Black 5 TTS decoder issue

[2foot6]

I have an issue with a Black 5 TTS  decoder that was just fitted to a loco ( 2-6-0 Bachmann) that had a A4 TTS decoder that worked very well.The Black 5 will not move the loco but sound is ok.I reinstalled the A4 decoder and it works well,then reinstalled the Black 5 decoder ,same problem ,will not move..The Black 5 decoder works well in other locos including an Athern,just not in the 2-6-0 Bachmann.I have reset the decoder,played around with the 150-154 motor settings ,still no resolve.The summary is the Black 5 decoder works in other locos,but not the 2-6-0,the A4 decoder works in the 2-6-0 and other locos.I'm starting to think it may be  a current draw issue (BEMF) as the decoder works well in the 2-6-0 on DC and I have a second  Black 5 decoder having the same issue,both decoders arrived today in the mail and are new.Any suggestions would be helpful. 

[96RAF]

Ask HCC about them.

[ColinB]

I doubt it is a current draw issue. In my experience if it is a current draw issue you normally have a dead decoder, the Hornby ones aren't very robust. A favorite I have found is the pins on the decoder, some are thicker than others and in some of them the gripping mechanism in the pin in the socket is broken. So on your Black 5 have a look at pins 1 and 5 on the 8 pin socket. So possibly the other decoders have slightly thicker pins and the socket connects with them better. The A4 is a slightly older design, so may use thicker pins. I had this same issue with a Zimo decoder. I have a Black 5 fitted with the TTS decoder and it does work although my one is a Hornby. I mean RAF96 is probably going to pull me up, but electrically the decoders are all the same, unless the Black 5 has something special in its "back emf" detection software, but I doubt it, usually always mechanical. Also look at the 8 pin sockets on the different locos, Hornby sometimes use 8 pin dual in line socket strip other times individual sockets soldered into the circuit board. You could snip the capacitor off across the motor that might be causing issues, but as you say another decoder works ok. Does your Black 5 have an 8 pin socket or 21 pin one?

[2foot6]

Thankyou for your replies,the decoder is a Black 5 TTS  decoder that was just fitted to a loco ( 2-6-0 Bachmann) .The loco has an 8 pin socket I hard wired a few years ago.I will check the pins to make sure they are contacting,the next step would be to hard wire the decoder to elliminate all possibilties of open circuits.I don't believe the decoder is faulty as ity works well in other locos.Will do some more checking today and advise of the results.

[96RAF]

Be aware that if you cut the plug off then the warranty is void as Hornby have no way of checking the decoder for a fault.

[ColinB]

Don't hardwire the 8 pin socket, that removes an awfully good debugging tool, plus you cannot revert back to DC easily. Also it makes it difficult to change decoders. Just look at the socket if it is faulty put another one in. I have converted loads of my old Hornby tender based locos and I always use a socket for the good things it gives me. I only wish someone would make a decent PCB based socket, unfortunately the Hornby ones are awful and the cloned ones you get on EBay are too big.

I agree nothing wrong with the decoder if it works in other locos. I suppose the only other thing to check is on the 8 pin socket check there aren't any shorts across pins you don't use, pins 2,3,6 and 7 unless you have lights on the black 5, just in case on the newer TTS decoders Hornby have changed the way they drive those pins.

[2foot6]

Thankyou for the advise,I hard wired the decoder and it started to move the loco then it stopped.I still don't know why it is being a pain but I resoldered the plug to the decoder and fitted the decoder to another loco where it works very well with no issues.I then hard wired the other Black 5 decoder to the loco and it works very well .Not all decoders and motors are exactly the same in a production line and I think I must have a motor not quite right and the decoder may not be quite rtght and they just didn't want to co-operate.It is odd when I fitted the other Black 5 decoder to the loco everything was OK and the first decoder works well in another loco.Once again thanks for your replies but this one remains a mystery.RAF 96...I have returned decoders to Hornbty after hardwiring and they were replaced,I just resolder the wires back on to the decoder plug and I do advise the Hornby team I would be doing this ,have had no problems and I have always had good dealings with the Hornby repair team.