Hope someone can help...

I'm converting my 150cc Yak over to 2.4GHz. I have a Dual Rx version of the SmartFly Ignition Cutoff (SIC). The setup worked perfectly on the previous dual 72MHz receiver system. With the dual SIC, either Rx would control the cutoff.

Now, I am installing dual JR R921 2.4GHz receivers. When I connect one of the two lines from the SIC to the channel set for cutoff, works fine. I can do the same with either Rx module. I can criss-cross the SIC input lines between the Rx units, still works one at a time. However, when I connect BOTH SIC Inputs into BOTH Rx's at the same time, the SIC flashes and is indicating a fault.

Per the instructions, I have verified that there are no bad connections, battery power is adequate, and everything is programmed properly. I put a servo on the each Rx units and verified that the channel is providing the same signal direction from both Rx units. Everything appears to be wired properly.

So, it seems that somehow the JR R921 receivers are conflicting with each other. I assume because they are connected to a common power source (Powerbox Royal, PBR). It didn't do this on the old 72MHz JR Rx setup, wired exactly the same way. The SIC is wired direct to each Rx output, not thru the PBR.

I pulled the center positive lead out of one side, no change. This SIC is about 3 years old. I don't see any revision markings.

Does anyone have an idea how to solve this problem? Is there an updated version that deals with this more recent 2.4GHz Rx circuitry?

Any help would be appreciated...

Thanks!

Hi,
The error indicates that the unit saw conflicting information from the two receivers. This can happen because the failsafe is not set the same in both receivers (since JR sets failsafe in the receiver instead of the transmitter as other radios do and all the old PCMs did). The other issue could be the way the receivers power up but I have not had any issues with any other 2.4GHz radios running dual receivers. There is nothing special about 2.4GHz as far as the Cutoff is concerned. The unit will operate correctly even though it flags a fault. It is just letting you know that it saw conflicting commands from the two receivers.

Thanks for the feedback, much appreciated. I know I set the fail safes once , but I have not re-tested them after the Rx install and a re-linking. That makes sense, although when I put a servo on the cutoff channel the servo behaved the same on start-up on both Rx units. Maybe there is a momentary thing the servo is not responding to. I'll post results after checking the fail safe conditions.

Thanks!

Okay Ritchey, I have it working properly now.

Unfortunately, I'm not sure which fixed the problem. Before I reset the fail-safes, I noticed the PowerBox Royal (PBR) was showing one Rx was offline. The link lights on both Rx's were on and solid, but the PBR didn't agree. I noticed that the channel that was indicating dead (the Rx indicator was not reverse color) was on the same side of the system that I had neglected to connect a battery.

Hmm, reading the PBR manual, there is no mention of this. After a little experimenting, I noticed that you must have both battery circuits connected at boot so the system will indicate both Rx's are connected and live (PBR has Dual Battery input with sharing and auto switching). If you only have one battery connected, which is how I was testing, that side of the PBR does not indicate a good Rx connection for that side. You can disconnect one side after boot, and it's all good. It's just at boot time that this happens.

So I fixed that, and then I reset the fail-safes. Now, the SmartFly Ignition Cutoff is indicating normal conditions. Light goes on-off with the switched channel cycling. To be honest, I didn't think to check the fault before the re-link, so it could be that either correction could have fixed the problem...

Either way, problem solved. Thanks for your help.

I saw this late, and all I was going to respond with was "Call Bob!" Looks like he beat me to it and has you working. That's why you buy SF - GREAT support!