Problem with rc unit

[rkkm]

Hi

My rc unit is doing some clicking sound when steering to left, and i think that it is not perfectly returned to center, pin hole is always set a bit to left or to right, any solution? My normal pf servo never had that like problems...

[mocbuild101]

Sounds like one of the gears inside it has slipped - you will need to take it apart and have a look , but make sure you don't strip the screws when you open it!

You could also try to realign the gears by turning the steering output by hand, but this might break some of the gear's teeth.

Post some photos (or video) of it before you open it, so I can see the problem.

Edited May 25, 2017 by mocbuild101

[rkkm]

dunno where to post video, do u got facebook or u know how can i  post here vid?

[Alex Ilea]

Use YouTube for videos .

[mocbuild101]

43 minutes ago, rkkm said:

dunno where to post video, do u got facebook or u know how can i  post here vid?

You can use Bricksafe for pictures, and if you are not on YouTube you can also use it for videos, just by linking them (the pictures will be automatically embedded, but the videos can only viewed by downloading)

[rkkm]

i will post photos of servo, cause i have demonted it, and i see that clicking sounds are not worth minding them, but really servo is never centered, always bit left or right and i see it better from inside

[Marxpek]

mine also has about a millimeter of play left to right, that's just the wear on the gears i guess, but when used with the rc-front, which is loaded with springs to help to return to center, the problem isn't nearly as big.

1 hour ago, mocbuild101 said:

Sounds like one of the gears inside it has slipped

If i recall it right this cannot occur, the circular output gear has position recognition, which means that the gear on the servomotor, which drives it, will just keep turning when it senses a wrong position compared to the transmitters input (this causes the clicking sound when you stall the steering output on the rc unit, grinding gears). not 100% sure, but i think it works like that.

[mocbuild101]

1 hour ago, Marxpek said:

If i recall it right this cannot occur, the circular output gear has position recognition, which means that the gear on the servomotor, which drives it, will just keep turning when it senses a wrong position compared to the transmitters input (this causes the clicking sound when you stall the steering output on the rc unit, grinding gears). not 100% sure, but i think it works like that.

If you are right, it could mean that the contacts of position sensor are dirty - because that would mean that the RC unit doesn't know when to stop turning the motor. (but the output would stop because it has been blocked)

By the way @rkkm, didn't you say that you drove it in/near sand?

[Marxpek]

3 hours ago, mocbuild101 said:

it could mean that the contacts of position sensor are dirty

Good thinking! worth checking for sure!

[rkkm]

On 25.05.2017 at 3:10 PM, mocbuild101 said:

If you are right, it could mean that the contacts of position sensor are dirty - because that would mean that the RC unit doesn't know when to stop turning the motor. (but the output would stop because it has been blocked)

By the way @rkkm, didn't you say that you drove it in/near sand?

Yes you are right, but engines started to not work good imadiately, rc unit servo started doing it about week ago, ill try clearing it.

but it wasnt in sand, it was near playground, and there was a bit sand on path

[rkkm]

sensors are clear but there is problm with them. ill uload vid in few minutes.

[rkkm]

Photos of sensors here:

https://www.flickr.com/photos/154883928@N06/?

Vid of sensor work, remember to turn on music to hear motor:

 

https://vid.me/aBwB

On 25.05.2017 at 3:10 PM, mocbuild101 said:

If you are right, it could mean that the contacts of position sensor are dirty - because that would mean that the RC unit doesn't know when to stop turning the motor. (but the output would stop because it has been blocked)

By the way @rkkm, didn't you say that you drove it in/near sand?

so what do u think?

[Marxpek]

Checked the pictures and the video to me everything seems ok at first glance, motor starts to turn when you take it out of the center and contacts seems decent.

Do you have a video of the exact problem that occurs? or what you are trying to fix? 

38 minutes ago, rkkm said:

sensors are clear but there is problm with them. ill uload vid in few minutes.

What is this problem? the video does not show it.

 

[rkkm]

if u watch carefully, u will see that when i turn this thingy with sensors, motor dont work imadiately, there is a bit space in left and right where sensors dont work, and servo is uncentred

ill try making better vid

[Marxpek]

Is the servo always uncentered to the same direction? 

48 minutes ago, rkkm said:

there is a bit space in left and right where sensors dont work

Please consider that you are testing this without the housing, breaking the position sensor connection is easily done like this.

how much space/play are we taking about here? is the play more then 1/16th of a full rotation both ways? 

