How to connect SBUS receiver to SK 720 BE

[filtr]

Hi Folks

I thought I would post pictures of how to connect a futaba Sbus HV receiver to a SK 720 BE. As you can see by the pictures. It is not a hard process. But it is not explained to well in the instructions. I used a 2 cell lipo to connect direct to the SK 720 BE port SW A port direct with a switch in between the battery and the SK 720. From their you content the SBUS wire from the SBus port on the receiver to the IO-B port. Then plug the servo leads into the SK 720 as require by the instructions.

Thanks to the Brandon at Skookum for walking me throught the process. I was stump because the instructions really do not explain this for the new SK 720 BE.

[Arcturus97]

This works but two wires into the RX is not necessary (on the 540 anyway). The RX itself uses so little power that the one cable in the SBUS port to the SK is sufficient for both power and signal. I'm running both my SK-540s with just one cable to the SBUS RX. Is the IO-B port wired differently on the BE relative to the 540?

On the other hand I'm using two cables from the RX battery to the SK-540 so the load of all the servos is carried on two cables instead of choked through one. Check out the how to in the current issue of RC Heli Pilot magazine they show how to make your own power cable from RX battery to servos that is even better, I'll sum it up:
Start with thicker wires downstream of the battery, take 2 heavy servo extensions and separate the wires from each other in the middle, cut the red and black wires so you now have 4 red ends and 4 black ends, leave the signal wires intact, solder all 4 red ends together to the red wire downstream of the battery, solder the black wires next, heatshrink, plug two of the servos into the ends of the extensions, plug the other 2 ends into the appropriate port on your FBL unit. You now have the battery supplying power directly to two of your servos on their individual halves of the extension wire, the other half of the two extension wires goes from battery to FBL power bus and can supply the remaining servos. Yeah there are more solder joints here but your servos won't be starved for power. I'll be doing this method on my next build.

[JBajkor]

Thanks filtr, that's just what I needed.

[JTAnimal]

I also had problems with this. Most of us that use Futaba and use a SK720 Blue or original, know about the S-Bus adaptor (a extra $11.00)
When I received my SK720 Black I hooked it up using the S-bus adaptor, and nothing. tried several time and still it would not work, I was at the point of saying, I must have a bad SK unit. I even pulled the S-Bus adaptor out of my Trex 550 (I knew it was working) and still the black would not work with the Futaba S-Bus. I was so bummed, it was the Friday, July 5th and I was a fired up to fly on Saturday, that did not happen.

I posted the question here and Art did reply later that night, "hook a straight line to IOB just like on the 540" (like I own a 540) ok stuff happens I got it working. And I'm sorry to rant but, I expected better from a high end unit.

The question I still have is I am using the 720 black on a Goblin 700, do I still need to use the power bus? the Goblin has very little room and that power bus is a space hog. if its not needed then I would pull it out. If I need it than ok, or if the vibs still would be a problem without the power bus, then ok. I thought the new acc would be less problematic with vibrations!

[filtr]

Originally Posted by Arcturus97

This works but two wires into the RX is not necessary (on the 540 anyway).

I need to have a source of power to the receiver. That is one set of wires and the other is the sbus.

[filtr]

[quote] I also had problems with this. Most of us that use Futaba and use a SK720 Blue or original, know about the S-Bus adaptor (a extra $11.00) [QUOTE]

Only need this adaptor for the SK720 Blue and not for the Black SK 720.

The question I still have is I am using the 720 black on a Goblin 700, do I still need to use the power bus? the Goblin has very little room and that power bus is a space hog. if its not needed then I would pull it out. If I need it than ok, or if the vibs still would be a problem without the power bus, then ok. I thought the new acc would be less problematic with vibrations!

I am not using the power bus just going directly to the SK 720 unit but I am using HV servos and recievers.

[Arcturus97]

Originally Posted by filtr

I need to have a source of power to the receiver. That is one set of wires and the other is the sbus.

The sbus cable (1 set of 3 wires) holds both power and signal

[filtr]

I will have to try that tonight. If I remeber the power through just the sbus did not power the receiver. It would make for one less wire.

[JTAnimal]

[quote=filtr;5152406][quote] I also had problems with this. Most of us that use Futaba and use a SK720 Blue or original, know about the S-Bus adaptor (a extra $11.00)

Only need this adaptor for the SK720 Blue and not for the Black SK 720.





I am not using the power bus just going directly to the SK 720 unit but I am using HV servos and recievers.

I am also using HV servos and HV RX, so you think its ok to get rid of the power bus? the only reason I used the power bus was the old rule from the SK blue (they said use a power bus for anything above a 500 size)

[Xrayted]

[quote=JTAnimal;5153727][quote=filtr;5152406]

I also had problems with this. Most of us that use Futaba and use a SK720 Blue or original, know about the S-Bus adaptor (a extra $11.00)


I am also using HV servos and HV RX, so you think its ok to get rid of the power bus? the only reason I used the power bus was the old rule from the SK blue (they said use a power bus for anything above a 500 size)

Yes. It never was about voltage, but to reduce vibrations from the heavier cables typically used going into the unit. Both the old 720 and the black can handle direct HV setups just like the 540 can.

My Goblin has a Black with no power bus at all and all HV setup, with no vibe issues. I did cut down the three ally pins the under the gyro plate to lower the unit. The thicker metal plate puts the gyro just under the canopy edges, which was too close for me.

[filtr]

Originally Posted by Arcturus97

The sbus cable (1 set of 3 wires) holds both power and signal

I Tried it last night with out the power wire and only the SBUS wire and it lights up the receiver.

I think this was a carry over from the SK 720 Blue unit where you need the power wire.

[Arcturus97]

Originally Posted by filtr

I Tried it last night with out the power wire and only the SBUS wire and it lights up the receiver.

I think this was a carry over from the SK 720 Blue unit where you need the power wire.

Good deal, glad it works on the BE (my setup is 540)

[sl4ppy]

<EDIT> nevermind.. Missed the high voltage bit. <EDIT>

Im a bit confused by the OP. I have a single regular connector cable from my SBus straight into the port on the 720BE. No special cable, or anything..

SBUS out directly to IO-B with a standard cable. Nothing else.

[tyler777]

[quote=Xrayted;5154161][quote=JTAnimal;5153727]

Originally Posted by filtr

Yes. It never was about voltage, but to reduce vibrations from the heavier cables typically used going into the unit. Both the old 720 and the black can handle direct HV setups just like the 540 can.

My Goblin has a Black with no power bus at all and all HV setup, with no vibe issues. I did cut down the three ally pins the under the gyro plate to lower the unit. The thicker metal plate puts the gyro just under the canopy edges, which was too close for me.

Hi Xrayted .do you know where I can find in depth info on how to connect the sk 720 to the futaba s bus

[tyler777]

Hi guys,
how do I connect sk 720 to futaba s bus receiver with a receiver pack.thanks