Deltang Rx61-22-W - Please help

[Corbs]

Alas! After the loco suffered some hardware woes (schoolboy error of matching a coarse worm gear to a fine axle gear resulting in one stripping the other, now rebuilt with fine gears on both) I got it back together again and it's back to being very unreliable. I've tried it with the connections on the motor reversed and so far it seems to do the runaway in only one direction (currently when going backward). However rather than only doing it on full throttle as it did yesterday, it does it at half throttle now.
When it runs away, the LED on the Rx flashes slowly rather than solid light as I previously thought, which makes me think it is along the lines of it losing signal, as the flashing speed is the same as when you are binding it.
This test was with the controller next to the Rx, and the mended aerial fitted.

 

I've ordered some more Rx41 receivers and may try one of them on this. The chassis also has a tight spot in one direction which is frustrating.

[davetheroad]

Right ,lets find out the problem by elimination of the possibilities. It could be the Rx, the Tx or the loco

 

1. Remove the battery and Rx from the loco and test without a motor connected, don't forget to insulate the ends of the wires! Has the problem gone away? If YES it looks like a loco problem? Fit back to the loco, does the problem recur? If yes it is the loco If NO it could be the Rx or the Tx

 

2.If you have another Rx 61 test that off loco, if it works OK fit it to the loco, does the problem recur, if YES it IS the loco

 

3. If the alternative Rx/Tx combo shows the fault which is it? Maybe the Tx

 

I have just tested 7 Rx's with 2 Tx's, Two Rx62, Three Rx61 and two Rx60. I tried turning the pot as fast as I could from 100% forward to 100% reverse. the LED stayed solidly on and the loco did not run away.

 

Are you in the UK? If so and you still have the Tx/Rx combo problem you could post the Rx to me and will test it with my Tx's, I have 5 of them!. Contact me if you want to try that.

[Corbs]

Right ,lets find out the problem by elimination of the possibilities. It could be the Rx, the Tx or the loco

 

1. Remove the battery and Rx from the loco and test without a motor connected, don't forget to insulate the ends of the wires! Has the problem gone away? If YES it looks like a loco problem? Fit back to the loco, does the problem recur? If yes it is the loco If NO it could be the Rx or the Tx

 

2.If you have another Rx 61 test that off loco, if it works OK fit it to the loco, does the problem recur, if YES it IS the loco

 

3. If the alternative Rx/Tx combo shows the fault which is it? Maybe the Tx

 

I have just tested 7 Rx's with 2 Tx's, Two Rx62, Three Rx61 and two Rx60. I tried turning the pot as fast as I could from 100% forward to 100% reverse. the LED stayed solidly on and the loco did not run away.

 

Are you in the UK? If so and you still have the Tx/Rx combo problem you could post the Rx to me and will test it with my Tx's, I have 5 of them!. Contact me if you want to try that.

Hello Dave

 

Thank you for your help with this.

I've tried it with 2 motors with the same results.

 

1 - I don't really understand what you mean when you say to test it?

2 - I have an Rx61 fitted to another loco which works well.

 

I do have several Rx41 on order now so I can try one of those next week.

[Corbs]

Little update....

I tried binding the Rx to a different setting on the Selecta, but this wouldn't work and I got only the double flash.
Then I tried the Rx on a 12v motor - no running away! Perhaps this is the issue, that the 3v motor draws too much current as you suggested?
I have some 6v motors on order which may split the difference, definitely something to try.
So far I haven't had to re-bind the Rx and Tx but I'll try leaving it for a while and test again later.

[BG John]

I'm adding a current sensor to my Arduino based DIY RC system. I don't know if I'll always use it, as it takes up extra space, but having the option seems useful. It will be wired in series between the battery and the Rx. It might be worth making up a data logger that you can attach to locos you're testing. An Arduino Nano, MAX471 sensor and an SD card data logger board would be cheap, and would fit in an open wagon coupled to the loco. Add a couple of resistors, if you're using more than 5 volts, and you could log the voltage too. With extra sensors, you could log more possibly useful data.

[davetheroad]

Little update....

I tried binding the Rx to a different setting on the Selecta, but this wouldn't work and I got only the double flash.

Then I tried the Rx on a 12v motor - no running away! Perhaps this is the issue, that the 3v motor draws too much current as you suggested?

I have some 6v motors on order which may split the difference, definitely something to try.

So far I haven't had to re-bind the Rx and Tx but I'll try leaving it for a while and test again later.

Actually it was DavidT of Deltang that suggested this on the FreeRails site and I just confirmed that  a small battery can have surprising voltage sag under load. Anyway it appears you have found the problem, the motor in the loco. 

 

I have a 0-4-0 Hornby Smokey Joe that uses a Deltang RX and a single lipo. It uses the standard motor and I get a top speed of about 20mph. I improved slow speed performance by using low off throttle control and adjusting the PWM frequency to 120Hz. The 70mAh battery lasts about 30 minutes with is fine for its normal role of shuffling gypsum wagons on and off layout.

[Corbs]

Yes sorry I was copypasting the post from freerails. I think your Smokey Joe might perform like my other RC locos, great for shunting. I do find that they need just a little more top speed, so I am hoping the 6v motor will give the best of both worlds.

[Corbs]

(crossposted from freerails)

Unbelievable! My other Rx-61 has also started to play up. It just will not bind to the Tx. When I try to bind it, I get a solid light for about a second, then straight back to the 2 flashes every 1 second.
So frustrating!

Edit: Well that'll teach me. Switched selecta position to a completely different one and it bound straight away! Doh....

Edited August 19, 2018 by Corbs

[davetheroad]

(crossposted from freerails)

Unbelievable! My other Rx-61 has also started to play up. It just will not bind to the Tx. When I try to bind it, I get a solid light for about a second, then straight back to the 2 flashes every 1 second.

So frustrating!

Edit: Well that'll teach me. Switched selecta position to a completely different one and it bound straight away! Doh....

 

Have you tried binding it back to the original selecta position?

[Corbs]

Have you tried binding it back to the original selecta position?

Ah, no I have not, I was so excited to be using the loco again!