problem with reverse module servo

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C

comicaltone

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5
Hi,

I've recently installed the reverse module on my savage x, I have the 2 channel version with mixer. the reverse works fine with the throttle but when i steer the servo pulls the reverse module into reverse. I've double checked the wires and everything is ok. I'm using a JR sport st47 standard servo. Please can anyone help me.

My first post

Comicaltone
 
It shifts into reverse after holding the break on for 3 secs?
What exactly happens when you steer? Does it only happen in one direction or both? Does it shift back to forward when steering at all?
 
Hi,

I am pretty new to this but I have installed the reverse module. Maybe I can help.

To me it sounds like either you have the mixer pluged into the steering output on the rx (the wrong channel), or (and maybe more likely from what youve said) maybe you have the horn (I think it is called a horn, the part that screws onto the servo that the linkage attaches to) on in the opposite way (pointing towards the steering servo, so when you trun in one direction the horn on the steering servo is hitting the horn on the reverse servo.

Really like Keithv said, more info is needed. maybe a pic of the underside of the truck, of the steering and reverse servo setup.

Also, this isn't probably your problem but might be part of it, make sure the assembly with the silicon rubber peices and 2 brass peices is the correct length, i think it should be 26mm, it shows in the instructions and the picture in the instructions is actual size, so you can set your linkage on top of the picture and make sure it is the same.

I hope that helps,

John
 
Wister said:
Hi,

I am pretty new to this but I have installed the reverse module. Maybe I can help.

To me it sounds like either you have the mixer pluged into the steering output on the rx (the wrong channel), or (and maybe more likely from what youve said) maybe you have the horn (I think it is called a horn, the part that screws onto the servo that the linkage attaches to) on in the opposite way (pointing towards the steering servo, so when you trun in one direction the horn on the steering servo is hitting the horn on the reverse servo.

Really like Keithv said, more info is needed. maybe a pic of the underside of the truck, of the steering and reverse servo setup.

Also, this isn't probably your problem but might be part of it, make sure the assembly with the silicon rubber peices and 2 brass peices is the correct length, i think it should be 26mm, it shows in the instructions and the picture in the instructions is actual size, so you can set your linkage on top of the picture and make sure it is the same.

I hope that helps,

John
Click to expand...

Nice call wister. don't know if thats the problem but sure sounds like it could be. See you can be of some help even though you are a newbie.
 
hi, ok will get pics asap. it only goes from forward to reverse never the other way round. i have taken the radio gear out and have had it on my table for a day now just trying to find out what is causing it.

I definatley have them plugged into the correct sockets. It works as its supposed with the throttle i.e hole brake for 3 seconds and it will go into reverse or vice versa. But it also seems to go from forward to reverse when i'm steering not instantly it may take 10 seconds and i've checked to see if the steering mecanism is touchng the servo but it isn't. If the mixer is not connected to the steering servo in anyway all i can think is that i have a problem with the reciever as their is no conection what so ever with steering and mixer.
 
I don't think it would be the mixer. Sounds like it could be a bad RX though. What kind of radio are you using? Can you get another RX to test it out?
 
Hi,

Yes, if everything is connected correctly for sure. then most likely it could be either your TX or RX. The radio sends a seria PPM signal (I am not really fimular with AM radios, but I am pretty sure they use PPM) all of the data is in one stream so it sends pulses of different lengths, inside the RX it gets decoded (actually de multiplexed with a counter) to the 2 channels (in the case of a 2 channel rx) so either 2 things could be happening. either the radio is sending a bad signal that is getting decoded incorrectly, or the rx is getting the correct signal but either receiving it wrong or decoding it incorrectly.

There is always a chance the mixer is bad too, but to me It seems like because it happens when the steering is moved that some of the data for the steering is getting demuxed into the throttle channel, actually it may not even be noticed without the mixer in the circut, it would probably just cause the brake to activate or chatter.

I would try the RX firt then the tx. of course it is easier to try the TX if you have another one to try it with.

If you want to see how the demultiplxer/decoder works google a "4017 decade counter", one signal goes in the clock and from 1 to 10 signals come out. Each output could be a channel.

Still doesn't help much, it boils down to trying each part.

John
 
Wister said:
Hi,

Yes, if everything is connected correctly for sure. then most likely it could be either your TX or RX. The radio sends a seria PPM signal (I am not really fimular with AM radios, but I am pretty sure they use PPM) all of the data is in one stream so it sends pulses of different lengths, inside the RX it gets decoded (actually de multiplexed with a counter) to the 2 channels (in the case of a 2 channel rx) so either 2 things could be happening. either the radio is sending a bad signal that is getting decoded incorrectly, or the rx is getting the correct signal but either receiving it wrong or decoding it incorrectly.

There is always a chance the mixer is bad too, but to me It seems like because it happens when the steering is moved that some of the data for the steering is getting demuxed into the throttle channel, actually it may not even be noticed without the mixer in the circut, it would probably just cause the brake to activate or chatter.

I would try the RX firt then the tx. of course it is easier to try the TX if you have another one to try it with.

If you want to see how the demultiplxer/decoder works google a "4017 decade counter", one signal goes in the clock and from 1 to 10 signals come out. Each output could be a channel.

Still doesn't help much, it boils down to trying each part.

John
Click to expand...

WOW ALOT OF GOOD INFO THERE!!!! :10:
 
I think i've done this right but i've attached a video as a ZIP file. in this vid you can see what happens, Just so you know i'm not touching the throttle at all only the steering.I'm just using the atock radio that came with my savage x 4.6RTR
 
DO you have access to another servo or a different receiver? I'm leaning more towards a receiver problem with it "leaking" the signal to that channel. Have you tried swapping that servo with the throttle servo? don't drive the truck, just test it the way you did in the video and see if it still does it.
 
yes. i swapped the servos over and tried throttle one and the same happens. just trying to arrange to use a friends radio to see if its that but i'm with you on thinking its the reciever
 
I think its a receiver problem too. Let us know how you make out when you test the other one.
 
I would think it wouldnt be the mixer, from my understanding. I don't have a mixer, so this is all my guess... I just use a 3 channel outright, but the linkage that moved the reverse lever kept jumping off the lever so I just disengaged it all together until I rebuild the tranny/reverse mod, as I broke the lever trying to bend it, stupid metal "fiberboard" as I call it, but I digress.

But it sounds to me that the mixer would plug into only one connection, so if it works with the throttle signal, it would have to be the RX leaking signal. I doubt the transmitter would send throttle signals of full brake and have that be picked up on by the mixer, while the truck is still getting gas. Actually I don't see how that could happen even with a faulty RX. Hopefully someone understand what I'm saying... =P

Try this (with the motor off, obviously): Apply full throttle, and use the steering. First try this without the mixer, and if your throttle goes haywire, its definitely your RX/TX. If, with the mixer, the mixer shifts and the throttle is fluky, when without the mixer everything was fine, its your mixer. If the truck stays WOT, and the mixer shifts, I don't know what to tell you, it would most likely be the mixer in that case as it could be "thinking" it is getting brake.

Another obvious thing to check, though since you said it works with brake/throttle so this would be a sidenote to consider, is servo reversing. I don't know how the mixer picks up on direction, because again, I don't have one.

I'd say scrap it and get a Futaba 3 channel, but that's just because I don't like these perplexing headaches 😉
 
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