Stopping jerkiness

[7013]

To start with the positive is that I am going to replace the Sapphire decoder with something better and more reliable. I have a Bachmann 3F which on DC is a nice runner, I have had it chipped with a Hornby Sapphire for a while. I am not a great one for messing about too much with CVs but I do like to set the acceleration and deceleration rates which on this loco are set at CV3=20, CV4=30. Now this loco has always been a bit jerky so reading on the site I noted that reducing the BEMF could resolve that to a certain extent, so I reduced the BEMF to a low number first which did not help much, then to 1 which did help but the acceleration and deceleration were affected and also the slow running which was poor, the plus side was when the loco did get going it is very smooth.

I have resolved to replace the Sapphire but would like to know a bit more about how I may be able to sort out this dilemma, Are there other Cvs I could have altered to get a proper start on the CVs i Set and a smooth ride, it appears with the Sapphire you get one or the other, however I do not want to chuck it away if I can solve the problem.

I have used TCS and Lenz 21pin decoders without problem, the TCS have been excellent in my CL22s.

[250BOB]

Jerkiness in my opinion has been down to two things......first of all the quality of decoder you are using, and secondly, but only occasionally, removing the capacitors from the loco has helped a little.

 

I have never had any success altering BEMF or any other cv's for that matter.

 

I always try to use Lenz decoders where at all posible.

 

Bob

[7013]

Thanks Bob, I always remove the capacitors and yes I believe this Sapphire is not up to the mark, never have problems with the R8249 though, I guess it is a matter of biting the bullet and getting a Lenz decoder. I have used one other Sapphire in a Diesel loco and it has behaved impeccably which leads me to believe that this decoder is either a rogue or does not get on with the Bachmann 3 pole motor. This decoder will be consigned to a diesel in future to see if it performs any better

[tender]

Why not try the TSC decoder you have in the CL22 in the 3F? My 3F works fine with the TCS decoder. The Lenz decoder also seems to work well with most recent Bachmann Steam locos.

[7013]

Thanks tender, I did have the Sapphire in my CL 22 and TCS in my 3F, but I swapped them round. Anyway I drove over to A&H models today to pick up a Lenz silver but they were closed so its back tomorrow.

[7013]

Bought myself a Lenz silver today, which has improved the running of the loco a great deal. there is still a slight hesitation when starting but I can live with that. I thought I would check the motor just to make sure there were no capacitors. There were none of the traditional looking browny coloured blobs that I have removed on previous locos, however there were a couple of things that looked like resistors or transistors in the wiring loop, They looked blue with small coloured rings around them, I resisted the temptation to chop them out but wondered what they might be? I have never seen them on any other motors, Can anyone shed any light? are they a different type of capacitor? intriguing why they should be on the motor, wondered if it was something to do with the 21 pin decoder socket

[flapland]

Those are resistors, a lot of Bachmann loco's have them. You can work out their value be comparing the coloured rings the following website. Afraid its 30 years since I did my O Level physics so I can't tell you how much they are reducing the voltage into the motor.

 

http://www.dannyg.com/examples/res2/resistor.htm

[7013]

Thanks flapland I will not be messing around with them, I bought a Lenz Silver 21pin, what a difference, smooth acceleration no jerkiness, cured. i will reset the Sapphire and try it in a diesel loco in future.

[Dagworth]

Those are resistors, a lot of Bachmann loco's have them. You can work out their value be comparing the coloured rings the following website. Afraid its 30 years since I did my O Level physics so I can't tell you how much they are reducing the voltage into the motor.

 

http://www.dannyg.co...s2/resistor.htm

 

They are not resistors, they are chokes (coils) and need to be either left in place or if removed then replaced with wire links.

 

Andi