but was not able to replicate it afterwards. I always ‘pre-flight’ boats before going sailing, and again before putting them in the water. So far they have been extremely reliable. However, on this occasion after about five minutes on the water the throttle setting seemed to ‘stick’ on 2/3 forwards and would not respond to the Tx, although the rudder still worked OK.

With apologies to other boaters I managed to get it alongside and grabbed it up, props still thrashing away. Tx off, no effect. Turned off the Rx, it stopped. Took the boat back to the table, checked it out, and everything seemed to work fine. Checked out again when I got home but was unable to replicate the problem.

Any ideas?

CJ · « **Reply #1 on:** June 10, 2012, 11:06:56 am »

doesn't sound good Bob, I had that on my 27mhz and had a disagreement with the concrete bank

What setup are you running?

CJ

Tug-Kenny RIP · « **Reply #2 on:** June 10, 2012, 11:20:55 am »

As you were able to steer back to shore, we can eliminate the TX. (at least on one channel)

My thoughts are that the Speed controller had stopped acting on the Receivers signal somehow.

Hope this helps with you analysis.

ken

Bob K · « **Reply #3 on:** June 10, 2012, 11:54:35 am »

Thanks CJ and Ken. I should have said the throttle for both motors is single stick operated.
My first thought was to check the Rx servo lead connectors, but they seemed nice and tight. The twin ESC's and mixer are within a P94 unit, so my thought was it is either connection lead wiring or external interference, but interference should not just have affected throttle with rudder still working. First glitch in several months of regular use. Strange. All works perfectly now.

Tug-Kenny RIP · « **Reply #4 on:** June 10, 2012, 12:11:11 pm »

Quote from: Bob K on June 10, 2012, 11:54:35 am

Thanks CJ and Ken. I should have said the throttle for both motors is single stick operated.
My first thought was to check the Rx servo lead connectors, but they seemed nice and tight.
The twin ESC's and mixer are within a P94 unit,
so my thought was it is either connection lead wiring or external interference, but interference should not just have affected throttle with rudder still working. First glitch in several months of regular use. Strange. All works perfectly now.

There is a lot of electronics in the P494. I would ask Dave of ACTion if he has any ideas as it does sound more than a loose wire. You did quote it 'was stuck in running mode'.

ken

CJ · « **Reply #5 on:** June 10, 2012, 12:55:22 pm »

Agree with Ken, certainly seems unlikely to be a loose wire or dry joint just to get stuck....interference possibly for it to get stuck !!

CJ

Bob K · « **Reply #6 on:** June 10, 2012, 01:23:53 pm »

I am still detail checking out the system, but it remains 100% operational. It's just odd. Normally if an Rx loses signal you go into 'safe' mode and everything stops, but not only did the rudder continue to respond but it still turned on a sixpence indicating that the P94 was correctly slowing the inside prop on turns based on rudder input as usual. Pulling the stick to full reverse had no effect, it kept going 2/3 throttle forwards. I have found the P94's very reliable and much better than than twin ESC's. It is almost like the throttle input 'saw' a constant but false value from the Rx.
Maybe I should try swapping out the Planet 2.4 GHz Rx.

CJ · « **Reply #7 on:** June 10, 2012, 01:48:17 pm »

True, yeah if you have a spare one it's always worth eliminating it from your investigations

so to speak...be interested to see if you get to the bottom of it !!

CJ

DickyD · « **Reply #8 on:** June 10, 2012, 03:05:50 pm »

Is your P94 one of the original version or one of Daves new plug and play ones.

He brought out the plug and play ones because the original P94s did not always work well with the cheap 2.4 sets.

I have the original P94s which I use with Futaba r/c and the new plug and play which I use with my Planet r/c.

Just a thought.

Bob K · « **Reply #9 on:** June 10, 2012, 03:19:26 pm »

Quote from: DickyD on June 10, 2012, 03:05:50 pm

Is your P94 one of the original version or one of Daves new plug and play ones.

I have had two, fitted in different boats, both within the last six months so I guess 'plug and play'.
ie: Centre Tx sticks. Tx on. Rx on. Wait for the relays to click-click. Set up done. Impressive units.

I always test the rudder and throttle actions before lowering into the water. No problem until 5 mins of sailing.
Darned if I can make it misbehave afterwards.

john s 2 · « **Reply #10 on:** June 10, 2012, 07:57:55 pm »

I understand that Action will sell you an upgrade chip which is a simple change. Ive done this to both my p94s to enable balenced motor starting. John.

