This one is nuts

[hbj069]

Bec set @ 7.4 volts
Futaba 6114ff receiver
Futaba 4pks

Red and black wires going into bec power supplied by external battery (charged)
connector side of BEC red wire goes to red on 7950 servo black to black, tan wire (signal) plugged into receiver,

It does not work??
tried 3 bec's all good,
tried 3 receiver's, all good
tried 2 servo's, all good

I have this exact same set up on both comp crawlers and my jeep and it worls fine.

Help

[Charlie-III]

OK, you say it does not work, but then you state in 3 tests all are "good".

I'm not following.

In the rig in question, did you try just plugging the servo into the RX? This would make sure the TX, RX & servo are all good in the rig.
Then unplug the servo from the RX & set back up on the external BEC, try again.

Sorry If I'm not understanding your issue.

[hbj069]

everything is testing fine, will not work when combined in this rig, If I remove bec and plug the power wires of the servo into the rec everything works fine?

[Grandmasboy]

Hey Joe, just curious why you're hardwiring the servo when that rx can handle 7.4 volts?

[hbj069]

Its on ellie mae and with the rear steer it gets a touch heated? Figured i would run the front off of ext bec and fix it that way.

[Grandmasboy]

Makes sense now.

[Trubble]

Originally Posted by hbj069

connector side of BEC red wire goes to red on 7950 servo black to black, tan wire (signal) plugged into receiver,

Are you running the BEC's signal wire into the receiver?

Or do you mean to say the servo's yellow wire going into the receiver?

You're black to black BEC to servo, do you also have a black going into the receiver?

[JeremyH]

Originally Posted by Trubble

Or do you mean to say the servo's yellow wire going into the receiver?

That's what I was wondering as well...

If so, Joe, are you sure it is plugged into the signal port on that channel?

[ik632]

Is it wired like this:
An Axial Crawler Blog - Get Your Wraith On

It sounds like you're missing the ground to the servo.

[Charlie-III]

Originally Posted by ik632

Is it wired like this:
An Axial Crawler Blog - Get Your Wraith On

It sounds like you're missing the ground to the servo.

If it was a Spektrum, I would be concerned with the grounds between the servo, BEC & RX.

It's a Futaba, not normally an issue. If it was an issue, it's usually a glitch, not a "it won't work".

[JeremyH]

Originally Posted by ik632

Is it wired like this:
An Axial Crawler Blog - Get Your Wraith On

It sounds like you're missing the ground to the servo.

I have quite a few rigs wired exactly as Joe posted (without the ground from servo to Rx) and not an issue with any of them.

[chicklet]

For a hitec servo, shouldn't the yellow wire be the only wire plugged into the receiver (if its hardwired to the BEC)?

[chicklet]

The yellow wire from the hitec servo should be the wire plugged to the RX. The BEC gets its power from the battery, then (the BEC) hard wires to the servo to give the (servo) power. The yellow wire from the servo, gets signal from the RX. So the tan wire is void? I don't like hard wiring my servos and BECs.

[hbj069]

Originally Posted by Trubble

Are you running the BEC's signal wire into the receiver?

No.

Or do you mean to say the servo's yellow wire going into the receiver?

Yes the tan/Yellow, signal wire. I have tan one one servo and yellow on another.

You're black to black BEC to servo, do you also have a black going into the receiver?

No.

Originally Posted by JeremyH

That's what I was wondering as well...

If so, Joe, are you sure it is plugged into the signal port on that channel?

Yes sir, just like our comp rigs.

Originally Posted by Charlie-III

If it was a Spektrum, I would be concerned with the grounds between the servo, BEC & RX.

That's exactly what I am thinking, maybe the older futaba rec's have an issue?

It's a Futaba, not normally an issue. If it was an issue, it's usually a glitch, not a "it won't work".

Well I can't find the problem, I hooked up the ext bec to the rec to try and power both servos with it, works fine that way, yes gents I removed the esc red wire. Will chat with Harley about it in the future and post results. Thanks for all of your replies

[hbj069]

Originally Posted by chicklet

For a hitec servo, shouldn't the yellow wire be the only wire plugged into the receiver (if its hardwired to the BEC)?

Correct.

Originally Posted by chicklet

The yellow wire from the hitec servo should be the wire plugged to the RX. The BEC gets its power from the battery, then (the BEC) hard wires to the servo to give the (servo) power. The yellow wire from the servo, gets signal from the RX. So the tan wire is void? I don't like hard wiring my servos and BECs.

Also correct, that's what I am doing, it just don't make sense!

[chicklet]

It still doesn't work?

[chicklet]

I looked at an old BEC I had laying on my bench. The tan and red were used, orange cut short. This is jogging my brain...

[hbj069]

But it works on both comp rigs.

[chicklet]

Weird

[SuperRoo]

Does it work if you disconnect the rear servo?

Are you running 4WS in the comp rigs that this setup works in? or a single servo?

The problem reads like a problem when both F/R steering servos are connected at the same time. Rear wired normally to the RX and Front running single RX wire only.

Possibly a ground loop or interference issue.