Big Rock Arrma Big Rock 3S servo failure>>> servo change and red blinking light

[m71295]

Hi everyone ...looking for advice here. We were driving and the rc had lost control on a left turn, we thought it was the servo and therefore we replaced it with the Savox 1210SG. Towards the end of the replacement the rc started to hit the throttle by itself which made no sense as no one was touching the throttle. When we screwed in the final bits we tested it and the red light started blinking on the esc, we changed our battery but it still was blinking, any advice on what it could be? Could we have damaged the esc while handling? Could it be maybe that we messed up the connection in the box ? I'm having suspicions that the stock may be okay. I tried to improvise with the servo saver since the new servo is 25T and I had a successful attempt (I drilled the original servo saver to get the cap off and replaced the cap with a 25T cap) but now I'm regretting it since the original saver is already ruined.
Does someone know what may be the issue ? Newbies here but I do understand technology so I can understand what may have happened. I just need your experience and advise guys!

UPDATE: Blinking light was from the remote. The throttle wasn`t set up in the middle. Looking for new servo saver now.

 

[Kusher]

Did you retry calibrating the ESC? And as for the servo I have an aftermarket one and use the Traxxas slash horn for it no servo saver. Or you could get the arrma 25t servo saver.
with aftermarket servo the original saver did not work was too long but with the slash one it works perfect. Mine went out on my bigrock 3 days after I got it.

 

[sylentknyte]

First thing I’d do is check transmitter is still bound. Then I’d reset the esc. Then set the end points for the servo and throttle.
Manual should tell you how to do it on the Big Rock. Person doubt the esc is faulty, they usually take a lot of impact from jumps and such like. But after resetting everything, if it still plays up, might be e warranty job?

 

[Kla912000]

Watch this video. This might be what your problem is

 

[m71295]

Watch this video. This might be what your problem is

This was it my friend ! Thanks so much ! Now the only thing that`s left is to find what servo saver and arm fit my servo Savox 1210SG Can`t find any stock from the 25T arrma part though. I`m looking for alternatives and they recommended me the Kimbrough 123 or 124 but i like it when things are done right. On top of that i gotta pay much for delivery for that one so i will wait i guess or get a Team Corally one if they will fit. Hot racing i also cant find in stock

First thing I’d do is check transmitter is still bound. Then I’d reset the esc. Then set the end points for the servo and throttle.
Manual should tell you how to do it on the Big Rock. Person doubt the esc is faulty, they usually take a lot of impact from jumps and such like. But after resetting everything, if it still plays up, might be e warranty job?

It was my throttle on the remote that wasn`t centered. Whoooh... I`m happy because i kinda ruined my warranty by destroying my servo horn by drilling a hole on the opposite side to remove the cap (found no other way) and then placed a cap with 25T so it can fit my new servo. It worked, i fitted it but when i tighten it it isn`t very horizontally right but i can fix that with a bit more of DIY patience. So i got steering now but i`m waiting to see what replies i`ll get from EURO RC if any other parts are available. They recommended me the 123 and 124 Kimbrough but i am looking for something esle since i can`t find them cheap enough and in stock.

 

[m71295]

Is any of these gonna do or same story like k 123 and k124 ones ? Can someone take a look at this website eurorc.com ?

 

[Kla912000]

If you can get the Kimborough 123, then get it. It is a direct fit with no modifications and comes with adapters for 23t, 24t, and 25t servos.

Glad you got your ESC working.

 

[m71295]

If you can get the Kimborough 123, then get it. It is a direct fit with no modifications and comes with adapters for 23t, 24t, and 25t servos.

Glad you got your ESC working.

https://wheelspinmodels.co.uk/i/8210/ is this it?

 

[Kla912000]

https://wheelspinmodels.co.uk/i/8210/ is this it?

Yes, that is the correct one.

 

[m71295]

Yes, that is the correct one.

We ordered the last one available. So these 3 adapters... do we need to glue anything ? How does it work ? The stock one had a spring inside but in order to open a cap i had to drill a hole on the opposite side of it kind of ruining it but it was literally the only way and after we opened it up the spring popped out and we had to force it back in and create a filling underneath it but when we attatched the improvised servo saver (with the 25T cap from the savox 1210SG package) it didn`t align 50/50 horizontally and it stays to one side. I guess it is because the spring inside is not equally put because the filling is different. I tried filling it multiple times with different materials but it always stays to one side when tightened. I hope i don`t have to do additional work with this one.

 

[Kla912000]

No gluing. Just put the little 25t adapter on the servo and put the Kimbrough 123 right on top of it. You'll figure it out when you get it. Power the servo on before you put the servo saver on, then put the servo saver on lined up the best you can with the arrow on the servo mount then use steering trim to center it perfectly.