ACTion · « **Reply #11 on:** June 11, 2012, 08:21:13 am »

Quote from: Bob K on June 10, 2012, 01:23:53 pm

It is almost like the throttle input 'saw' a constant but false value from the Rx.

This sounds the most likely scenario, although quite why it should have happened is a mystery. Intermittent faults - especially those which occur just once - are the most difficult to identify. I think we can eliminate software problems or a faulty component as the unit works OK now. Electronic faults tend to happen and stay happened! While I can confidently speak for the level of QC applied to our 'British, hand-assembled from top quality components and fully tested' P94 I can't say the same for a 'Chinese, machine-soldered and assembled by outworkers' radio.
I have a Planet 5 which works fine with P94 but I only use it for testing. It may be that somehow the throttle signal from the Tx became disassociated from the stick position e.g. via a dry joint to the stick pot or some muck on the pot track which has now been dislodged. Perhaps the throttle channel moved to its failsafe position for some reason. It's all speculation, I'm afraid. Changing to a different Tx might eliminate the possibility of this glitch happening again, as I doubt if the problem is the receiver.
We will happily give Bob's P94 a once-over to check for dry joints etc and even replace the microprocessor (on the very unlikely premise that it has become unstable somehow). I don't know if it has the latest fully-Autoset software or the slightly earlier 5- or 10-second delay versions, but it can be upgraded while I have the unit.
Dave M

unbuiltnautilus · « **Reply #12 on:** June 11, 2012, 10:22:13 am »

I had a customer with a problem involving a Planet T5 and an Mtronics speed control. He said that his model would go 'throttle on' with no response from the RC gear. When I investigated this, i found that the 'last valid signal' failsafe function on the non-throttle channels on a T5 system, over ride the lost signal shut down that the Mtronics speed controls are fitted with. resulting in the throttle staying on if signal is lost. This, however, does not explain how you retained rudder control! Also, if you are using the designated throttle channel for the T5, this does not have 'last valid signal' failsafe. In fact, while I was testing three different T5s of three different dates of manufacture ( seperated by about 15 months ) , i would only rely on the latest 'green spot' R6m recievers.

oldiron · « **Reply #13 on:** June 11, 2012, 11:23:30 am »

I ran into a similar control problem with my P94 equipped Neddy this past week. Since I installed the item last year the tug worked fantastic. Last Wednesday it had a mond of its own. Go forward and it woul do so for three feet then turn left (or right). I couldn't get a reveres. As opposed to Bob's boat, mine barely made it back to shore. When on the dock t appeared to work fine. A check of all connections didn't reveal anything amiss. Running an older Futaba FM Tx/Rx.
ggeorge had just installed a P94 in his RNLI lifeboat and it ran great the same night.
I'm not necessarily pointing to the P94, but there seem to be similarities in the problems.
....or maybe it was sunspots

John

Bob K · « **Reply #14 on:** June 11, 2012, 11:29:15 am »

Many thanks: Everything still works 100% today, and I am unable to replicate that one-off glitch. It’s just weird.

Dave M: I have two P94 equipped boats in weekly use and have always found them excellent quality and very reliable. That the mixer was correctly slowing the inside props on turns strongly indicated it was not the P94, but the throttle input value it was receiving. Both are the 5 second click-click version. I will be getting another P94 soon for my latest build.

unbuiltnautilus: As Dave suggested, I am leaning towards suspecting either the RM6 Rx and/or wiring to it. It is a recent Rx, with a green spot. Changing the Rx would be worth trying, and at least I would have a spare.

John: Could well be sunspots (tee hee!) A lot of things can affect transmitted signals.

ACTion · « **Reply #15 on:** June 11, 2012, 12:51:51 pm »

Quote from: oldiron on June 11, 2012, 11:23:30 am

I'm not necessarily pointing to the P94, but there seem to be similarities in the problems.
....or maybe it was sunspots
John

John
Don't forget that P94 is just the last link in a chain from the Tx stick. If it misbehaves then the problem could lie anywhere in that chain. Like any computer it just does exactly what it's told to do, and if the signal somehow makes no sense to it then it will play silly buggers. This glitch could be the result of spurious RF interference; check the soldered joints on the suppressors to the motor cases (you have fitted them, haven't you?).

