X4R receiver seems to be stuck in CPPM output mode

[Allan Bennett]

I have an X4R receiver which I previously used in a quadcopter, with CPPM 8-channel output from slot 1, and PWM channels 9-11 from slots 2 to 4.

I now want to use it in a fixed-wing model, and have re-bound it to the new model position in my Taranis transmitter, without any jumper in place, but whichever function I assign to channel 1, a servo plugged into that channel doesn't respond.

I've achieved what I want by using only channels 2, 3, and 4 for ailerons, elevator, and throttle respectively, but it would be nice to have channel 1 available so that I can have separate channels for the two ailerons instead of a Y-lead.

Thinking about it as I write this, it surely can't still be in CPPM mode otherwise I would have to be using channels 9-11 for my outputs instead of 2-4. So maybe my receiver is u/s? Any thoughts please?

[Denis Watkins]

The small contribution I can make Allan, for RC in general

The Tx is set to Heli and not Fixed wing, as these use channel 1 differently

[Allan Bennett]

Thanks for the suggestion Denis, but the transmitter is programmed for a simple 3-channel fixed-wing (no rudder) aircraft.

[Bob Cotsford]

Allan, if you rebind in CCPM does it give you the expected output from ch1? This would at least confirm that the hardware is probably ok.

[Allan Bennett]

No opportunity to check it today, but I'll check it with an old flight controller board when I get the chance. The quad it was in is now using a FrSky combined receiver/flight controller board.

[Bob Cotsford]

It might be worth flashing it with the latest firmware.

[Allan Bennett]

I'll have to read up how to do that. My philosophy so far has been "if it ain't broke, don't fix it", so my transmitter is on v.2.1.9 and my receivers (all EU LBT) are all on whatever they were on when they were bought. Will updating a receiver then require my transmitter to be updated?

[Attilio Rausse]

Hi

Seems that you may have the X4R-SB which has CH1 dedicated to SBUS and 3 other PWM channels, just a thought.  Can't be changed (ie software update).

Edited By Attilio Rausse on 11/07/2018 16:00:15

[Allan Bennett]

No, Attilio, it's definitely the X4R, with a white wrapper. When bound with no jumper it should be a simple 4-channel receiver without any CPPM or SBUS.

This afternoon I flashed it with the latest firmware from FrSky (RX4R_LBT180516.frk), via my Taranis transmitter, as described in an article on TechWit web site. All went smoothly but, after re-binding it to my Taranis, the result is still the same -- any servo connected to channel 1 goes to full throw when the receiver is powered, and doesn't respond to any input from the transmitter.  The other 3 channels work fine.

Thinking about it, there's only one X4R firmware shown on the FrSky web site -- no separate one for the X4R-SB that I can see. Any chance I've inadvertently converted my X4R into an X4R-SB by flashing it?!?

Edited By Allan Bennett on 11/07/2018 16:22:14

[Bob Cotsford]

I'm pretty sure SB is on ch4. Whether it's SB or 4ch is decided by a jumper (0 ohm resistor) on the receiver pcb, as per this article.

Incidentally, I seem to remember all my X4Rs being in white whether Sbus or vanila.

Edited By Bob Cotsford on 11/07/2018 16:45:53

[Mike Blandford]

The RX4R is a different receiver, the X4R is on the second page of receivers and there is more than one firmware download listed.

If you go to the "bars" display on the Tx, is bar for channel 1 moving?

It may be worth creating a new model on the Tx, if you haven't already done so, to rule out any odd settings on the Tx causing the problem.

Mike

[Allan Bennett]

I now see I needed to 'Load more' several times to find the standard X4R receiver download, so I've now downloaded and flashed the latest one, X4RSP_EU_170322.frk, and the result is the same as before -- nothing working on channel 1.

Bob, the article you've linked states that the standard X4R is white while the SBUS version is black, which is what I had understood from what I saw advertised on T9's web site. Mine's white, and is definitely plain vanilla.

The bars for channel 1 and 2 are moving in unison in OpenTX Configurator. I can't find an equivalent display on the transmitter itself, but I'll create a new model tomorrow as a final check. Otherwise I have to conclude that the receiver is now faulty, and it's not worth risking using it even though channels 2-4 seem to be working correctly.

Edit: Sorted!

You've hit the nail on the head Mike; I copied a previous 4-channel model as the basis for this one, but the one crucial difference is throttle was on channel 1 in the previous model, and has a throttle-cut switch which I forgot to reprogram to work on channel 4 instead.  So all my tests were with the throttle-cut activated (for safety), but in fact all it was doing was shutting off channel 1 instead of the new throttle channel, which is 4.

Edited By Allan Bennett on 11/07/2018 20:38:31