Lost in a TRX4M build

[Lostinthewoods86]

Hmm. Wonder if the servos were experiencing brown out from not getting enough power.

I got them powered directly from the battery. It was fine with the stock motor. When I swapped the other servo I powered it through the receiver and it was fine. Kinda weird. Wondering now if I should try to power the problem servos through the receiver and see if it does it.

 

[WickedFog]

I got them powered directly from the battery. It was fine with the stock motor. When I swapped the other servo I powered it through the receiver and it was fine. Kinda weird. Wondering now if I should try to power the problem servos through the receiver and see if it does it.

Powered from the battery how?

 

[Lostinthewoods86]

Powered from the battery how?

They soldered to the battery plug

 

[WickedFog]

View attachment 189355
They soldered to the battery plug

Wow. That's factory? That's really strange.

 

[Lostinthewoods86]

Wow. That's factory? That's really strange.

Home brewed

 

[WickedFog]

Oh. What battery you running? And what servos?

 

[Lostinthewoods86]

These batteries. I cut both connectors off and both leads soldered to xt60 plug (two reasons, one it’s what I had, two it’s what my charger is ).

They ramp crab servos. Swapped with the Injora one and it was fine at 6 volts

But it’s weird it worked fine before with the factory motor/trans. One thing I’m not sure it if it went swimming. Son was out playing in the mud with it before we did this

 

[WickedFog]

Could be the receiver has moisture in it. Or maybe the servos got wet. But strange both servos would go out like that. The motor swap could be drawing more amps, especially with the 2-spd trans. Maybe moisture in the Rx is causing problems. That would be the first place I would look.

 

[Lostinthewoods86]

Could be the receiver has moisture in it. Or maybe the servos got wet. But strange both servos would go out like that. The motor swap could be drawing more amps, especially with the 2-spd trans. Maybe moisture in the Rx is causing problems. That would be the first place I would look.

It is strange, but it was working just fine before the swap, and it works fine with just the Injora servo on the front (I just disconnected the rear cause he was bummed he couldn’t drive it and he ran a couple batteries through it in the house). I may just swap the other Injora one or get a couple different servos, the horns are different and it’s just rigged up for now on the front. I think I’ll try to power them through the receiver tho too just for my own curiosity

 

[Lostinthewoods86]

@WickedFog i put the problem servos back in, powered them through the receiver at 6 volts and it’s fine

Also a little more to the story, so I powered them the way I did because the servos came with little jumper harnesses to do basically what I replicated, but since I ditched all the factory electronics I just made my own. They recommended to run the servos at battery voltage. It was always kinda chattery steering before at full voltage, it’s actually a lot smoother now at the 6 volts

 

[WickedFog]

@WickedFog i put the problem servos back in, powered them through the receiver at 6 volts and it’s fine

Voltage brownout somehow. Maybe because the caps in your ESC are holding reserve power for when you have a high demand. Wiring the servos straight to the batteries omits those.

Or maybe they don't like the full charge voltage of your batteries

Those Ramp Crab servos 8.4v capable?

 

[Lostinthewoods86]

Voltage brownout somehow. Maybe because the caps in your ESC are holding reserve power for when you have a high demand. Wiring the servos straight to the batteries omits those.

Or maybe they don't like the full charge voltage of your batteries

Those Ramp Crab servos 8.4v capable?

https://a.co/d/4CrMcd4

This is what I got and they were supposed to, they had harnesses included to do what I did

 

[WickedFog]

https://a.co/d/4CrMcd4

This is what I got and they were supposed to, they had harnesses included to do what I did

It could very well have just been moisture in the Rx. It doesn't take much. Swapping cables around may have eliminated it. Hard to say without further testing. But glad ya got it sorted.

 

[Lostinthewoods86]

It could very well have just been moisture in the Rx. It doesn't take much. Swapping cables around may have eliminated it. Hard to say without further testing. But glad ya got it sorted.

It’s almost got me curious enough to bring the scope home and see if I can see what the heck is going on

 

[WickedFog]

It’s almost got me curious enough to bring the scope home and see if I can see what the heck is going on

Hey, that's a great idear. Or take the truck to work

 

[Lostinthewoods86]

Hey, that's a great idear. Or take the truck to work

I’d have to bring it home, son would want to see it

I was wondering if I was getting some kind of rfi from the new motor on it. It was strange, with both suspect servos, running on battery power, just the front would trip out. Swapped the front to a servo that ran at 6 volt through receiver, rear still at battery, rear started tripping out, front was fine. Both suspect servos now on receiver power and fine. The curiosity is gonna kill me

Another edit: I had used the Traxxas original steering servo for my high/low shift servo, i was wondering if maybe I was pulling too much but it didn’t matter with it hooked up or not

 

[Weezel]

It’s almost got me curious enough to bring the scope home and see if I can see what the heck is going on

I'm curious as to what's going on. I know the higher voltage demands higher amps. And running through the receiver at 6v takes less amps.

 

[Lostinthewoods86]

I know the higher voltage demands higher amps.

Aint it the exact opposite?

 

[Weezel]

Years ago I thought so too. I was wrong also.

 

[Lostinthewoods86]

That website in the pic is highly suspicious to me personally.