Deltang Tx22 problems and solution

[philipy]

A couple of weeks ago I started to have problems with my Deltang Tx22 and the Rx's not finding each other when I switched on and had to keep rebinding each time. Eventually I worked out that although I could switch the loco's on and off without affecting the binding, as soon as I switched the Tx off, they all forgot each other.
I was talking to to Phil.P of RC Trains about another problem and mentioned this almost in passing. "Ah!" he said, "Some Deltang Tx2 modules develop a problem with their onboard crystals and that affects the stability of the binding. The only real answer is to replace the Tx2 module". Phil put one in the post to me on Friday, it arrived yesterday and my Tx22 is working perfectly this morning. Thanks Phil, that's service!

I did have one problem with installing the new module, and this may help anyone else who needs to do the same thing:

I thought it was just a straight replacement for the one in my Tx22 - swap each wire one at a time to the same pin on the new module. So I paniced when I switched it on and nothing happened, not even a light on the switch! So then I looked at the instruction paper and noticed that the 4 solder points on the LHS of the pcb appeared to be different to the one on my original. By some miracle I managed to find my original kit instructions from 10 years ago and eventually worked out that the Led wire and 3.1v supply wire have been moved around between the 4 pins ( there were only 3 on my old one). Rearranging them got the Tx working correctly!

[Lonsdaler]

Thanks for the heads up on this Philip. I have recently started to have some issues with my TX22, whereby control of my Boulton locomotive almost appears to be suffering from interference. I need to do more testing using other locomotives on the same TX first to see where the problem may lie.

[Phil.P]

Interference issues:
1. Servos tend to be things like trapped wires, on metal bodied loco's.
2. There are some really dreadful small electric motors out there.. Electrical noise from the motor can get back into the speed control, and confuddle it.

A ferrite on the motor leads, and a couple of 0.1uF ceramics on the motor, usually cure this.

Phil.P

[steveh99]

A couple of weeks ago I started to have problems with my Deltang Tx22 and the Rx's not finding each other when I switched on and had to keep rebinding each time. Eventually I worked out that although I could switch the loco's on and off without affecting the binding, as soon as I switched the Tx off, they all forgot each other.
I was talking to to Phil.P of RC Trains about another problem and mentioned this almost in passing. "Ah!" he said, "Some Deltang Tx2 modules develop a problem with their onboard crystals and that affects the stability of the binding. The only real answer is to replace the Tx2 module". Phil put one in the post to me on Friday, it arrived yesterday and my Tx22 is working perfectly this morning. Thanks Phil, that's service!

I did have one problem with installing the new module, and this may help anyone else who needs to do the same thing:

I thought it was just a straight replacement for the one in my Tx22 - swap each wire one at a time to the same pin on the new module. So I paniced when I switched it on and nothing happened, not even a light on the switch! So then I looked at the instruction paper and noticed that the 4 solder points on the LHS of the pcb appeared to be different to the one on my original. By some miracle I managed to find my original kit instructions from 10 years ago and eventually worked out that the Led wire and 3.1v supply wire have been moved around between the 4 pins ( there were only 3 on my old one). Rearranging them got the Tx working correctly!

I have had this problem several times. I have found it is usually caused by allowing the 9v battery voltage to fall below a certain voltage threshold, (don't know the value of this) but whenever I have accidently left the transmitter on for several days and run the battery down, it will often then exhibit this loss of remembering the pairing with the receiver. I now keep a regular check on the battery voltage

[steveh99]

Interference issues:
1. Servos tend to be things like trapped wires, on metal bodied loco's.
2. There are some really dreadful small electric motors out there.. Electrical noise from the motor can get back into the speed control, and confuddle it.

A ferrite on the motor leads, and a couple of 0.1uF ceramics on the motor, usually cure this.

Phil.P

I have found sometimes you need to ground the inertia pin 6 to cure this problem (assuming you are not using inertia for an ESC) I have servos on chaneels 1 & 3 for live steam loco and don't need any inertia function of the Tx

[philipy]

I have had this problem several times. I have found it is usually caused by allowing the 9v battery voltage to fall below a certain voltage threshold, (don't know the value of this) but whenever I have accidently left the transmitter on for several days and run the battery down, it will often then exhibit this loss of remembering the pairing with the receiver. I now keep a regular check on the battery voltage

Thanks Steve. No it wasn't Tx battery voltage. I did change the battery to be sure.
It was definitely to do with the core Tx2 module, and since replacing it other issues seem to have disappeared as well.

[Phil.P]

Interference issues:
1. Servos tend to be things like trapped wires, on metal bodied loco's.
2. There are some really dreadful small electric motors out there.. Electrical noise from the motor can get back into the speed control, and confuddle it.

A ferrite on the motor leads, and a couple of 0.1uF ceramics on the motor, usually cure this.

Phil.P

I have found sometimes you need to ground the inertia pin 6 to cure this problem (assuming you are not using inertia for an ESC) I have servos on chaneels 1 & 3 for live steam loco and don't need any inertia function of the Tx

A 'bespoke' transmitter then?

Never a good idea to have inputs 'floating'. - Either tie them low (ground) or from the junction of a pair of 10k resistors between 3.3V and Ground (mid-position).

Phil.P