Orange R620X V3 Rx won't bind to a DSM2 Tx

Most of my flying is with Futaba gear but I have an original Spektrum DX7 Tx which is of course DSM2. I use this Tx with my indoor models equipped with Orange and Lemon Rx's. I have an outdoor foamie which I wanted to use with the DX7 and I bought an Orange R620X V3 Rx for it. Problem is it won't bind to it. Going through the bind procedure and standing well away from the Rx, the Rx LED flashes rapidly with the bind plug in and when you power up the Tx in bind mode the light goes out and that is it, nothing else happens. I tried binding it to a friend's DSMX Tx and it bound normally. The Rx says DSM2 and DSMX on it and this is also stated in the instructions. Has anyone else had this problem? is it really only a DSMX Rx?

I have only used R620s on DSMX TXs, but, one of mine refused to bind indoors.

Perhaps there was other background radio noise (wifi?) making a problem, 2.4GHz can be a busy band, but outdoors it was ok.

On the back of the R620, Alan

Does it say CPPM or S.Bus output

As they cannot be both, supplied as either CPPM or S.Bus output

I've just taken a look at the Rx and it says CPPM on the back. It just occurred to me that I do actually have a DSMX Tx as I have a RTF Blade 70S heli. It bound with no problems to the Blade Tx and the 4 main channels worked servos as expected. Tried to bind with two different DSM2 Tx's and no joy. The question is whether there is a special binding technique for use with DSM2 (nothing mentioned in instructions) or is the statement on the Rx itself and in the instructions that it works with both DSM2 and DSMX incorrect.

You have covered it Alan, and it is not obvious why the pair won't bind for you.

I too use DSM2 for indoor as early plug and play models were DSM2

No disrespect, but does the DX7 have a good battery pack and check it for antenna connection, as some have a

press stud fitting to the board that can come away, this disconnecting the signal,

And remarkably have had 1 antenna snap internally drastically reducing the range.

Am clutching at straws

Yes the DX7 has a good Eneloop pack currently showing 10.3V on the Tx and the RF output shows a healthy reading on my 2.4GHz field strength meter. Ideally I would like to find someone with the same V3 Rx and a DSM2 only Tx, might not be a long wait! I suppose I could contact Hobbyking but I wouldn't hold out much hope of getting useful advice. I don't think the Rx is actually faulty as it works fine with DSMX transmitters. I might end up selling to a club member who uses Spektrum (plenty of them).

Longshot, but have you tried moving further away 3-5m? which worked with my DX 9 when I experienced a binding issue with a Lemon RX.

I tried going into another room but that would not be as far as 3-5m. When I get a chance I will try it down the length of the garden. I am not very hopeful this will make a difference as it had no trouble binding to a DSMX Tx but I will give it a go.

Don't forget your TX also has an RX inside it, so the comparison with another TX is not so simple. And the RX has a TX in side it too

Outdoors is generally better as far as radio noise goes.