 

[m71295]

No gluing. Just put the little 25t adapter on the servo and put the Kimbrough 123 right on top of it. You'll figure it out when you get it. Power the servo on before you put the servo saver on, then put the servo saver on lined up the best you can with the arrow on the servo mount then use steering trim to center it perfectly.

Thanks ! I`ll post an update when it comes.

 

[m71295]

Ok now... I have one traxxas servo saver and the kimbrough 123. How do you call this compatible if obviously it will hit the sides in the box wall when turning ? The traxxas one is even smaller but it still touches. You can see the original the kimbrough and the traxxas one on the photo.

So what do I do ?

No gluing. Just put the little 25t adapter on the servo and put the Kimbrough 123 right on top of it. You'll figure it out when you get it. Power the servo on before you put the servo saver on, then put the servo saver on lined up the best you can with the arrow on the servo mount then use steering trim to center it perfectly.

I posted. Can you check it out ?

 

[Kla912000]

Ok now... I have one traxxas servo saver and the kimbrough 123. How do you call this compatible if obviously it will hit the sides in the box wall when turning ? The traxxas one is even smaller but it still touches. You can see the original the kimbrough and the traxxas one on the photo.

So what do I do ?

View attachment 141302

View attachment 141303

I posted. Can you check it out ?

It does not hit the side of the box. It comes close but it doesn't hit. Turn it and you will see. But, I have a different servo also which might give mine a little more clearance than yours. Even so, it's no big deal! If it does barely rub simply get a razor and trim a tiny bit off of the corners. It's not that hard to figure out!!!

 

[m71295]

It does not hit the side of the box. It comes close but it doesn't hit. Turn it and you will see. But, I have a different servo also which might give mine a little more clearance than yours. Even so, it's no big deal! If it does barely rub simply get a razor and trim a tiny bit off of the corners. It's not that hard to figure out!!!

Following the same logic i guess i gotta drill a bigger hole into it because the screw won`t go through it otherwise. It`s too thick.

 

[Kla912000]

Wow! You're really overthinking this and making it harder than it has to be. Just calm down and put it together. You might need a longer screw. You might have to trim an edge. I don't know. Each application is different. That's all part of the hobby. Modifying things to make them work. When you can't get the stock part you have to go to the aftermarket and make it work. Mine fit perfectly. Yours might not. Just make it work, or you can wait 6 weeks for the stock Arrma servo saver.

 

[m71295]

Wow! You're really overthinking this and making it harder than it has to be. Just calm down and put it together. You might need a longer screw. You might have to trim an edge. I don't know. Each application is different. That's all part of the hobby. Modifying things to make them work. When you can't get the stock part you have to go to the aftermarket and make it work. Mine fit perfectly. Yours might not. Just make it work, or you can wait 6 weeks for the stock Arrma servo saver.

Okay so I trimmed the shape of the part in order to get more steering ratio and I'm still not getting a lot but I guess that would be the maximum I'll get until the arrma part comes. Even though the servo is 27kg is it normal to be making such sounds when you let go off the remote after turning. It has trouble bringing it back to 100% neutral when I turn to one side and let go off the remote.. I'm asking this question because this is my first servo change and it is a 98 euros servo so I wouldn't wanna break it. I cant afford calibrating the servo though since it will touch the esc box when turning to the left when having the steering trim on 100%. I even made this video so you can see

And some photos of the trim I made as well. Mixed up sides at first though. Hopefully it wont break because it is a pretty close cut next to the hole for the servo arm screw.

 

[razorrc]

The servo saver you bought is too weak. That's why the wheels don't turn all the way when you turn the steering wheel.

 

[m71295]

The servo saver you bought is too weak. That's why the wheels don't turn all the way when you turn the steering wheel.

The servo saver is Kimbrough 123 and it is the only option there was. It is incompatible but it's what will work for now. Are you kidding me ? How can a saver be weak. It's just a piece of plastic. I saw the sound actually may be normal from other videos. You have any idea if any metal servo savers are compatible with te big rock ? I cant find the hot racing in stock. And what's left for the Arrma saver ? I'll be getting that one too which is still plastic ? Where is the logic to be weak ?

 

[razorrc]

I mean the spring inside is too weak. The servo saver "saves" your servo by giving/releasing when your servo is pointing the wheels in one direction, but something else (say a curb/tree/crash) tries to turn the wheels a different direction. It gives, so that you don't destroy your servo by forcing it to move differently than what the wheels are trying to do.

In this example, the servo saver is so weak that it can't even turn the wheels all the way due to the resistance/friction of the tires rubbing on the ground. Notice that when you lift the tires up, the wheels turn all the way. The servo makes that whining noise because the spring on the saver isn't strong enough to turn the wheels, but still strong enough to push against the servo, putting a continuous strain on it.

They make weak ones, and stronger ones. The extra strong Kimbrough is an example of a stronger servo saver -- https://bit.ly/3ggvnmo