Bob
The rudder servo output pins in P94 are connected directly in parallel to the rudder input leads from the receiver, so even if the P94 does go astray the rudder servo will still respond to a valid signal from the receiver. It's no different electrically to fitting a Y-lead. If the motors were also responding to the steering signal then there is definitely a case of the throttle signal being stuck somehow. If you want us to check it over and upgrade the software then please send it back to base.

Dave M

Bob K · « **Reply #16 on:** June 11, 2012, 02:03:02 pm »

Dave M: Thank you for the offer, but I have every confidence that my P94 is doing everything it should do. I had already eliminated that from my investigations.

Captain Flack · « **Reply #17 on:** June 11, 2012, 05:27:14 pm »

My guess is that the fail safe came in

john44 · « **Reply #18 on:** June 11, 2012, 07:10:23 pm »

Dear John.

Thank you for your enquiry.

Our recent stock of Planet radios now have the original failsafe software where you can set the position of the throttle to any position. These updated receivers and the label on any set box's have a green spot label to show they are this software version.

Hope this helps

regards

Julian

Customer Service.

Hope this settles the failsafe theory. The green spot should be zero setting whatever the stick position

This E.Mail was from Perkins technical dept.

john

CJ · « **Reply #19 on:** June 14, 2012, 12:01:56 pm »

John,

After your post here it made me think to test mine - and no the failsafe didn't work (On my Fairmile).

Anyway as per my refurb (Robbe MTB) I fitted a new RX, didn't work, swapped it, wouldn't work - tried 3 new RX's in the end and either they would pair then drop out lots or not pair at all.

Anyway - long story short after a long discussion and version number checking with Perkins, they advised there was probably an issue between the RX's (green dot) and RX's (without) talking to the TX - as well as the RX's without the current version failsafe not working.

Anyway, took the whole lot back to shop and after even more testing they swapped the lot (so two on Green Dot now) and all works fine. Perkins and modelshop believe it is a faulty transmitter !!

Now reason for mentioning is whilst testing I did get the same "throttle jam" as Bob had, on a green dot version.

It may be worth checking that you too haven't got an issue Bob with a pre green dot TX having a hissy fit

with a new green dot RX !!

Anyway, it might be worth a check - and even if not would be worth checking all Planet TX/RX just in case !!

Cheers

CJ

john44 · « **Reply #20 on:** June 15, 2012, 11:02:24 am »

Hi CJ, the problem I had with the Planet Rx was that it would not work the throttle on channel 1 at all left stick useless
I had to plug the ESC into channel 3 on the Rx to get it to work, which was the right stick.
So I have fitted the Rx into my rescue boat so the throttle and rudder are both on the right stick.

john

Bob K · « **Reply #21 on:** June 15, 2012, 11:56:00 am »

Before we start blaming the electronics for an intermittent or one-off glitch, I have been determined to get to the bottom of this and have pulled out most of the electrics so I can detail test each node.

Success ! I was finally able to briefly repeat the glitch by jiggling the servo lead connectors. The fault appears to be the black wire pin on the Futaba extension lead connector. For a moment the props revved to full speed with the stick at neutral.

I guess if that channel’s circuit cannot ‘see’ both halves of the circuit then it may be getting its return elsewhere and generating an erroneous function. I have replaced the servo lead and cannot generate the glitch so hopefully we are good to go.

The moral is if you have a spurious fault always suspect wiring and connections first.

john44 · « **Reply #22 on:** June 15, 2012, 06:20:47 pm »

Hi Bob, what happens if you turn off the transmitter ( lost signal ) nothing should happen, if it goes flat out
it is the modified Rx version, with a black spot with the full on failsafe.

john

Bob K · « **Reply #23 on:** June 15, 2012, 08:10:42 pm »

Hi John. As stated before, I have the latest Rx. There was no apparent of signal as the rudder still worked fine, so 'fail safe' did not apply.

However, with Tx then Rx switched on (sticks centred), jiggling that black servo connector lead wire caused the props to run continuously, not responding to the stick. The throttle sticks on. Spurious feedback loop due to loss of -VE on that channel.

I replaced the servo extention lead with a new one. Problem solved.

malcolmfrary · « **Reply #24 on:** June 15, 2012, 08:43:32 pm »

Glad to see you nailed it, Bob.
As a wise old man once told me when he was trying to teach me how to fix electric stuff, "Get as technical as you like, but look for broken wires first." A faulty ground line can give all sorts of spurious faults in an RC setup, especially one where there are possible alternative paths.

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Author Topic: Throttle problem ? (Read 5839 times)

ACTion

ACTion