Again: if i recall it correct (and until now i have ;D) the steering should have 7 positions: far left, middle left, light left, center, light right, middle right, and far right. (if you look at the top of the electrical board you can see the 7 positions for the contacts)

if the unit is assembled, can you get the servo into these 7 positions? if that is the case, your contacts are fine (which is what i'm guessing here) If you cannot get the 7 positions, there might be something with the sensor connections, might be worth trying to slightly bend up the drag-connectors on the steering output gear for better connector, but be careful...

[rkkm]

Just now, Marxpek said:

Is the servo always uncentered to the same direction? 

Please consider that you are testing this without the housing, breaking the position sensor connection is easily done like this.

how much space/play are we taking about here? is the play more then 1/16th of a full rotation both ways? 

Again: if i recall it correct (and until now i have ;D) the steering should have 7 positions: far left, middle left, light left, center, light right, middle right, and far right. (if you look at the top of the electrical board you can see the 7 positions for the contacts)

if the unit is assembled, can you get the servo into these 7 positions? if that is the case, your contacts are fine (which is what i'm guessing here) If you cannot get the 7 positions, there might be something with the sensor connections, might be worth trying to slightly bend up the drag-connectors on the steering output gear for better connector, but be careful...

Servo is always uncentred, if i steer to left - servo goes to much to right when going back centre, and also when i steer right same thing happens but into left, dont know what u mean about space/play. yeah i got 7 positions as u said.

[Marxpek]

Just now, rkkm said:

dont know what u mean about space/play

How much degrees can you turn the servo output without grinding the gears and without using any force? 

In other words, how much can the servo output freely move? (play/room in the system, because of old/worn internal gears)

or: put and axle in the servo output, how much can you turn it by hand? (do not use any force)

[rkkm]

it turns 45 degree normal, but using no force isnt rotating, new vid with me talking and un good quality is uploading, wait few minutes

[Marxpek]

6 minutes ago, rkkm said:

but using no force isnt rotating

That is great! that means your internal gears are in good shape, and since you can get the 7 positions in steering as well, i really do not see what can be a problem here at the moment, sounds as if everything works fine, is the steering failing in a tested car with a good setup?

But i'll waiting for that video, maybe i'll get new idea's..

Edited May 26, 2017 by Marxpek

[rkkm]

here it is, dont laugh loud when u hear my english :) hope this vid will show where the problem is

https://vid.me/I64e

[Marxpek]

Your English is perfectly understandable no problem!

And i see what you mean now, the output gear has 4 little metal pegs, lets call these the "drag-contact"

This drag-contact does it have some corrosion? (rusty, dirty or worn) you could try to clean em with alcohol and polish them a bit.

The drag contact connects several metal tabs (the "7 positions" for example) on the electrical board, is any of these tabs damaged worn or dirty?, try cleaning them with alcohol and a cue-tip first, maybe even lightly polish them, but be careful it's thin metal.

 

On this picture of yours i cannot see if the lines inside the tabs are damage or just light scratch marks, also dirt or grease between tabs could cause it to make false connections,

so check all connecting elements (drag-contact and electrical boards metal tabs) for damage / (deep) scratches, maybe polish, and then clean with alcohol.

Also very light bending the drag-contacts might help making better contact with the metal tabs, if 1 connection is not touching somewhere properly, steering is off, probably your issue.

 

 

 

[rkkm]

Ok heres new photos, https://www.flickr.com/photos/154883928@N06/?

 

[mocbuild101]

By what the two videos show, it is working exactly how it should!

Although it does sound like the motor itself is dirty (inside the motor's metal case).

I had the same problem with my Lego Dirt Crusher RC, and I fixed it by taking the motor apart and cleaning it (along with everything else).

After listening to the video again, it actually sounds fine. You will never get it perfectly centered.   

Edited May 27, 2017 by mocbuild101

[mocbuild101]

Here is a video of my working RC unit's steering output while I am moving the control stick by varying amounts: http://bricksafe.com/files/mocbuild101/mocbuild101/RC Unit Demo.AVI

You have to download it to view it, but you shouldn't have any problems because it's in the standard AVI format.

Hope that helps .

[rkkm]

give me a while, i post another vid cause i think u wont see problem inside as i see, i do same video as u, your rc unit is centred perfectly.

here you go: https://vid.me/SV5j

compare mine to yours and u will see my problem